[From the U.S. Government Printing Office, www.gpo.gov]
RETROFIT PLANNING FOR URBAN STORMWATER RUNOFF .. ... .... .. ........... ... . . ... .. . ... . ..... . . ... ....... ......... .............. ........... ............... ....... ......... .............. ....... .............. ........ ............... ...... ............... .............. . ... .. ..... ........... ... . ...... .. . .... .. ................ ........................ ............................... " ............. . . .............................................. ........ ................... ............. .................................... ............. . . ...................................... .... .. ...................................................... ................................................ .......... ............................................. ...................................................... ........... .................. .................................................. ............................... ............ ................................................................................. ............................................................................... .. ......... ............... ........................................... ..................................I................................................. ...................................................... ........................................................................ ........................................................ .......... ....... ............................ 11 ................................................ ............................................... ............................................ .......................................... .............................. ..................................... ........................ ... REGIONAL PLANNING COUNCIL ANNE ARUNDEL COUNTY 0 BALTIMORE CITY 0 BALTIMORE COUNTY CARROLL COUNTY 0 HARFORD COUNTY 0 HOWARD COUNTY STATE OF MARYLAND COASTAL ZONL TD INFORMATION CENTER 657 A66 1988 U.S. DEPARTMENT OF COMMERCE NOAA COASTAL SERVICES CENTER 2234 SOUTH HOBSON AVENUE CHARLESTON, SC 29405-2413 RETROFIT PLANNING FOR URBAN STORMWATER RUNOFF Prepared for Property of CSC Library Regional Planning Council 2225 North Charles Street Baltimore, Maryland 21045 Project Manager Lawrence Leasner Prepared by The Environmental Center Anne Arundel Community College Arnold, Maryland 21012 Principal Author Samuel R. Martin Consultant Editor Joelle Lofton January 1987 Technical Advisory Committee Lawrence Leasner, Chairman Janice Outen Earl Bradley Marcus Pollack Myra Brosius Cathy Rappe Mary Dolan James Rooney Linda Haghighat Gwynne Schultz Marie Ha-lka Earl Shaver Pieter de Jong Paul Soloman Steve Kay William Stack Charles McCulloh Andrea van Arsdale Margaret Martin William Wolinski Support Provided by The Maryland Department of Natural Resources Coastal Resources Division, under a grant from the National Oceanic and Atmospheric Administration. Additional Support Provided by Other Individuals who helped in the successful completion of this project: Dr. Hermann Gucinski and Cathy Beall, The Environmental Center; Dr. George Gibson, University of Maryland; Tom Schueler, Metropolitan Washington Council of Governments; Ginger Ellis, Anne Arundel County Office of Planning and Zoning; Mike Clar, Jeff Hutchins, and Ray Green, Engineering Technologies Associates, Inc.; Gene Driscoll, E.D. Driscoll Associates, Inc.; Pamela Harris, Graphics Consultant; Mike Guercio; Leonard Fink and Rick Broughton, RPC. Send Inquiries to: Coastal Zone Coordinator Regional Planning Council 2225 North Charles Street Baltimore, MD 21218 ii ABSTRkCT The State of Maryland, with rapidly urbanizing watersheds draining to the Chesapeake Bay, has made significant strides in managing urbanizing area stormwater runoff quantity and quality during the last decade. Existing urban areas are subject to the same environmental laws but have not been given the same management attention. This guide is designed for those planners, engineers, and others in local, state, or Federal governments who manage watersheds or make decisions regarding water quality in existing urban areas. The term "retrofit" refers to improving the quality of urban stormwater runoff to whatever degree is achievable considering water quality problems, technology limits, and budget constraints. The improvements can include the modification of existing or addition of new management practices. Improvements also may include changes in activities or land uses. Users will be helped to: (1) assess pollutant runoff from existing urban development, (2) select cost-effective controls, and (3) develop and implement retrofit strategies. assessing the pollution potential of stormwater runoff from existing urban land and designing control strategies to reduce the pollution. In using this method, the user completes a six method. Step 1 divides the jurisdiction into watersheds and ranks them by priority. Steps 2 through 5 focus on smaller drainage areas called "analysis areas" in a single priority watershed. These steps define the analysis area characteristics, pollution potential, initial rank by order of concern, site conditions and opportunities, and retrofit management strategies. The management practices are divided into three general control categories - source, erosion, and stormwater runoff. Step 6 assembles and implements a retrofit plan for each priority watershed in the jurisdiction. With a properly devised retrofit plan, the stormwater pollution, runoff velocity, and/or runoff volume can be reduced. After working through this guide, users of the Urban Retrofit Planning Method will be able to integrate the control of runoff pollution from urban areas into water quality management programs of the local, state, and Federal governments. Users also can apply the method (as one of the tools) to develop local Chesapeake Bay Critical Area plans and programs and investigate the quality of stormwater runoff in urban areas. Finally, users can apply the retrofit method as part of a comprehensive watershed management process. CONTEMS Page Contents iv Figures vi Tables vii Worksheets vii Preface viii Part I The Urban Retrofit Planning Method 1 Introduction 2 Six Steps to Urban Retrofit Planning 5 Step 1 - Select Priority Watersheds 6 Step 2 - Define the Characteristics of the Analysis Areas 14 Step 3 - Determine Pollution Potential and Rank Analysis Areas 19 Step 4 - Develop a Profile of Urban Conditions and Retrofit Opportunities 36 Step 5 - Develop Urban Retrofit Strategies 45 Step 6 - Assemble and Implement Urban Stormwater Retrofit Plan 60 Part II The Method Applied 64 Introduction 65 Six Steps in the Magothy River Watershed 65 Appendices (see next page) Glossary Gls-1 Resource Directory kes-1 References Ref-1 iv These Appendices are cited in the text: Appendix Faae A Segments in the Baltimore Region A-1 B Water Quality Evaluation Values B-1 C Maryland Watershed Priority List C-1 D Using Natural Soil Groups to Assess Existing Urban Areas D-1 E Maps for Detailing Site Conditions E-1 F Summaries of Urban Retrofit Management Practices F-I v FIGURES Page 1.1 Levels of Focus in The Urban Retrofit Planning 3 Method. 1.2 Six Urban Retrofit Planning Steps. 4 2.1 Watersheds in Anne Arundel County. 66 2.2 Alternative analysis area scales. 69 2.3 Analysis area boundaries in the Magothy River Watershed. 70 2.4 Land use map of the Magothy River Watershed. 71 2.5 Erodible soils in the Magothy River Watershed. 75 2.6 . Land use map overlaid on erodible soils. 76 2.7 Slope map of the Magothy River Watershed. 78 2.8 Land use map overlaid on slope map. 79 2.9 Land use and topography in Deep Creek. 86 2.10 Hydrologic soil groups in Deep Creek. 87 2.11 Soil erodibility in Deep Creek. 88 2.12 Slope ranges in Deep Creek. 89 2.13 Possible locations for retrofit control measures. 96 vi TABLES Paae 1.1 Source Control Management Practices. 51 1.2 Erosion Control Management Practices. 53 1.3 Characteristics of Urban Retrofit Management Practices. 54 1.4 Urban Stormwater Runoff Management Practice Costs. 59 2.1 Comparison of Anne Arundel County Watersheds. 67 2.2 Magothy River Analysis Area Information. 72 2.3 Deep Creek Analysis Area Composite Runoff Coefficient.74 2.4 Magothy River Analysis Area Erodibility and Slope 77 Factors. 2.5 Magothy River Analysis Area Pollution Factors Matrix. 81 2.6 Magothy River Analysis Area Pollution Potential Matrix - Equal Weights. 82 2.7 Magothy River Analysis Area Pollution Potential Matrix - Unequal Weights. 83 2.8 Survey results of Deep Creek subwatershed. 90 2.9 Deep Creek Urban Retrofit Strategy. 99 WORKSHERTS 1.1 Watershed Comparison and Ranks. 9 1.2 Analysis Area Information. 17 1.3 Composite Runoff Coefficient. 21 1.4 Erodibility and Slope Factors. 24 1.5 Analysis Area Pollution Potential Factors. 27 1.6 Analysis Area Pollution Potential. 31 vii PREFACS Water quality management has reached new horizons during the last two decades. Add to the long-term study of and success in controlling point sources of pollution the more recent concern for nonpoint pollution and its management. The result: the reason for this guide. The Baltimore region is a major source of urban stormwater runoff. The potential for urban lands to generate a wide range of physical, chemical, and bacteriological pollutants was demonstrated in the 1983 U.S. Environmental Protection Agency's Nationwide Urban Runoff Program. Typical pollutants found in Baltimore's urban runoff include: sediment, nutrients (both nitrogen and phosphorus), oxygen demanding substances, heavy metals, and other toxic chemicals. The urban lands drain into watershed streams and lakes and the Chesapeake Bay. Studies of these receiving waters indicate that urban runoff and other pollutant sources have caused such problems as sedimentation, algal blooms, eutrophication, contamination and death of fishery resources, and damage to the aquatic habitat. In 1984, the Maryland General Assembly recognized the role of urbanization in the degradation of the Chesapeake Bay, and @pproved a set of "Chesapeake Bay Initiatives." Included in the initiatives are two programs that address the control of pollutants from urban areas: Critical Area Protection and Stormwater Pollution Control Cost-Share Programs. This document contains guidance for assessing the pollution potential of stormwater runoff from existing urban land and designing control strategies to reduce the pollution. This guide is designed for those in local, state, or Federal governments who manage watersheds or make decisions regarding water quality in urban areas. Users--ideally an experienced team of planners, engineers, landscape architects, biologists, ecologists, and informed citizens--will be helped to assess pollutant runoff from existing urban development, select cost-effective controls, and develop and implement retrofit strategies. After working through this guide, users of the Urban Retrofit Planning Method will be able to integrate the control of runoff pollution from urban areas into water quality management programs of the local, state, and Federal governments. Users also can apply the method (as one of the tools) to develop local viii Chesapeake Bay Critical Area plans and programs and investigate the quality of stormwater runoff in urban areas. Finally, users can apply the retrofit method as part of a comprehensive watershed management process. Users must note: First, this guide will not provide all of the information required to develop retrofit management strate- gies for all situations. Users should consult the References and Resource Directory sections as well as other information sources. Second, The Urban Retrofit Planning Method only addresses stormwater runoff from existing urban land in an appropriate drainage area. The method neither replaces required site specific investigations and engineering design nor provides a uniform solution for all instances. ix Part I The Urban Retrofit Planning Method IMMODUCTION The purpose of the Urban Stormwater Retrofit Planning Method is to identify and rank drainage areas with existing urban lands in order of concern; assess methods for reducing pollution from the stormwater runoff of existing areas; and develop appropriate retrofit strategies for implementation. In this guide, "retrofit" refers to improving the quality of urban stormwater runoff to whatever degree is achievable considering water quality problems, technology limits, and budget constraints. The improvements can include the modification of existing or addition of new management practices. Improvements also may include changes in activities or land uses. In using this method, the user focuses on three levels, decreasing in size and increasing in level of detail: (1) the watershed; (2) analysis (drainage) areas; and (3) urban areas. (See Figure 1.1) The user completes a six-step process (Figure 1.2). Step 1 divides the jurisdiction into watersheds and ranks them by priority. Steps 2 - 5 focuses on smaller drainage areas called "analysis areas" in a single priority watershed. These steps define the analysis area characteristics, pollution potential, initial rank by order of concern, site conditions and opportunities, and retrofit management strategies. Step 6 assembles and implements a retrofit plan for each priority watershed in the jurisdiction. With a properly devised retrofit plan, the stormwater pollution, runoff velocity, and/or runoff volume can be reduced. 2 Figure 1.1. Levels of Focus in the Urban Retrofit Planning Method. LOCAL JURISDICTION ............. ........... ........ . .... . . . . . . . . . . . . . . . . . . . PRIORITY WATERSHED \% ANALYSIS AREA . .. ............ .......... 00 4 URBAN AREA Note: Only analysis areas with urban lands are included in the method. 3. Figure 1.2. Six Urban Retrofit Planning Steps. Planning Level Jurisdiction Step 1 Select t Priority Watersheds Watershed Watershed Step 2 Define Characteristics of the t Analysis Areas Analysis Area (Urba@Areas) Step 3 Determine Pollution Potential of Analysis Areas Step 4 Develop a Profile of Urban Conditions and Retrofit Opportunities Step 5 Develop Urban Retrofit Strategies Analysis Area Step 6 Assemble t and Watershed Implement Urban Retrofit Plan Juristiction 4 I I SIX STEPS TO URBAN RETROFITTING I I I I I I I I I I I I I I I I 5 i Step 1 -- A Synopsis Select Priority Watersheds A. Map the Jurisdiction and Divide into Watersheds. OR B. Tabulate Evaluation B. Allow Concensus Factors, Values, Judgment of Scores for Each Technical Staff. Watershed. C. Rank Watersheds C. Select Priority Select Priority Watersheds. Watersheds. Note: The user may bypass Step I if the local government has already selected one or more priority watersheds for developing urban retrofit plans, ... the municipality is a local government located within one watershed. See discussion on concensus judgment in Step 3. 6 Select Priority Watersheds A. Map the local jurisdiction and divide into watersheds. Define the boundaries of all watersheds on a map that includes the entire jurisdiction. A map scale of 1 inch = 1 mile or larger is adequate for counties, while smaller municipalities could require 1 inch - 1000 feet or larger scale maps. Designate all sub-basins and segments according to the Maryland classification system and define them as watersheds. The Maryland Classification System. The State of Maryland uses a classification system to define the boundaries of major drainage areas. The first (major) is classified as a basin; the next level is the subbasin; and the last level is the segment. All drainage areas in the Baltimore region are located in the North Atlantic Slope Basin. The seven subbasins located in the Baltimore region are listed in the following chart. Basin: North Atlantic Slope Number: 02 Subbasin Subbasin Name Classification No. 12-02 Lower Susquehanna River 13-07 Bush River 13-08 Gunpowder River 13-09 Patapsco River 13-10 West Chesapeake Rivers 13-11 Patuxent River 14-03 Middle Potomac River Each of the subbasins comprises smaller drainage areas (segments). The segments for the Baltimore region are listed in Appendix A. (See State Office of Environmental Programs' Maryland Water Quality Inventory (1986) for maps and an additional discussion.) 7 B. Tabulate evaluation factors, values, and scores for each watershed. To select a priority watershed, the user must develop values and scores for certain physical, water quality, and socioeconomic factors. Enter the results in Worksheet 1.1 Watershed Comparison and Ranking Worksheet (see page 9). Watershed Name - Enter the Maryland subbasin, segment, or other name for each watershed in column (1). Watershed Area - Use a planimeter or alternate method to calculate the total watershed land area in acres. Measure the drainage boundaries on a I inch = 1 mile or larger scale map. Enter the results in column (2). Urban Area - Outline the total urban area on a 1 inch = 1 mile or larger scale map. Calculate the area in acres. Enter the results in column (3). The urban area is defined as the combination of all residential (greater or equal to 1 dwelling unit per acre), commercial, industrial, developed institutional, and transportation-related lands. Percentao Urban Land - Calculate the percentage of urban land in each watershed. Percentage Urban Urban Area x 100 [Eqn. 11 Land Watershed Area Column (3) Column 4 x 100 Column (2) Enter the results for each watershed in column (4). Curzent Watershed Population - Estimate the current population for each watershed. Overlay watershed boundary maps on local geographic areas where current populations have been determined and prorate the populations. Geographic areas where populations may have been calculated include sanitary sewersheds, transportation planning zones, or census tracts. Enter the results in column (5). 8 'MM MM Mm IMM us Mon M -Wor.ksheet 1. IWatershed Canparison and Ranks. JUrIsdiction Name: Date: I. D. Wtrshd. Name Wtrshd- Urban Urban Wtrshd. Population Wtr. Qual. wtrshd. Urban Density Total Area Area Land Population Density Evaluation Priority Land Score Score (Acres) (Acres) M Score Score Score (2) (3) (4) (5) (6) (7) (8) (9) (10) Totals Watershed Population Densit - Calculate the current population density of the total watershed land area. Population Watershed Population Density Watershed Area x 100 [Eqn. 21 Column 6 Column 5 x 100 Column 2 Enter the results for each watershed in column (6), page 9. Water Quali Evaluation Score - From Appendix B, find the receiving water quality evaluation value for the appropriate subbasin or segment. Obtain numerical scores from the following chart and enter the score in column (7) for each watershed. Water Quality Description Value Score Excellent E 1 Good G 2 Fair F 3 Poor P 4 Watershed Priorit Score - From Appendix C, determine whether or not each watershed.is on the 1986 Maryland Watershed Priority List. If the watershed is on the List, enter 1 in column (8). If the watershed is not on the List, enter 0 in column (8). Urban Land Score - For each watershed, use the percentage of urban land in column (4) to obtain the appropriate score from the following chart, and enter scores in column (9). Urban Land Percentage Score 0 9 10 19 20 29 2 30 39 3 40 49 4 50 59 5 60 - 69 6 70 - 79 7 80 - 89 8 90 - 99 9 100 10 Densit Score - For each watershed, use the population density (gross people per acre) in column (6), page 9, to obtain the appropriate score from the following chart, and enter scores in column (10). Population Density Score <= 1.0 0 >1.0 - 2.0 1 >2.0 - 3.0 2 >3.0 - 4.0 3 >4.0 - 5.0 4 >5.0 - 6.0 5 >6.0 - 7.0 6 >7.0 - 8.0 7 >8.0 - 9.0 8 >9.0 - 10.0 9 >10.0 10 Total Score - Add the scores for each watershed. Enter the results in column (11), page 9. Total Water Watershed Urban Density Score M Quality + Priority + Land + Score Evaluation Score Score Score (Eqn.31 Column = col.(7) + col.(8) + col.(9) + col.(10) Other factors may be important in the user's selection of a priority watershed. Three categories of possible evaluation factors follow. The user can quantify the factors with values for each watershed, expand the worksheet with any necessary column, and insert the approximate values. Urban Area Characteristics. � Urban land use classes such as residential densities, commercial, industrial (Standard Industrial Class Codes), and institutional, as well as transportation-related characteristics. o Estimated population density of the urban area. � Calculations of estimated pollutant loadings in ?tormwater runoff from the urban area. If adequate information is available, the urban runoff loads can be compared to estimated loads from activities such as agriculture, construction, and sanitary sewage pumping station overflows. (Techniques for estimating urban runoff pollutant loads are described in USEPA (May 1979), Martin (1985), and MWCOG (July 1987). Contact the Maryland Department of Environment for information on estimating other pollutant loads.) � Portion of the urban area located within a specific distance of receiving water bodies. The more distant the source of stormwater runoff from streams, lakes, or estuaries, there will be less influence on the water quality. For example, the portion of the total urban area located within one-quarter of a mile from a stream or an estuary. Receiving Water Characteristics. � Types and beneficial use classifications of water bodies receiving runoff from a watershed's urban lands. � Historical receiving water quality data. The data could be compared to Federal and state water quality criteria for frequency of violations or exceedance of a threshold level. (See the 208 Areawide Water Quality Management Plans and Maryland Water Quality Inventories for discussions of historical data.) � Impairment or denial of one or more beneficial uses. (See USEPA, Dec. 1983 for a definition.) Other Characteristics. o The level of resident public concern about the water resources in a watershed. 12 o The level of local governmental concern (from both the technical staff and elected decisionmakers) about the water resources in a watershed. These characteristics are not quantified easily but can be expressed as relative weights assigned to each watershed. For example, the watershed with the highest score in the worksheet may not be selected as the priority watershed if the residents in a lower ranked watershed have shown a significant level of interest in the water quality, are willing to perform some retrofitting on private lands, and the local government considers the lower ranked watershed to be feasible for retrofitting. C. Rank watersheds and select a priority watershed. Rank the watersheds in order of highest to lowest values based on the Total Score for each watershed in column (11) of Worksheet 1.1 (page 9). Select a watershed for retrofitting by combining the watershed rank and any other appropriate factors. Results of Stop 1 1. A watershed selected by the user for retrofitting. 2. A ranked list of other watersheds and their characteristics. These watersheds may be selected in the future for retrofitting. 13 Step 2 -- A Synopsis Define the Characteristics of the Analysis Areas A. Evaluate the Watershed and Select Scale of Analysis Area. B. Define Boundaries and Name Analysis Areas. C. Define Physical Characteristics of Each Analysis Area. D. Disregard Analysis Areas with no Urban Lands. Note: If a comprehensive watershed study was performed on the watershed, the information and procedures of Step 2 may already be available. If the watershed was the subject of a flood or other stormwater management study involving computer modeling (SCS TR -20 or other model), information on land use, drainage area delineations, maps, and storm drain system catchments may be available. 14 Define the Characteristics of the Analysis Areas A. Evaluate the watershed and select scale of analysis areas. The scale is the level of detail used to define a drainage system. To evaluate the watershed and select a scale for the analysis areas, users must combine certain physical characteris- tics of the watershed with a set of simple evaluation criteria. The process is described in the following four actions. 1. Select a Watershed Base Map and Scale. A reasonable base map and scale should be selected to record the information gathered in this step. The map scale will vary with the size of the watershed but for most watersheds in the Baltimore region, a scale of 1 inch = 1 mile is acceptable, but a scale of 1 inch = 2000 feet is better. 2. Gather Information about the Watershed. The following information should be collected for use in this evaluation: � Land use/cover inventories � Topographic maps (for defining drainage area boundaries and showing stream systems) o Water/sanitary sewer service areas (a supplement to land use information) Map this information if it not in a form compatible with the base map. Although the map scales may be different, the user can reduce or enlarge the data photographically. A digital geographic information system, (if the information has been changed to x and y coordinates for the priority watershed), will simplify the tasks of gathering and analyzing information. 3. Overlay Information on Base Map. Overlay mapped information on the base map of the watershed. Make sure levels of drainage areas within the watershed also are defined. These areas will be referred to as analysis areas. (See Test Case, Figure 2.2, page 4. Select Analysis Area Scale. Before selecting the analysis area scale, the user should consider the watershed size, urban area distribution, and available labor. � Compare the prospective analysis area size to the watershed size. A reasonable analysis area size for a medium-level urban retrofit assessment ranges from a few hundred acres to 10 or 20 square miles. � Look at the distribution of urban areas within the analysis area. Is the urban land generally distributed in clusters or is it spread over larger areas? Clustering may require a smaller analysis 15 area. o Compare the available resources for the urban retrofit assessment project with the estimated amount of work required to define characteristics in the prospective analysis area. o A procedure to help define the scale of analysis area is to perform the requirements of Step 1 for one or more example analysis areas. The results can be examined for the time and resources required. B. Define boundaries and name the analysis areas. Having selected the analysis area scale, use the topographic maps to define the boundaries. For clarity during later steps in the investigation, name and number each analysis area. (See Test Case in Part II of the guide for an example.) C. Define physical characteristics of each analysis area. Overlay the analysis area boundary map on the priority watershed information to define the following physical parameters and enter each parameter in Worksheet 1.2 - Analysis Area Information (page 17). Total Watershed Area - The land area does not include the tidal embayment area. An initial estimate of total area is listed in Worksheet 1.1, column (2), page 9. This may be adequate if the scale of map used in Step 1 is as large as the topographic map in Step 2. If not, revise based on the new information. Enter the revised value in the Analysis Area Information Worksheet (page 17). Subwatershed Name - Enter the name of the Level II drainage area in column (1), page 17. (It may be the analysis area. See Figure 2.2 in the Test Case, page Analysi Area Number and Name - Enter the appropriate information in columns (2) and (3), page 17. Land Area of Analysis Area - Use a planimeter or alternate method to obtain the land area of the analysis area. Record the value for each analysis area in column (4), page 17. Urban Land Area in Analysis Area - Measure the urban areas in each analysis area on the map. Record the values in column (5), page 17. The total should be compared to the initial estimate recorded in Worksheet 1.1, column (3), page 9. 16 Worksheet 1.2 Analysis Area Information. Priority Watershed: Page _ of Date Total Watershed Area: Acres I.D. Urban Land Areas by Use Type and Class of Sub- Analysis Area Land Urban Receiving Water Body wtrshd. Area of Area Name NO. Name Analysis (Acres) RESP COW INDP INSd Mr Area (lot size in acres) Pri. Pri. Sec. Sec. (Acres) 2 1 1/2 1/3 1/4 <=1/8 Type Class Type Class (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) Total a FM = Residential d INS = Institutioral b CM = Cbmercial e.OTH = Other urban lands c IM = Industrial Note: If an analysis area has no urban area, exclude the analysis area from further investigation. Use of Urban Land Areas - Measure the residential, commercial, industrial, institutional, and other urban areas. Other urban-related areas are those lands not included in the previous specific land uses but are part of the total area. Examples are divided, limited access highways, railways, and bare ground. The smallest unit of land measured will depend on the base map scale. At a scale of 1 inch = 2,000 feet, a minimum parcel size defined on the map is about one acre. Separate the residential values according to gross lot size. Enter all urban land areas in the appropriate columns. Type and Class of Recelvin Water - The three types of receiving water bodies are (1) stream or river; (2) lake (impounded water of 5 or more acres); and (3) estuary (tidal waters). Identify the primary and secondary receiving water bodies that are downstream of the urban areas in each analysis area. Primary receiving water bodies are immediately downstream from the urban area. Secondary receiving water bodies receive discharges from the primary water body. Enter the types in columns (16) and (18), page 17. Next assign the appropriate Maryland Water Use Class to each of the primary and secondary receiving water bodies. Current water use classes are identified for all waters of Maryland in the Maryland Water Quality Inventory (1986). Enter the primary and secondary receiving water body classes I, II, III, or IV in columns (17) and (19), page 17. D. Disregard analysis areas with no urban lands. After completing Step 1, A., B., and C., review the maps and worksheet 1.2 (page 17). Delete any analysis areas that have no urban lands. Results of Step 2 1. Maps or a digitized database of applicable analysis areas within the watershed. 2. Tabulated physical characteristics of the applicable analysis areas. 18 Step 3 -- A Synopsis Determine Pollution'Potential and Rank Analysis Areas A. Determine the Pollution Factors. OR B. Determine the Pollution Use Delphi Method Potential. to Rank Analysis Areas. I C. Rank Analysis Areas. 19 Determine Pollution Potential and Rank Analysis Areas A. Determine the pollution factors. Six ratios of analysis area physical information, appropriate weights, and the resulting evaluation factors are developed in three Worksheets 1.3, 1.4, and 1.5. Each worksheet and calculation procedures are described in the following actions. 1. Calculate the Composite Runoff Coefficient for Each Analysis Area (Rv). This method is limited to estimation of surface runoff only. For each analysis area (see Worksheet 1.2, page 17), complete a copy of Worksheet 1.3 Composite Runoff Coefficient (page 21). Area of Land Use - Consult the Analysis Area Information Worksheet !-.2-,page 17. Obtain the data from columns (6) (15) on urban land use. Enter data in column (2) of Composite Runoff Coefficient Worksheet 1.3, page 21. Percon. Imperviousness Value - Assign a value to each urban land use type represented in each analysis area. Examples of urban land use and percentage impervious values are presented in the following chart. Urban Land Use Percentage Impervious Value Residential (avg. lot size) 2 acres 12 1 acre 20 1/2 acre 25 1/3 acre 30 1/4 acre 38 1/8 acre or less 65 Commercial 85 Industrial 72 Institutional 85 (Extracted from USDA-SCS, June 1986) (Not*: The user may choose impervious factors for the watershed that are more representative of local areas.) Com.ylet Column (4) - For each category of land use, multiply i-hearea of land use by the percentage impervious value. 20 Worksheet 1.3 Composite Runoff Coefficient. Priority Watershed Date Analysis Area No. Name Use of Land Area of Percentage Land Use Impervious Col.(2) x Col.(3) Area Value (Acre) (Acre) (1) (2) (3) (4) Residntl. 2 ac. Resid. 1 ac. Resid. 1/2 ac. Resid. 1/3 ac. Resid. 1/4 ac. Resid. <=1/8ac. Commercial Industrial Institutional Other Urban Land All Other Land Total Weighted Percentage Total col.(4) Impervious Urban Land in Analysis Area Total col.(2) Composite Runoff = 0.05 + 0.009( Wtd- Pct- Imp. Area) Coefficient (Rv)a = 0.05 + 0.009( Transfer Rv for each Analysis Area to col.(12) in Analysis Area Pollution Factor Worksheet. a source of equation: MWCOG, July 1987. 21 Calculat the Wei-qbted Percentaor gf impervious Urban Land in each Anil-ysl Area - (Equations in Composite Runoff Z-oe'fficient Worksheet' 1.3, page 21.) Calculat the Composite Runoff Coefficient (Rv) for the Anal-ysis - (Equation in the Composite Runoff Coefficient Worksheet 1.3, page 21.) 2. Determine the Erodibility of Soils and Slope of Land Ratios. Determine the Erodibili of Soils Ratio - The combined percentage of moderate, high, and very high erodible soils underlying the urban area in each analysis area is determined in five actions: � Obtain current soil survey map sheets of the watershed area from the local Soil Conservation District Office. � Consult Appendix D. (Information in Appendix D has been exerpted for the Baltimore region counties from Natural Soil Groups of Maryland (1973)). Trace the boundaries of the soil mapping units on an overlay of the soil survey sheets. Match each mapping unit to the appropriate natural soil group in Appendix D and label with the soil group symbol. The result is a natural soil group overlay map of the watershed. � Assign each unit on the natural soil group overlay map with a Moderate, High, or Very High erodibility class, if appropriate, to form an erodibility class map . The natural soil groups, erodibility K-factors, and classes are shown in the following chart. Class K-Factor Natural Soil Groups Very Low 0.17 Ala, Alb, Alc, A2. Low 0.22 - 0.28 Cla, Clb, Clc, Dla, Dla, D1b, D1c, El, F2. Moderate 0.32 Bla, Blb, B1c. High 0.37 B3, C2, E3. Very High 0.43 B2a, B2b, B2c, E2a, E2b, F3. N/A F1, G1, G2, G3. Hla, Hlb, H1c, H2a, H2b, H2c. 22 N/A - Refer to the Natural Soil Groups -of Maryland for further explanation and assignment of a K-Factor. ** These groups are too variable to rate. Determine the specific soil series name from the detailed soil survey series map and use the information for the group containing that series. o Measure those areas discussed above in each analysis area. (Overlay the natural soil group erodibility class map over the urban area map of the same scale.) Enter the total urban area over erodible soils value, for each analysis area, in column (6), Worksheet 1.4 - Erodibility and slope Factors (page 24). The Worksheet also uses the information in columns (1) - (5) from Worksheet 1.2 - Analysis Area Information, page 17. o Determine the Erodibility ratio. For each analysis area, compute: Total Urban Area over Erodible Soils Erodibility of in an Analysis Area Soils Under x 100 Urban Area Ratio Urban Area in an (Eqn.41 Analysis Area Calculate the Erodibility of soils ratio for each analysis area as follows: Column (6) Erodibility & Slope Factors Worksheet 1.4 (page 24) Erodibility of x 100 Soils Ratio (R) Column (5) Analysis Area Information Worksheet 1.2 (page 17) 23 mmm mmmm m @ m Worksheet 1.4 Erodibility and Slope Factors. Page - of Priority Watershed: Date I.D. Sub- Analysis Area Land Urban Urban Area Urban Urban Area Urban wtrshd. Area of Area over Erodibility over Slope of Name No. Name Analysis (Acres) Erodible Ratio Moderate & Land Ratio Area Soils Steep Soils (Acres) (Acres) W (Acres) N (1) (2) (3) (4) (5) (6) (7) (8) (9) 71otal Determine the Slop of Land Ratio The slope range of land in an urban area can be determined using the natural soil groups or topographic or slope range maps. Natural Soil Groups. � Use the local soil survey map sheets obtained from the Soil Conservation District for defining the erodibility ratio, to also determine land slope classes. Individual soil mapping units are combined into groups on the natural soil group overlay map. Assign each unit on the overlay map with a moderate or steep slope, if appropriate, to form a slope class map. Slope ranges can be identified using the following chart: Class Slope Range Natural Soil Groups (percentage) Low 0 - 8 or 10 Ala, Bla, B2a, Cla, Dla, E2a, Hla, H2a. Moderate 8 - 15 Alb, Blb, B2b, Clb, 10 - 15 Dlb, E2b, Hlb, H2b. High > 15 Alc, Blc, B2c, Clc, Dlc, Hlc, H2c. A2, B3, C2, El, E3, Fl, F2, F3, Gl, G2, G3. To identify the slope range for these natural soil groups, refer to the soil survey report and soil series in these groups. o Measure the urban areas in each analysis area overlying soils in the moderate and high slope classes. (overlay the natural soil group slope class map over the urban area map of the same scale.) Measure the portion of the urban areas in the moderate and high combined slope classes. Tabulate in the Erodibility and Slope Factors Worksheet 1.4, column (8), page 24. � Compute the slope of the land ratio. Total Urban Area over Moderate & High Urban Soils in an Analysis Area Slope of Land x 100 Ratio Urban Area in an [Eqn. 51 Analysis Area 25 The slope of land ratio for each analysis area is calculated as follows: Column (8) Erodibility & Slope Factors Urban Worksheet 1.4 (page 24) Slope of Land x 100 Ratio (R) Column (5) Analysis Area Information Worksheet 1.2 (page 17) Topographic or Slope Range Maps. � obtain current topographic or slope maps (see Glossary for definition) covering the watershed. The map scale should be 1 inch = 2,000 feet or larger, depending on the level of detail used in the overall evaluation. o Identify the areas on the maps in the three slope classes used for natural soil groups or similar groupings. � Measure the urban areas in each analysis area overlying or upslope of the Moderate and High slope classes. (Overlay the slope class map over the urban areas of the same scale.) � Tabulate and compute data as in previous actions 2. and 3. under Natural Soil Groups. 3. Complete Worksheet 1.5 Analysis Area Pollution Factors (page 27). Obtain information from Worksheets 1.2 (page 17), 1.3 (page 21), and 1.4 (page 24). Analysi Area Number and Name - Enter the analysis area number and name in columns (1) and (2) of Worksheet 1.5 (page 27). Ca2cu2ate the Urban Area to Watershed Urban Area Ratio MAWAV - The ratio (R) is defined for each analysis area as follows: The Urban Area in an Analysis Area UAWUAR Total Urban Area x 100 [Eqn.61 in all Analysis Areas 26 mmmm mmm mm Worksheet 1.5 Analysis Area Pollution Factors. Page _ of Priority Watershed Date Erodibility Slope Analysis Area TJAWLIAR UAAAR AAWAR Rv of Soils of Land No. Name R W F R W F R V F R W F R W F R W F M M - M M M M (1) (2) (3) M' (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) '(20) R = Ratio F Evaluation Factor W = Weight F R x W (See Text for Calculation of Factors and Weights) AAWAR - Analysis Area to Watershed Area Ratio Rv - Cmposite Runoff Coefficient uAWUAR - Urban Area to Watershed Thtal Urban Area Ratio LWIAR - Urban Area to Analysis Area Ratio This ratio is calculated for each analysis area using results from column (5) in Worksheet 1.2 - Analysis Area Information (page 17): Column (5) UAWUAR x 100 (R) Total (column (5)) Enter each UAWUAR in column (3) of the Analysis Area Pollution Factors Worksheet 1.5, page 27. Skip columns (4) and (5). Calculat the Urban Area to Analirsis Area Ratio WAAAR) - The ratio is defined for each analysis area as follows: The Urban Area UAAAR in an Analysis Area x 100 [Eqn.71 Land Area of an Analysis Area This ratio is calculated for each analysis area using results from columns (4) and (5) in the Analysis Area Information Worksheet 1.2 (page 17). column (5) UAAAR x 100 (R) column (4) Enter each UAAAR in column (6) of the Analysis Area Pollution Factors Worksheet 1.5, page 27. Skip columns (7) and (8). Calculate the Analysis Area to Watershed Area Ratio (AAWAR) This ratio is defined for each analysis area as follows: Land Area of an Analysis Area AAWAR x 100 [Eqn.81 Total Land Area of Analysis Areas 28 This ratio is calculated for each analysis area using results from column (4) in the Analysis Area Information Worksheet 1.2, page 17. Column (4) AAWAR x 100 (R) Total Column (4) Enter each AAWAR in column (9) of the Analysis Area Pollution Factors Worksheet 1.5 (page 27). Skip columns (10) and (11). Record the Composite Runoff Coefficient for Eacb Analysi Area (Rv) - Transfer the composite runoff coefficient (Rv) from Worksheet 1.3 (page 21) for each analysis area to column (12) of Worksheet 1.5, page 27. Skip columns (13) and (14). Record the Hrodibilit-- of Soils Rati - Transfer the erodibility of soils railo for each analysis area from column (7) in Worksheet 1.4 (page 24) to'column (15), Analysis Area Pollution Factor Worksheet 1.5, page 27. Record the Slop of Land Ratio - Natural Soil Groups. o Transfer the slope of land ratio for each analysis area from column (9) in Worksheet 1.4 (page 24) to column (18), Analysis Area Pollution Factors Worksheet 1.5, page 27. Or, alternately Topographic or Slope Range Maps. o Transfer the slope of land ratio for each analysis area from column (9) in Worksheet 1.4 (page 24) to column (18), Analysis Area Pollution Factors Worksheet 1.5, page 27. Assign.# Weight for Each Evaluation Factor - In the Analysis Area Pollution Factors Worksheet 1.5 (page 27), enter a numerical value that indicates how important each evaluation factor is. A weight (W) value is assigned to a factor giving it more, equal, or less importance than other factors. If a factor is not considered important to the evaluation, give it a weight value of 0. A factor with a weight value of 1.0 allows an evaluation of the original evaluation factor. A weight value of 2.0 gives the evaluation factor twice the importance of the original 29 factor. The user should base weighting values on the physical characteristics and technical knowledge of the priority watershed. For example, if the composite runoff coefficient is considered to be a more important contributor to runoff pollution than otherfactors, it should be assigned a weight value in column (13), greater than 1.0. Enter the appropriate weights in columns (4), (7), (10), (13), (16), and (19). Calculate Weiahte Evaluation Factors - For each evaluation factor in the Analysis Area Pollution Factors Worksheet 1.5 (page 27), multiply each ratio (R) by the appropriate weight (W) to obtain a pollution Factor M for each analysis area, (R x W = F). Enter the appropriate factors in columns (5), (8), (11), (14), (17), and (20). B. Determine the pollution potential. Complete Worksheet 1.6, page 31, Analysis Area Pollution Potential. Analysi Area Number and Name - Enter identification in columns (1) and (2). Evaluation Factor Ranks - For each factor, rank the values and record the results in columns (3) - (8); assign an integer from 1 to the total number of analysis areas in the priority watershed with I representing the highest value. Break ties by assigning each tied value the rank equal to the average of the current rank position and the next greater one. For example, analysis area factors for Creek A and Creek B are 55 and 55, respectively. Normally they would be ranked 5th and 6th. However, since both analysis areas have equal values, each area is assigned values of 5.5, the average of ranks 5 and 6. Rank Score Add the evaluation factor rank values in columns (3) (8) for each analysis area and record the sum (Factor Score) in column (9), Worksheet 1.6, page 31. Determine Receivin Waters Score - Calculate the downstream receiving water score in three actions. For each analysis area obtain the primary water body type and use classes from the Analysis Area Information Worksheet. 1. Assign scores from the following chart to the primary and secondary water body types. Enter the scores in the appropriate columns (10) and (12) in the Analysis Area Pollution Potential Worksheet 1.6 (page 31). 30 mmmmm m = mm = = = mm Worksheet 1.6 Analysis Area Pollution Potential. Page - of Priority Watershed: Date I.D. Evaluation Factor Ranking Evaluation Dwnstm. Receiving Waters UPS AA Analysis Area Factor GRAND F F F F F F Score Prtaary Secondary RW SCORE No. Name 1 2 3 4 5 6 T C T C Score (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) F1 = UAWUAR Factor F4 = Rv Factor UPS = Unusual Pollutant Source F2 = UAAAR Factor F5 = Erodibility of Soils Factor F3 = AMAR, Factor F6 = Slope of Land Factor T = I@W C = Class Water Body Type Score Stream 2 Lake 1 Estuary 1 2. Assign scores from the following chart to the primary and secondary water use classes. Enter the scores in the appropriate columns (11) and (13), Worksheet 1.6, page 31. Water Use Class Score 3 1 1 IV 2 3. Calculate the Receiving Water (RW) Score by adding columns (10); (11); (12); and (13). Enter the RW Score in column (14), Worksheet 1.6, page 31. Determine if One or More Unusual Pollutant Sources (UPS) Exists - For each analysis area: Review the sources of land use information used to develop the urban area inventory in Step 2. Determine, if the following land uses or activities exist. If one or more exists, place a "+" in column (15), Worksheet 1.6, page 31. If no source exists, place a "0" in the column. 0 Heavy Industry - Those manufacturing facilities that use raw materials such as iron ore, timber, or coal. Included are steel mills, pulp and lumber mills, electric-powered generating plants, oil refineries and tank farms, chemical plants, brick or concrete blockmaking plants, and transportation transfer facilities. Often an identifying feature, stockpiles of raw maierials and waste-product disposal areas are visible. 32 0 Junkyards, wrecked automobile storage facilities, and other land uses where raw materials , chemicals, or goods are stored or exposed to the weather. 0 Older (more than 30 years), dense urban development consisting of residential or commercial land uses or both with a high degree of impervious area. 0 Developed areas with accumulated garbage or debris on streets, in yards, and in alleys - a lack of good community housekeeping. 0 Urban areas with no stormwater runoff-related pollutant discharges. Examples include older (more than 30 years old) sanitary sewered areas with potential leaking sewers; industries and automobile service stations with floor drains draining to storm sewers; and areas where chemicals and wastes are dumped. A user, unable to visit the sites, may obtain the independent assessment of unusual pollutant sources in the urban areas from one or more people who know the area. Calculate the Analys! Area Grand Score - For each analysis area calculate the AA Grand Score as follows: Analysis Factor RW Area Grand Score x Score [Eqn. 91 Score The Grand Score is calculated for each analysis area as follows: Column (16) Column (9) x Column (14) The result is entered in Worksheet 1.6 (page 31). C. Rank the analysis areas. Use the AA Grand Score and the Unusual Pollutant Source indicator combined for each analysis area to rank all analysis areas in the watershed. Consider the analysis area with the lowest grand score as the area having the greatest potential for polluting stormwater runoff. 33 The user must decide which analysis areas in the watershed to investigate further before beginning Step 4. Ideally, Steps 4 and 5 should be applied to all analysis areas defined in Step 2. Personnel and budget are two factors to consider when defining which analysis areas to retrofit. The user should bear in mind that if a creekshed is selected as the analysis area, the number of analysis areas in the priority watershed normally will range from 5 to 20, more or less. If the analysis area selected is smaller than a creekshed the user will have 30 to 100 or more analysis areas to evaluate. Instead of analyzing all analysis areas in a single period, the user can set priorities using the factor ranking. For example, the five highest ranked (lowest value) analysis areas in the watershed could be selected for analysis in Steps 4 and 5 and development of retrofit strategies and a plan in Step 6. At a later date, in a second round of analysis, the next highest ranked (lowest value) group of five analysis areas could be chosen, and so on. Alternative Ranking Procedures. Two alternative evaluation and ranking procedures for completing Step 3 follow. Concensus Judgment - is obtained by using the Delphi Technique. This procedure, applied to ranking analysis areas is described as follows: 1. Assemble a panel of participants. Include those knowledgeable of local urban land uses, water quality, and others with more specialized expertise. The panel can include both professional and lay representatives. 2. Without consulting the other panelists, each participant ranks the analysis areas within the watershed. The ranking is based on the amount of urban area in each one, other information from the Analysis Area Pollution Factors Worksheet, and personal knowledge. 3. Compile the results, and calculate the median and range of the rankings and present them to the panelists. From this list, each panelist completes a second round of ranking. 4. The process of gathering the rankings and feeding back the results is continued for one or more rounds. 5. Calculate the median of the final round. Consider it the best estimate of the top rank analysis area. other analysis area ranks are developed similarly. 34 Combination of Concensus Judgment Md Numerical Scorin - A third method of choosing the analysis areas is a combination of the two methods previously described. Derive a ranking of analysis areas using the Delphi technique. Develop a second ranking of analysis areas by numerical scoring. Compare both lists to derive a combined ranking. Results of Step 3 1. A ranking of the applicable analysis areas based on their urban area's potential to pollute receiving waters. 2. The pollution potential of the applicable analysis areas. 35 Step 4 A Synopsis Develop a Profile of Urban Conditions and Retrofit opportunities A. Gather and Organize Information. B. Perform a Site Survey. C. Develop a Profile of Analysis Area Urban Conditions and Retrofit Opportunities. D. Disregard Very Low Priority Analysis Areas. 36 Develop a Profile of Urban Conditions and Retrofit opportunities A. Gather and organize information. Resources consist of, but are not necessarily limited to maps, reports, plans, construction documents, and other information. 0 A wide variety of maps exist that may have information to describe conditions of the urban area within analysis areas. See Appendix E for a summary of 16 kinds of maps, their uses, typical map scales, and common sources. For a specific urban area, the scale is important. Generally, map scales equal to or larger than 1 inch 1000 feet - depending on the desired information are adequate for analyzing urban areas. 0 Local, state, or Federal government, or private reports concerning land use, infrastructures, transportation, natural resources, water quality, water resources, parks and recreation, and plant and animal habitats may offer information that better describes the analysis area and the enclosed urban area. An especially useful report is the Local Soil Survey developed by the Soil Conservation Service. The Environmental Impact Assessment or Statement is another important source of environmental information describing the environmental impacts on both physical and biological resources. 0 Information may be available from Federal, state, or local government agencies or private organizations such as U.S. Fish and Wildlife Service; U.S. Soil Conservation Service; U.S. Geological Survey; Maryland Department of Environment; Maryland Department of Planning; Maryland Department of Natural Resources (Forest, Park, and Wildlife Service, Fisheries Division, Coastal Resources Division); Maryland Natural Heritage Program; and County Soil Conservation Districts. Important local agencies to contact include the Departments of Health, Planning and Zoning, and Public Works. 0 Like reports, plans also may have information describing an urban area. Examples include: park and recreation, subdivision storm drain systems, land use, stormwater management, and water and sewer plans. 0 Often construction drawings, plans, specifications, and other related information can point to conditions otherwise obtainable only by special investigation. For example, the soil boring analyses (required for construction of a building or a roadway) can be used 37 to determine the feasibility of infiltration as a water quality retrofit management practice. 0 A good supplement to field surveys or a substitute for detailed field surveys is a series of recent aerial photographs of the analysis area. The aerial photos should be less than five years old, if possible, and taken at low altitude. High altitude photos are useful for larger urban areas where detailed information is not required. Sources of aerial photographs include: the (USDA) Agricultural Stabilization and Conservation Service, USDA Soil Conservation Servation, U.S. Department of Commerce National Oceanic and Atmospheric Survey, Maryland Tax Assessment Office, Maryland Gypsy Moth overflights, county-sponsored flights, and private aerial survey companies. B. Perform a site survey. An urban area survey is an information gathering task. This information is used to o check the validity of existing maps, reports, plans, and other information that describes the site, o note any unusual circumstances such as land uses that generate higher than normal pollutant loads (see Step 3, unusual pollutant sources, pages 32 and 33) or severe unchecked erosion; and o point out opportunities and constraints for application of water quality retrofit control measures. An urban area site survey normally is performed by walking through and around the site, and following the drainage system downstream to the nearest receiving water body. If the urban area is large (several hundred acres or more), a windshield survey by automobile may be appropriate. Review all information obtained before going to the site. The user should have developed or selected a map of the analysis area and urban areas to be used as the base map. The map should have a scale large enough to record accurately detailed information. A reasonable scale for small to medium sized analysis areas is 1 inch = 1,000 feet or larger. Large areas of 2,000 acres or more can be described at scales of 1 inch = 2,000 feet or larger. Set up a series of taps at the same scale which can be overlaid to combine characteristics. Visit the site. Make a special effort to: o cross the width of the site from drainage boundary to drainage boundary at several 38 intervals along the length of the area, � follow the storm drainage system from the highest to lowest elevations, � follow the storm drainage system downstream to the nearest receiving water body, � check the conditions of all areas identified in Steps 2 and 3 that have moderate to very highly erodible soils (a K factor of equal to or greater than 0.032) and moderate to steep slopes (equal to or greater than 8%). � check out any areas of public ownership for retrofit opportunities. o inspect se ctions of stream for erosion and sedimentation or any indications of problems at stormwater outfalls. Use the Site Survey Checklist at the end of Step 4 to describe the urban conditions in each analysis area and record the observations on the analysis area base map. C. Develop a profile of analysis area urban conditions and retrofit opportunities. Follow up the field survey by investigating and answering any questions resulting from the survey. This data and the Site Survey Checklist is your Urban Area Profile. When developing a profile of an urban area's existing conditions and retrofit opportunities, use the information collected and the results from this step as well as the data from the Pollution Potential Worksheet 1.6 in Step 3 (page 31), results of the field survey in Step 4, and the site base map and overlays. The profile is a summary of descriptive information presented in outline and map form. D. Disregard very low priority analysis areas. When the field survey and Site Survey Checklist are completed for an analysis area, compare the conditions with the relative ranking of analysis areas in Step 3. The analysis area can be disregarded if it has o a low pollution potential ranking when compared to other analysis areas, o adequately stabilized slopes and drainage channels with no erosion or sedimentation problems, 39 o no illegal or unusual runoff pollutant sources, oonly very low density residential (> 2 acres per dwelling unit) development with minimal impervious area, ovegetated buffers along all open drainage channels and receiving waters that reduce the effects of stormwater runoff, oexisting management practices that provide control of stormwater runoff pollutants. Results of Step 4 1. A profile of the urban conditions and retrofit opportunities in each applicable analysis area. 40 Site Survey Checklist Land Use/Cover 1. Describe the land uses and land covers of the site. The information should include: a. Type(s) b. Density(ies) c. Approximate Age of Development d. Vegetation - types and densities e. Estimate the proportion of the site taken up by each land useand cover. f. Point out areas of open space (such as parks, etc.) and their relationship to other land uses. Land Ownership 2. Document which portion(s), if any, of the urban area is publically owned or under public control. Hydrology 3. Do the drainage boundaries of the site correspond with those previously mapped? If not, change the mapped boundaries on the site base map. * 4. Estimate the total imperviousness of the site. (See Step 3.) 5. Of the site's total imperviousness, what portion is "hydraulically-effective" (that part of the paved or otherwise impervious area that discharges stormwater runoff to other paved areas which carry the runoff to a storm drain system.) * a. Where do the building roof.gutters and downspouts drain? b. Are the driveways contiguous with the streets? c. Are the surface drains paved? 6. Does the hydrologic runoff potential (A,B,C,D) from the Step 3 assessment (Natural Soil Groups) correspond with the individual soil mapping units in the local Soil Survey Report? 7. Are the ground slopes and storm drainage slopes moderate to high (equal to or greater than 8 percent)? 41 Site Survey Checklist continued 8. If maps are not available that show the storm drain system, sketch the system. * a. show approximate sizes, lengths, and locations of the: i. overland flow paths (arrows for direction) ii. swales iii. ditches iv. pipes v. storm drain inlets vi. gutters Note the natural versus artificial sections. Pollutant Sources and Problems 9. From your observations of land use, are there any activities or sites that could generate greater than normal pollutant concentrations or unusual pollutants? An example is an industry with raw materials stored outside. Also commercial establish- ments such as service stations, automobile garages, junk yards, accumulated garbage, dry cleaners and other sources that could generate pollutants. If any exist, note the location, type of activity, and materials. * 10. If a pollutant source is found that is suspected to be illegal, note the type and location and contact the proper local or state authorities. Examples include: a. A pipe with a liquid discharge into a ditch, stream, or tidal waters. b. Drums or other containers leaking fluids or powders. c. Liquid seepage boiling up from the ground or from a cut in a hill slope. d. Evidence of failing septic systems. 11. Are there obvious areas of soil erosion on the site? a. Sheet erosion (look on the lawns and other upslope areas for signs). b. Rill erosion (downslope areas with small shallow ditches generally a foot or less wide). c. Gully erosion (downslope areas, especially flatter areas near streams with obvious ditches, usually several feet across and deep). d. Exposed moderate to high slopes (equal to or greater than 8 %). e. Bare or poorly vegetated drainage channels. Locate those areas and name the type of erosion and show the source of flow causing the erosion. 42 Site Survey Checklist continued Relationship to Receiving Waters 12. Follow the drainage pathway from the urban source area to the nearest receiving water body. a. Estimate the distance. b. Is drainage pathway open or a piped system? c. Describe the conditions where the urban area runoff discharges into the receiving waters. Streambank erosion? Sedimentation? (look both up and down stream for an indication of an erosion problem.) d. What is the receiving water body (a stream, headwater drainage, tidal waters, or wetland)? e. What is the orientation of the stormwater outfall and the type? Retrofit Control Opportunities and Constraints 13. Locate all community open space areas throughout and immediately downstream of the site. * a. Point out the publicly owned areas. b. Locate those areas coinciding with the storm drainage system. c. Describe these areas. (Consider such things as type and vegetation.) 14. Are management practices currently being applied at the site that either affect or could potentially affect water quality or stormwater runoff? Examples include street sweeping, stormwater management structures or dry ponds (probably built after 1970), and riprapping in channels. * a. Name, describe, and indicate the location of these practices. b. Note the maintenance levels and frequencies. 15. The following list contains examples of land conditions and existing management practices that may coincide with the situation in the urban area under investigation. Check the conditions in the urban area against this list for possible opportunities to implement retrofit management practices. a. Roof downspouts connected to the sanitary sewer, storm sewer system, or paved surface. b. Paved sidewalks, parking lots, streets, or surfaces in need of resurfacing or replacement. c. Unused or otherwise unnecessary impervious surfaces. 43 Site Survey Checklist continued d. Curb and Gutter in need of replacement on slopes of 4 percent or less. (A potential for installing vegetated swales.) e. Stormwater inlets or catch basins or both. f. Paved open drainage channels. g. Bare foot paths, roads, or parking areas. h. Road median strips with no curb and gutter. i. Grass strips adjacent to roadways. j. Erosion and sedimentation concerns. k. Communities with unusually dirty conditions. 1. Unused stable pervious surfaces. m. Unused natural depressions. n. Dry stormwater management basins. o. Stormwater outfalls. p. Utility easements and Rights-of-Way. This information is of the highest priority for collection in a field survey. 44 Step 5 -- A Synopsis Develop Urban Retrofit Strategies A. Evaluate the Urban Areas. B. Develop an Urban Retrofit Strategy. C. Repeat Steps 5, A and B for Applicable Analysis Areas. 45 Develop Urban Retrofit Strategies A. Evaluate the urban areas. If the analysis area has existing urban stormwater management practices (unlikely in pre-1970 construction) or an extensive improved storm drainage system, evaluate the individual urban area or clusters to determine if modifications are needed. For example: an urban area drains to a dry stormwater management (detention) basin designed to retain a 2-, 10-, or 100-year runoff event. The retrofit analysis may point out an opportunity to retrofit the basin into an extended detention basin designed to hold smaller runoff events for water quality benefits as well as control larger events that cause stream erosion and flooding. The evaluation procedure for existing management practices: 1. Compare the Urban Conditions Profile with: Table 1.1 Source Control Management Practices. Table 1.2 Erosion Control Management Practices. Table 1.3 Characteristics of Urban (Stormwater Runoff) Retrofit Management Practices. at the end of Step 5, pages 51 through 58. 2. Consider whether changing an existing source control management practice shown in the profile would improve control. (See the Resource Directory, page Res-1, for specific information about source controls.) 3. Assign the appropriate erosion controls listed in Table 1.2 (page 53) to the erosion problems and past correction efforts identified by the site survey in Step 4. Note that a combination of practices normally is needed to address erosion and manage stormwater runoff. The user also must evaluate the upslope contributing drainage area and use of stormwater controls (Tables 1.2 and 1.3) 4. Review the list of stormwater runoff management practices and characteristics in Table 1.3 (pages 54- 58) and the Urban Area Profile. Consider any management practice in the urban area a candidate for retrofitting. However, in construction of the 1970's, the most common stormwater management practice covering a large drainage area was the dry detention basin, designed to control the 2-, 10-, or 100-year runoff event. (See Appendix F, Summaries of Urban Retrofit Management Practices, for information about specific management practices.) 46 Also consider the stormwater runoff management practices used in residential and commercial areas to handle building roof runoff. In typical lower density residential areas, roof runoff drains to splash blocks and lawns. However, in some residential communities and commercial districts, roof drains are drain to paved areas or are connected by pipes to streets, storm drains, or even sanitary sewers. After evaluating the urban area for opportunities to modify existing management practices, a second evaluation is necessary to determine the potential for applying new practices. Evaluate each urban area: 1. Examine the source control management practices listed in Table 1.1 (pages 51-52) for possible application to the urban area. Many of these practices can be implemented in large geographic areas - throughout the priority watershed or the local jurisdiction. 2. Potentially the most cost-effective set of management practices to apply in the urban area is where evidence of erosion is seen in the field surveys (Step 4) or indicated in the pollutant potential scoring (Step 3). These controls (shown in Table 1.2) normally are applied with stormwater runoff management practices (Table 1.3), to address both the effects of erosion and the source of stormwater runoff. 3. Compare the Urban Area Profile to the Characteristics of Urban Retrofit Management Practices Table (Table 1.3, pages 54-58). 0 Using the site base map, follow the pathways of storm runoff noting the drainage features. Compare each segment of the system and the Urban Area Profile with appropriate management practices and characteristics in Table 1.3, summaries of management practices in Appendix F, and supporting information in the Resource Directory. 0 Define the approximate drainage area that will be treated by the management practice and record any practice that matches the site profile conditions. Also record the characteristics of the practice and location. Urban Retrofit Measures. Urban retrofit measures improve the quality of stormwater runoff by either: (1) reducing or removing the supply of 47 pollutants on the land prior to or between storm events or (2) delaying, infiltrating, storing, or treating the water as it runs off the land. The stormwater runoff can pick up pollutants from the land and, because of the volume, velocity or both, generate pollutants by eroding the land surface, drainage channels, or stream beds and banks. Certain management practices for stormwater runoff also can be designed to handle the volume and rate of release. Known management practices considered applicable for retrofitting in existing urban areas are grouped in the following three categories: 1. source controls - are nonstructural, that is they are human activities and living patterns rather than physical structures. Source controls are not restrained by drainage boundaries and can be applied to large areas. These controls affect the supply of pollutants on the land surface before rainfall by (1) preventing the introduction of pollutants to the land surface; (2) reducing or timing the frequency of application of potential pollutants to the land; or (3) removing the accumulated pollutants from the land. Some controls require implementation by the individual. Others are best carried out at the community or municipal level. Initial costs often are low but increase with operation and maintenance activities. See Table 1.1, pages 51-52. 2. Erosion controls - Although erosion is a result of stormwater runoff over susceptible land (erodible soils or steep slopes or both), it has a separate category of controls. Erosion problems @re, by comparison to other urban runoff issues, more easily identified by a site survey. When a specific erosion problem has been identified, the control practices include ground covers and earth retention devices. Stormwater runoff controls also are applied to manage the water source. See Table 1.2, page 53. 3. Runoff controls - generally are organized by location along the path of flow. The management practices should be used as a guide for performing a "downslope" retrofit assessment. (The user begins at the top of the drainage area boundary and investigates retrofit control options while proceeding down the slope to the stream or other receiving water body.) The characteristics of runoff controls vary with each control. See Table 1.3, pages 54-58. Unlike source controls, the initial costs of runoff controls are often substantial - usually because of the land and construction requirements. See Table 1.4, page 59, for a summary of approximate costs. The user must study the characteristics of each practice being considered for the retrofit plan to determine if the practice will be suitable for the areas. The characteristics of 48 the control practices for retrofitting an urban area are listed in Table 1.3. The table is divided into four parts : (1) Physical Site Conditions and Requirements; (2) Management Capability; (3) Environmental Impacts; and (4) Costs and Responsibility. The user also can determine all the possible management practices that may be applicable in a specific urban area. The user should use the table to 0 weigh the advantages and disadvantages of the practices being considered, 0 achieve a reasonable removal of pollutants at a minimum estimated cost, 0 choose practices that can be implemented with minimal impacts to the environment and community, and 0 select combinations of practices with minimum operations and maintenance burdens. An important purpose for retrofitting an existing urban area is to reduce the pollutants in stormwater runoff. Studies by the State of Maryland (see summaries in Water Quality Inventories 1975-86), U.S. Environmental Protection Agency (Dec. 1983), Martin (1985 and 1986), MWCOG (1986 and July 1987) have found that urban runoff is a significant contributor to the impairment or denial of beneficial uses in receiving waters. Typical pollutants found in runoff that help cause water quality problems include: sediment, both nitrogen and phosphorus nutrients, oxygen demanding organic substances, heavy metals ( lead, zinc, copper, chromium), and other toxics. Management practices for retrofitting should be selected to remove the most cost-effective quantity of the pollutants that have been shown to cause the local receiving water quality problems. Note: Table 1.3 can be expanded to include any new practices or modifications of existing practices. Also, Appendix F (which includes a brief description of each management practice listed in Table 1.3) and the Resource Directory (which lists pertinent literature) may help the user understand and select the best management practices. a. Choose retrofit strategies. Combine the results of the two evaluation procedures. The results become the retrofit strategy for urban areas in the analysis area. The strategy should include: o Categories and specific management practices recommended. 49 � Locations of existing management practices recommended for retrofitting and the approximate drainage area treated by each practice. � Approximate locations or areas where new management practices are recommended and the approximate drainage area treated by each practice. � Special conditions or characteristics that can affect implementation of the strategy in the analysis area. � Estimates of the relative costs of management practices. The ability to estimate costs depends on the amount of information available, level of detail of the retrofit analysis, and adequate information about costs. � A summary of possible opportunities for retrofitting that require more information before including in the retrofit strategy. An urban water quality retrofit strategy developed for an analysis area's urban lands does not represent replace engineering analyses for determining the use of certain practices. It is a preliminary analysis of the potential for applying one or more practices. If later engineering studies show that a specific practice cannot be applied or should be modified, disregard or modify the strategy. C. Repeat Steps 5, A and B for applicable analysis areas. After completing the retrofit analysis described in Steps 5, A and B, repeat for all applicable analysis areas in the priority watershed. Result of Step 5 1. Retrofit strategy for the urban lands in each applicable analysis area of the priority watershed. 50 C@ C=I Pa C'Iw 1w <D C-., =r ts w 4D CD w M, w -CA CA CD m m =2 PC -C3 C, w W iw w n t= c- t, '.1 IV It m + 0 0 Wldlfe 4- 1 0 Recrea 0 0 0 0 0 0 Therml 0 0 0 0 0 0 0 L. Flo Grdwtr 7m C- -V 4- 4- 4- -4- + Dnstrm + + -4- 0 + + Health 4- 0 0 0 + + Safety 4- 0 -4- 4- 4- kesthe G 40, =r C=F 10 :k CD w I Ij" -Amk Munici commun Privat Privat cl. t=y pa s. lw (D c, cv 0. m c-. -a cD c@ a# C3 t@ r@ m ca -0 w t3- su fo op = "nk c cl. =3 co w =5 ap 12 w c, co (D w el c3 to ar ar C3 su m m ;w w m := , =1 co m vo m to ap c@ W =1 -Cl R, Cr C@ ou m Is It=$ Cu m m m c@ = - t3l- c@ t:,- 9@ =r to "I (D =2 CID co CA cp CID ap w su =3 =2 =3 'I w t3, ch ,u !n m .t3 m =3 C@ "I co P, 'D M SU w S. --a m L- - . 11 " :-- - c> w c. w 09 - C@ -. - Ic i@ ! " - @c 1-11 c@ 1-1 w c@. c) m m =3 m m m to .4 m " t= C@ M m m " m up C-- -Cl CD = It lo C@ c> Cl t= ou w " co CD sa@ to -- = -- is C. S@ ta t@r w w M c, M %. .4. kw co m - %= M I a IrD c@ cp cD CF, -4 "1 S= 4@ c@ $- t@ a) c. Irp w t@r c) 'c' tv cx. .0 ol 'In a) Z CD :- c@ CP w lu l. 1@ me "I ap It. W In w -4 W 1@- c, no VD me =3 o C, CP sm m CD Z cl. =r g@ ;a " -Q " 'o c@ Rl w p m C@ cl m w cl C@ c@ " c. c@ m m .4 m m CIP s. " ,- r p 2o m ". " w VP w w CAw jo - !, !-- .!- N lp . cm c@ to cs 0 0 0 0 0 0 0 vc 0 0 0 w ck. (D .d:a 0 E) to cD t=o a) 0 0 E) to so so ow M m1w, 0 0 0 0 0 0 0 0 0 0 0 Table 1.2 Erosion Control Management Practices. Stormwater Runoff as an Erosion Cause A. See Urban Stormwater Runoff Management Practices in Table 1.3. Sheet Erosion A. Mulch (temporary control) B. Permanent Vegetation (grasses, sod, shrubs,etc.) C. Contour-Wattling * D. Contour-Brush-Layering (green branches or rooted cuttings) * E. Reed-Trench Terracing (Reed grass) F. Brush Matting * G. Live Staking (sprigging or willow staking) H. Revetments * � riprap o articulated, precast o gabion mattresses concrete blocks � rubber tire networks o cellular grids � sand-cement sacks Rill and Gully Erosion A. Check Dams o porous - rock, brush, posts o nonporous - concrete, sheet steel, wet masonry B. Live Staking C. Regrade Site and Plant in Permanent Vegetation D. Structural Protection � revetments � toe - walls o retaining structures Steep Slope Erosion A. Toe - Walls � rock breast walls o welded-wire walls o gabion walls o reinforced earth � crib walls (timber or concrete) B. Retaining Structures o gravity walls o gabions & welded- o crib or bin walls wire walls o reinforced earth o pile walls o cantilever & counterfort walls o tie-back walls C. Revetments (armoring) * (see sheet erosion section) Note: See Gray and Leiser, 1982 for detailed explanation. 53 Table 1.3 Characteristics of Urban Retrofit Management Practices. P*YSICAL S)T@ CCA)ZV776A)SIREQU, EMEV-7@ 7** SosL sa, L C6@p,,!@, Bedrock HA@h &*.Wul -N 0 VO N N N %,9 1 1 \9 @j Ci H P- N 0 \,9 A e, A 0 ^ 0 A A Infiltration Dry Well 0 1 0 0 0 0 0 000 00 0 Trench: 0 () 0 0 0 0 0 000 000 o Full Bxfiltration o Partl. Effiltration o WQ Trench Basin: 040 00 0 0 000 1690 o Full Exfiltration o V/ Detention Basin o Off-line Trench Porous Paveient: 040 00 3 0 040 000 o Full Exfiltratioa o Partl. Exii1cratior o Water Quality Modular Paving 640 00 0 0, 049 000 Infiltration/ Grassed Swale 1 040 00 (3 0 049 640 Filtration/ Flow Attenuato. Grassed Filter Strip 0 (1 0 0 0 0 0 0 (b 0 0(3 0 Trapping Water Quality Inlet (oil 6 Grit Separator 0 1 0 0 0 (DO 04 0 Storage/ Parking Lot Storage 0 0 0 0 0 000 00 0 Release Dry Pond 40 0 0 0 0 000 so 0 Extended Detention: 0 0 0 * 0 000 00 0 o Dry Pond o Dry Food w/ Marsh o Wet Pond Wet Pond: 0 () 0 0 0 4 0 000 000 o Wet Pond o Wet Pond w/ Marsh o Wet Pond v/ Foreba Xatural Systei Shallow Marsh 0 (3 Is 0 0 0 0 040 004 Physical $and Filter 9 * 0 0 (1 (3 0 ()(39 940' Treatient, Swirl Concentrator/ 0 0 0 0 0 0 0 (1100 0 (3 31 Helical Bead Plate/Tube Separator 9 0 0 0 0 0 0 000 0 Screens 0 * 0 0 40 00 4)(34 Pfd4C77ck@- 0 Sit/ 0 54 Table 1.3 Characteristics of Urban Retrofit Management Practices continued. FIOSICAL 5/7@ C6A)Z177.OA)SAZQj1,eEM57073-- ce;5t ......... MAX. Apphc6. ble CM % uirzJ ance 9734 A - rV1 -ypq 4_1a-lsif hc V) N Infiltration Dry Well A V -Al *0 0 0 0 0 0 (3 0 0 0 0 () 0 Trench: 0000 0 0 lb (b 0 0 0 0 0 0 o Full Exii1tration o Parti. 8xii1tratior o WQ Trench Basin: , 00 0 cl 0 00(3 0 0 C) 0 00 Q Full Extiltration o w/ Detention Basin o off-line Trench Porous Paveient: 0* 0 0 0 0196 00(30 00 o Full Exii1tration o Partl. Exfiltratior o Water Quality Modular Paving 0 0 00(3 0400 00 Infiltration/ Grassed Swale 00 10 0 004 ()(100 00 Filtration/ Flow Attenuata. Grassed Filter Strip 900 3 0 0 0 1 (3 0 0 0 0 Trapping Water Quality Inlet 00 jOil & Grit Separator 0 0 0 0 0 0 0 0 0 4 0 Storage/ Parking Lot Storage *1 0 0 0 0 0 0 0 1 0 0 3 0 Release Dry Pond 00000 4000 0 000 00 Extended Detention: 00 9 0 0 0 0 9 0 0 0 0 0 o Dry Pond o Dry Pond YJ Marsh o Wet Pond Wet Pond: 00000 0 0 (3000 C) 9 o Wet Pond o Wet Pond v/ Marsh o Wet Pond w/ Forebay Natural Systei Shallow Marsh 00046 0 0 1 * 000 00 Physical Sand filter 000(30 0410 0 (3 0 C) 00 ?reatient Swirl Concentrator/ 0041310 0 * 0 41000 09 Helical Bead Plate/Tube Separator 009110 0 * * is 000 0 Screens 00040 000 0 000 00 0 RP)D@IC4611_ N47- A)O 55 Table 1.3 Characteristics of Urban Retrofit Management Practices continued. rn4A)A e5a-rnAW7_ CA ?A BII-17Y QU,4L/7-? z Y) Vo ju L Infiltration Dry Well 0 0 0 0 0 0 Trench: o Full Exfiltrati 0 0 0 0 0 0 3 0 40 0 loll o Partl. Extiltration 0 0 0 0 0 0 0 3 3 o WQ Trench 0 0 0 0 0 0 0 C) T 0 Basin: o Full Effiltration 0 0 (3 0 0 0 0 3, 3 0 0 0 o V/ Detention Basin 0 0 0 0 0 0 * () (11 0 0 40 o Off-line Trench 0 0 0 0 0 0 0 0 (1) CD 0 3 0 Porous Paveient: o Full Exfiltratio@ 0 0 (3 9 * 0 0 3 o Partl. Extiltracion 0 * (3 0 0 9 0 0 0 CD 9 0 o Water Quality 0 C) 0 0 * 0 (D Modular Paving 0 0 0 0 0 0 Dfiltration/ Grassed Swale CP 0 0 o () 0 00 0 0 0 0 iltrationt low kttenuatn. Grassed Filter Strip 1 0 0 '4 (3 0 00 0 0 0 0 rapping Water Quality Inlet 0 0 0 0 0 0 CD -0 0 0 CD 0 (Oil & Grit Separator storage/ Parking Lot Storage 0 0 0 0 0 0 Release - Dry Pond 0 0 0 0 4 T 0 0 0 0 Extended Detention: o Dry Pond 0 0 0 0 0 0 CD 0 CD C) CD o Dry Pond w/ Marsh 0 0 0 0 0 0 o Wet Pond 0 0 0 0 0 0 0 3 0 (1) Wet Pond: o Wet Pond 0 0 0 0 0 0 03 0 CD 3 CD o Wet Pond w/ Marsh 0 0 1 0 0 0 o Wet Pond w/ Forebal 0 0 1 0 0 0 Natural Systel Shallow Marsh 0 0 0 0 0 0 Physical Sand Filter 0 0 0 0 0 0 0 * (D (1) CD 0 0 Treatient Swirl Concentrator/ 0 0 0 0 0 0 1 0 0 3 Helical Bead Plate/Tube Separator -0 0 0 0 0 0 1 Screens 0 0 0 0 0 0 0 (1) 0- 5 44 n dM- CZI@ t I n zg, - LAisi-y'n Cor7c6-hartsr - 0- :: C) - hio NA - A16Y- 4PR/'C,41@m 56 Table 1.3 Characteristics of Urban Retrofit Management Practices continued. EA) VIRONI"ACA17A 1. DVRAd__r_5 A)ATU /Z4 I- HOInAAJ -4, tz %4@ V I _@j Infiltration Dry Well 0 0 0 0 + 0 Trench: 0 0 0 4- 0 + 0 o Full Exfiltration o Partl. ftfiltration o WQ Trench Basin: + + + + 0 0 0 o Full Extiltration o w/ Detention Basin o off-line Trench Porous Paveiient: 0 0 + + o -4- o o Full Bxfiltration o Partl. Exfilcration o Water Quality i Modular Paving 0 -+-+ 4- 4- 0 0 0 l,lilt,,Iio,l Grassed Swale 0 + 0 0 0 0 0 0 0 + Filtration/ Flow Attenuato. Grassed filter Strip o + 0 + 4- + 0 0 0 -4- Trapping Water Quality Inlet 0 0 (Oil & Grit Separator' 0 0 0 0 0 0 0 0 - ---------------- Storage/ Parking Lot Storage 0 0 0 0 + 0 - - Release Dry Pond - o o + o o -4- 0 - Extended Detention: - + 0 4- + 4- 0 - o Dry Pond o Dry Pond w/ Marsh o Wet Pond Wet Pond: - + + + 0 - o Wet Pond o Wet Pond w/ Marsh o Wet Pond w/ Forebal Natural Systei Shallow Marsh 0 0 + -4- 4- 0 - Physical Sand Filter _'0 0 0 0 0 0 0 0 Treatient Swirl Concentrator/ 0 0 0 0 0 0 0 0 0 Helical Bend Plate/Tube Separator 0 0 0 0 0 0 0 0 0 Screens 0 0 0 0 0 0 0 0 0 =/77 P,4 C_ 7M@ szna.7r, r-L.1 Zm P,1 Its Ne-ulr. t e, AAD t I ile TMD aets@ 57 Table 1.3 Characteristics of Urban Retrofit Management Practices continued /W,4 / A) 7-eAA AIC,5 Q 4, ky'-/ irt U t'@z -tv V, Q infiltration Dry Well b, 3 ck (.t 0 0 * 0 0 0 Trench: 0 0 0 0 0 S 0 Full Effiltration o Fartl. ftfiltration o WQ Trench Basin: 0 0 0 0 0 0 o Full ftfiltration o V/ Detention Basin o Off-line Trench Porous Paveient: 0 49 o Full Exfiltration o Partl. Zxfiltratiu o Water Quality Modular Paving 0 0 Infiltration/ Grassed Swale Filtration/ 0 0 flow Ittenuato. Grassed Filter Strip 0 0 0 Trapping Water Quality Inlet (Oil 6 Grit Separator) 0 0 0 Storage/ Parking Lot Storage Release Dry Pond 0 0 0 0 0 0 0 0 0 0 Extended Detention: 0 o Dry Pond o Dry Pond w/ Marsh o Wet Pond Wet Pond: 0 0 S7 o Wet Pond o Wet Pond w/ Marsh o Wet Pond w/ Forebaj latural Systei Shallow Marsh 0 Physical Sand Filter 0 F ?reatieDt Swirl Concentrator/ Helical Bead 0 0 F Plate/Tube Separator 0 0 0 0 F Screens 0, 0 0 See AUAL + for a summary of relative capital and 0 M costs* F- Fre S - S 7'j 0- g cia@" A.Mt-Appll colle-, &J - Nd-M@-_ Table 1.4 Urban Stormwater Runoff Management Practice Costs. Practice MaDagelent Costs Function Practice Capital Operation & Maintenance interception Urban Forestry Preserve Trees = Low Low Seedlings= S100-200I acre Saplings 51000- 5000/acre Infiltration Dry Well Trench C z 26.6 ISS11.63 1 Total = 5 to 15% 2 C Basin C = 10.11 t VS-0.69 Total = 3 to 5% z C Porous Pavezent Variable Routine ( Pond C Non-routine ) C Modular Paving C= SI.55/sq. ft. (197P Low Infiltration/ Grassed Swale Cz S4.50 to S7.75ilinear Foot Filtrationi Flow Attenuata. Grassed Filter Cz @1,49 ;hyroseW Low Strip - 910,900 Isodl i acre Trapping Water Quality Inlet C2 $5,000 to $15,000 Low iOil k Grit Separatorl Storagei Parking Lot Storage Cz estizated low over conventional Low Release Dry Pond Retrofit) 52,000 Extended Detention C 1.25 & 110.71 % Vs-1.69) Total z 3 to 5% a C Wet Pond (_(111k cu.ft.1 C 1.25 a t6.1 Vs-1.75) Total = 3 to 5% x C 0111k cu.ft.@ C 1.25 4 ;34.0 vs-1.64) Natural Systell Shallow Marsh Planting C = $1,000-3,000/acre Low Physical Sand Filter Moderate Treatient Swirl Concentrator/ C = S4,500/ind Moderate Helical Bend Plate/Tube Separator C z S2,000/acre drainage area Moderate Screens C z S19,001/nd Moderate - High - ----- - ------- Sources: C = Construction Posts in 1985 S. a MVCOG, July, 1987. c Tourbier i Westiacott, 1981. Vs z Storage Voluie of Void Space tfor Iniii. Trench). b Md. WRA, 1985. d USEPA, July 1979. Vs = Stg. Vol. up to crest of eaer. spillway (basin k pond). 59 Step 6 A Synopsis Assemble and Implement Urban Retrofit Plan A. Assemble Retrofit Strategies. B. Assign Order of Implementation. C. Implement the Urban Retrofit Plan. 60 Assemble and Implement Urban Retrofit Plan A. Assemble retrofit strategies. Assemble the strategies developed in Step 5 for applicable analysis areas into a single document. The individual retrofit strategies become part of the Urban Retrofit Plan for the priority watershed. A local jurisdiction with more than one watershed can combine individual watershed retrofit plans into a comprehensive plan for the entire jurisdiction. Most retrofit strategies will require management practices intercepting drainage areas of varying sizes. Under certain conditions however, a management practice is better applied to areas larger than a single analysis area. Examples include pollutant source controls such as solid waste management, street sweeping, leaf collection, domestic animal waste management, and urban forestry. B. Assign order of implementation. The second component of the Urban Stormwater Retrofit Plan is a schedule of implementation. At least two methods of developing an implementation schedule are possible: 1. Implement retrofitting according to the analysis area urban pollution potential ranking from Worksheet 1.6 (page 31) in Step 3. For example, all management practices in highest ranked analysis area would be implemented before addressing the next highest ranked analysis area. 2. Implement all management practices that meet specific criteria. The user selects the criteria based on the resources, needs, or priorities of the local jurisdiction. Examples of criteria include � measures with the lowest capital and maintenance costs. � measures with the highest removal effectiveness for one or more specific pollutants. � measures with a defined level of pollutant removal at a minimum total cost. � measures with the lowest social and environmental impacts. 61 C. Implement The Urban Retrofit Plan. Implement the Plan by the following four actions: 1. Verify that each proposed management practice can be used or constructed at the desired site. Develop the necessary site plans, specifications, and costs for construction and operation. For any measure that requires construction, such as an extended detention basin or infiltration device, the site must be investigated and found to meet local and state requirements. If the site is suitable for the proposed device, construction plans and specifications should be developed and construction and maintenance costs should be estimated. If the site does not meet the requirements, perhaps the retrofit strategy can be modified by altering the conditions for application of the management practice or proposing a different measure. 2. Verify that suggested source management practices, those not requiring construction, are legally and administratively acceptable. Check for duplication in existing government programs. Estimate the costs to implement these control measures. Consult the Resource Directory (page Res-1) for detailed information on estimating costs for implementing the retrofit strategies. 3. Estimate the total costs for implementing the Urban Stormwater Retrofit Plan, identify funding sources, and obtain funding. Funding sources may include one or more of the following: o stormwater management utility user fees; o Chesapeake Bay Critical Area mitigation fees for required offsets; o state or local special bonds or both; o Federal and State Chesapeake Bay Initiatives funds; o Federal Clean Water Act appropriations; o private (individual or organization) funds or corrective actions; o annual state and local funds for public works, capital project construction, and maintenance. o related Federal, state, or local government program funds. 62 4. Implement the Urban Stormwater Retrofit Plan for the Priority Watershed or, in the case of several watersheds, the local jurisdiction. Results of Step 6 1. An Urban Stormwater Retrofit Plan for the priority watershed. 2. If a jurisdiction has more than one watershed, combined Urban Stormwater Retrofit Plans for the entire jurisdiction. 63 Part 11 The Method Applied TKI 64 INTRODUCTION The following example is an application of the Urban Retrofit Planning Method to Anne Arundel County and the Magothy River Watershed. It shows the results of applying the method to a watershed with extensive developed areas and stressed receiving waters. Anne Arundel County is located on the western shore of the Chesapeake Bay, in the Atlantic Coastal Plain, south of Baltimore City, Maryland. It is bounded on the west by the Patuxent River and on the east by the Chesapeake Bay. With the county topography varying from flat to rolling, a large number of small streams in eight major drainage areas provide good surface drainage. The Chesapeake Bay's tidal estuaries penetrate as much as 13 miles inland and form a series of peninsulas with irregular shorelines and tidal marshes. In a number of places, the estuaries are shallow. Stelp 1 -- The Priority Watershed Anne Arundel County's drainage areas are shared by three Maryland Subbasins. These are: (1) the Patapsco River (13-09), (2) the Patuxent River (13-11), and (3) the West Chesapeake (13- 10) - a collection of small rivers and creeks draining directly to tidal waters of the Chesapeake Bay. The major drainage watersheds of Anne Arundel County were mapped and are shown in Figure 2.1, page 66. The basic physical, water quality, and socioeconomic information was collected for each watershed and is summarized in Table 2.1, page 67. Scores were assigned for water quality, watershed priority, the percentage of urban land, and population density and also listed in the Table. Total scores were summed from individual scores for each watershed. A review of the total scores in Table 2.1 revealed four watersheds with the highest scores: Patapsco-Tidal (15), Magothy River (12), Little Patuxent River (12), and Patapsco- Nontidal (11). Any of these watersheds could be selected as the priority watershed to study first. The Magothy River Watershed was selected the priority watershed in this example because 0 a good database of land use, water quality, and other information is available. 0 the estuarine water quality and aquatic resources are stressed. 0 the level of public and local government interest is high. 65 Figure 2.1 Watersheds in Anne Arundel County. BALTIMORE CITY .4 c"D PATAPSCO RIVER 4p \ 0- 1- - MAGOTHY It# RIVEN A qp6,- -, @# 1A +400 SOUTH RIVER ANNAPOLIS LEGEND -DRAINAGE AREA BOUNDARY 0 N CITY OF ANNAPOLIS \/'RHODE RIVER PATUXENT EST RIVER SCAU 114 SOLIS HENNING DAY DEALE CALVERT COUNTY 66 mm mm====== mm M @ @ Table 2.1 Comparison of Anne Arundel CounLy Watersheds. Juri-Miction Name.-Anne PnrpJc-I Cccrity Date- I O/ I 7 I. D. SFIM 1-btcrsheJ Name Total Urban Urban @ItrfM. P-3pultri. @Itr. Qual Htr-sFPj, Urban Ds-,@'Is i t y Total fir ez: Area L.-Brpi I P-IP-11tri 2 Evalutn. Priwity Land scs@rq (Fkres) (flerc.-D (.11) ( F-)-'35 ) Se-ore 3 -1 'S"Cr-r@, (2) (3) (@4) (5) (7) (8) (9) (10) (11) Pat,Vsco-T i da 1 2219-c- M- 151-955 E-1 1 0-i'6168 4 z I EI 5 15 P&ar-sco-H M-t ida- 1 11669 6651 57 235Q 2 3 1 S 2 1 1 i. -'I Brdin Cred-, 5M 2103 31? 68:33 3 1 2 MagothL S .1 River 22.751 11607 51 5594I --.4 939- 05 1.6 :3 1 -.3 dNvm Pi ver -32,559 1 "294 '( SjAh River '3451 LI 8 9 73 26 3,38,59 13.-7 1 2 1 Ph-j-50 River Ml) 12414 1 40,11-1 0.5 :3 0 1 1 5 Hs;sA River %.-r[4 9,36 I? 13.6 0 1 1 Herring Bay I 1 5 5.2 23 1 0 20 0 '(2 7 0-113 0 Patuxent River 47411 616-11 13 16143, 13.3 1 1 1 Little Patuxent P. 281 12 113116 E-8 16851 I.? 3 1 El TOTALS 23---288 I 06- 7139 357(19-3 l Total Urb@n includivs Rresi&M-ial - 1, 2,5,& 15-22 (ILVAC.. c!JMwr-cial, @ 11 Marijard Water-4ird Price-ity L.i2;t (19,06). Industrial Lands. 2 Popilation estimated by ow-clayinq watersheds. tran-zriortation zones, & -xw- sqrvice areas and known pc@pelation count5. 3 Maryland Subbasin & Segment I-Iater- Quality Evaluation@, in 1986 305(b) Report. Step 2 -- Analysis Area Characteristics Defined The Magothy River Watershed has a land area of approximately 31.5 square miles. A watershed of this size can be analyzed adequately using a map scale of 1 inch = 2,000 feet. Information obtained about the watershed included: 0 Land use/cover inventories - available on recent (1984) aerial photography at a scale of 1 inch = 1,000 feet. 0 Topographic maps - available at several scales including: U.S. Geologic Survey maps at 1 inch = 2,000 feet and County topographic maps at 1 inch = 1,000 feet and 1 inch = 200 feet. 0 Maps of water and sanitary sewer service areas in the County Water and Sewer Plan. Several levels of drainage area scales were available for possible analysis areas. See Figure 2.2, page 72, for four types of drainage area in the Magothy - the watershed, creekshed or subwatershed, subcreekshed, and storm drain system catchment. Based on the size of the watershed, the resources available, and the drainage patterns, the analysis area scale chosen was the subwatershed or creekshed. If a smaller analysis drainage area were selected, more detailed information would be required and the costs of analysis would increase. In Figure 2.3, page 74, the drainage boundaries of the 18 analysis areas selected for the Magothy River Watershed are shown. These areas are defined topographically from the 1 inch 1,000 feet scale maps provided by the county. The analysis areas range from 311 acres each for Broad Creek (4) and Spriggs Cove (14) to 3,390 acres for the Upper Magothy River (8). The analysis areas generally are numbered counterclockwise from the Otter pond drainage area on the north shore and are named by the creek name or community name. A planimeter was used to derive the physical characteristics of the priority watershed and each of the 18 analysis areas (see Figure 2.4). The characteristics are listed in Table 2.2, page 72. The methods used to derive the characteristics appear in chart form. 68 Figure 2.2 Alternative analysis area scales. % %% % % '00 4J. % Jw @.q If dF %0 )-,."% Magothy River Watershed Anne Arundel County, Maryland (Level I Drainage Area) Creekshed (Level II) Subcreekshed (Level III) Storm Drain System Catchment (Level IV) Figure 2.3 Analysis area boundaries in the Magothy River Watershed. 100, LEGEND No. Name 1 otter Pond 2 Cornfield Creek 3 Grays Cr. moo 4 Broad Cr. 5 Blackhole Cr. 6 Ross Cove 7 Cockey Cr. 8 Magothy River (Upr) 9 Lk. Waterford 10 Cattail Cr. 11 Cypress Cr. 12 Dividing Cr. 13 Mill Cr. 14 Spriggs Cove 15 Forked Cr. 16 Bayberry 17 Deep Cr. 18 Ltl. Magothy R. J "00, A,,OO Y MA 490 V A 00 LEGEND WOODS THICK wOUDS, THIN RESIDENTIAL 1/4 AC RESIDENTIAL 1/0 Ac. URBAN - COMMERIAL URBAN - INDUSTRIAL ROW CROPS - STRAIGHT FALLOW - BARE SOIL OPEN SPACE Figure 2.4 Land use map of th* Magothy River Watershed. mill Table 2.2 Magothy River AnalYsis Area Information. Priecr itu Water'-f*d- Mvpthy River (firw* Artw6el County, Mwylarvl) I -if I latal MatkAw4 FiriT- 22522 ALrq--. M--n I.And Arem. By %--e I i4v I Claru- of P.4c*iving W. P@@; 9bwtrsM AM14pis firea, LY4 Area Urban Haw NO Nw Awlysis Fir ea Oot !.izr) NO. Ar ea Pr iorij. Pr iery. 15,cecnoin4. Sq,-jn-Jrq. (A.Yre) (FirrQ) 2 Acrv I A..r-p 1 1 Q k--. 1/4 PO-, P.3 C, .", lroku. ln@Ait- Otlw@ Itpe clw!. Tq:w cl @@s (1) (41) (3) (4) (5) (6) (9) (10) (11) 1* 12) (13) (14) 15) 161) (17) (18) 091 Ottcr PoW I i !A9 395 131 0 1 Al. 9 0 0 1) 1 1 3 11 Cornfield Cri-cV. 1 MV 634 0 1@77. !3 0 0 f If. j. 1 1 1 3 11 Gramp Cr. 3 ?U 307 0 0 0 3 If grxd Cr. 4 311 124 44 RO 0 0 13 3 11 Blact-Me Cr. S 7? -c 142 0 141.6 0 0 0 0 11 Pass COW 6 286 115 1) 115.2 1) 0 11 1) 3 11 Cc4.Qy fr. 7 islet, 897 0 0%. 8 0 0 0 0 1 1 3 11 Kage" 1&-. (Upr 8 33% 15% 0 ic". 9 13 83 13.(i 1) 1 1 3 11 U. W-tcrford 9 2915 1 k-A 0 fill-A 0 6A. 9 F.14. 6 0 1 1 2 1 Cattail Cr. 10 078 13M 1) L%: 11 0 :39.5 41.1. 1) 1 1 3 11 Ckpr ce-- s Cr . I 1 063 "2 0 726. 4 0 q). " W6. 4 1) 1 1 3 11 Dividinq (r. 12 1076 463 0 417( 0 22 1 1) 1 1 3 11 14 ba Nil I cr, 13 1170 617 0 0 75. 3 90.2 11 1 1 3 11 Spri%s Cow M 311 287 0 0 1) 1) 1) 1 1 3 11 Forl;ed (r. 15 8r16 435 0 166. 7 84.5 45. '4 1. 37.7 1) 1 1 3 11 Bayberry 16 504 24@) 1) ZA8 0 0 1) 0 1 3 11 DeW Cr. 17 1349 853 0 62N. 4 201.4 24'. 8 0 11 1 1 3 11 L. PlagotNj P. 18 1?45 1085 0 M 1, 2 V. I ;L 1 0 131 1 1 3 11 701FILS 22522 115M 44 10091, 5 318 1ro 3 4,14. 9 Pt Derivation of Analysis Area Characteristics Characteristics Source Method Area of priority Map Planimeter watershed Area of analysis Map Planimeter area Mylar sheet Area of urban land overlay on Planimeter according to use Aerial Photo (111=1,000') Urban land area Individual Urban Sum of indivi- in analysis area Land Uses dual land uses Stop 3 -- Analysis Areas Ranked by Pollution Potential A Composite Runoff Coefficient was calculated for each analysis area using the land uses in Table 2.2 and estimated percentage imperviousness values. An example of the calculations is included in Table 2.3, page 74, for the Deep Creek analysis area. The results are shown in Table 2.5, column (12), page 81. The soils in the Magothy River Watershed with moderate, high, and very high erodibility (K = 0.32, 0.37, 0.43, respectively) were defined by tracing the soil mapping units with these characteristics on an overlay of the Anne Arundel County Soil Survey map sheets. The results are shown in the map labelled Figure 2.5, page 75. This map overlaid on the land use map (Figure 2.4) resulted in the map presented as Figure 2.6, page 76. The results were summarized by analysis area in Table 2.4, page 77. Using the Anne Arundel County Soil Survey maps and the Natural Soil Groups classification system, soils with moderate (s = 8-15 or 10-15 percent) and high (s >= 15 percent) slope ranges were mapped. These soils are shown in the map, Figure 2.7, page 78. The map was then overlaid on the land use map (Figure 2.4). This overlay is presented in Figure 2.8, page 79. These results are also summarized in Table 2.4. 73 Table 2.3 Deep Creek Analysis Area Composite Runoff Coefficient. Priority Watershed Mct!z&-M@l I var Date /,0/87 Analysis Area No. 17 Name DV @ Use of Land Area of Percentage Land Use Impervious Col-(2) x Col.(3) Area Value (Acre) (Acre) (1) (2) (3) (4) Residntl. 2 ac. Resid. 1 ac. Resid. 1/2 ac. Resid. 1/3 ac. Resid. 1/4 ac. 608-4- 38 Z3 87-9 Resid. <=1/8ac. 2o C) e) I Commercial Industrial Institutional Other Urban Land All Other Land Total 134:9 Weighted Percentage Total col.(4) Impervious Urban Land in Analysis Area Total col.(2) Composite Runoff = 0.05 + 0.009( Wtd. Pct- Imp. Area) Coefficient (Rv)a = 0.05 + 0.009( 0-S Transfer Rv for each Analysis Area to col.(12) in Analysis Area Pollution Factor Worksheet. a source of equation: MWCOG, July 1987. 74 WOW NOTES: o Erodoble Soil Ranges from USDA-SCS Soils Survey of Anne Arundel County. o Soil Erodibility Categories combined: Figure 2.5 Erodible Soils in the Magothy River Watershed NOTES: Ar o Erodible Soils from USDA-SCS Soil Survey of Anne Arundel County. Figure 2.6. Land use map overlaid on erodible soils. Table 2.4 Magothy River Analysis Area Erodibility and Slope Factors. Priwity MatersVred- Ii:tgothq Riw-r Watc,rshcni fit-mr. fir-lin-R4 Countq Maryl.@nd I.D.: ubwatershp-d Rna I ys i n- Ar-e; Law-I Arca I-Vb-in Urbn Area Urb=m Ilrbn FIrc,= Urb.5n of firq,-@ ewer Er,-Ib I t y, 1)*V";,r S lope of No. Nl="D,;, fInaIq5:i5 Er-k-Able. Pat i,@ Mod./-c"tp. L.-F-rid 1:5 Pat.L'O Are; C53 i h; (ficrq5) (Acres) (7) (1) (21) CI) (4) (5) (6) (7) (-1) 9) Otter Porp-I I 5-N11C, 395 131 69.9 513.31 2.6.9 11).53 CLvmf ir-Ad CrKlf. 2 15'327 I@N V-3-1.1-3 27.. 46 75.1 10,I)IR Arcog, Cr. 3 762 121.7 ?3.61 10 - 3. 45 Brnad Cr. 1 311 124 88.8 71.61 5: 7. 6 46. 45 B I ac+.ho I c- Cr. 5 7,177 M2 5?.9 140. 7? 43 @ 6 71) Ross Cove 6 2136 115 6.-17 5.8-3 '24. @? 2 1. 5-1- Cch-4-e-y Cr. 7 171.2"If 297 95.5 10.65 69 - S 7. 70 Maqoth@g R. (Upr. 8 3-330 1 a,6 61.5 :3.:@q 180-1 11. Lk. WatRrford 9 2-915 1251 74.4 5. 9__@ 155. 9 12,13 Wlail fr. 11) 1-97h, 1309 i8q.4 14.40 7 2-41.15 Cypre5s Cr. 11 t 992 275.2 2?. N 159, 9 t 5. " 2 Dividing Cr. 12 326.z 70. @5 IN. 0 18,14 Hill Cr. I --w H70 617 423.6 68.65 157 0 29.45 IA Spriqq!; Cove 14 4Wf 100 , 113 395. 121 10 1:1 176 FukrPed Cr. 15 866 4-3.5 t 96.17 45.22 149,4 34@34 E:a,_4bs,rry t6 504 .225 92 @ 1 .03 . 9 1 13. 3.13 NNP Cr. 17 B1411 853 422.4 IM 52 2,41, :3, 4.1-, 2, 1 17,45 1 IM15 5 7. 79 L. Tcltal 2215212 t 15 0 5 7,11190 F1,471, VON A 40 -4 If -SOW NOTES: o Slope Ranges from USDA-SCS Soils Survey of Anne Arundel County. o Slope Categories combined: Figure 2.7 Slope map of the Magothy River Watershed. dL Ali -f--j I-TI ri it AV k V. k St V Slope map from USDA-SCS Soil Survey of Anne Arundel County. 41 40 Ir Figure 2.8 Land us* map overlaid on slope map. Using the Magothy River analysis area information and maps and a planimeter, data on pollutant factors were obtained. The tabulated data for each of the 18 analysis areas are shown as ratios W in Table 2.5, page 81. The table also includes the composite runoff coefficients, urban area over erodible soils, and urban slope of land ratios taken from Tables 2.3 (page 74) and 2.4 (page 77). Each of the pollution potential ratios in Table 2.5 were, for illustrative purposes, assumed to be of equal significance and assigned weights (W) of 1. An evaluation factor (F) is equal to each ratio (R) multiplied by a weight W. The Pollution Potential Scoring Matrix (Table 2.6, page 82) for the Magothy River is organized by the 18 analysis areas. The pollutant potential factors developed, each have been converted to rankings for all 18 analysis areas based on each factor's magnitude. A rank value of "1" represents the highest rank and "18" is the lowest. Note that the composite runoff coefficients are equal for Grays Creek and Ross Cove. In the ranking process, without a tie, one value would rank 14 th and the other one would rank 15 th. Because a tie exists, both analysis areas are ranked 14.5. Note that the lowest factor score represents the highest pollution potential. The assignment of weights to the Pollution Potential Factors in Table 2.3 will influence the ranking. Each evaluation factor in the Magothy River example (Table 2.6) is assumed to have an equal influence on the pollution potential. An example of unequal weights is shown in Table 2.7, page 83. The Composite Runoff Coefficient has a weight of 2, and the Erodibility of Soils and Slope of Land ratios each have 0 weights. In the Magothy River Watershed example, only one unusual pollutant source is noted. No Field assessment was made. However, according to several concerned citizens an automobile "junkyard" located in Cypress Creek (adjacent to tidal waters), is exposed to rainfall-runoff. This source can generate pollutants, some of which are toxic. A "+" sign is placed in Table 2.6. 80 Table 2.5 Magothy River AnalYsis Area Pollution Factors Matrix. P i-rib.4 tkbm-Awl- Hapthy Rivcr (Rnr* Arundrel rrd,,ntj NAryl-@rki) Er,:-!ibilit:@4 Slope UFO.M. V-01p PV of of Land th. Nw P. N F p It F R N F P w F p N F Q) (Z) GO Q) k *d.') Q.) (1) (2) (3) (4) (5) (6) G) f 10) (11) (12) (13) (14) (15) 14;) (17) (18) (19) (20) I Atter Pond 1.14 1 1.14 33-16 1 33 16 1.@ I I. 71S, 16-310 1 16.11 %.31 1 50.31 41n.53 1 211. 53 2 Cornfield CrW: S.q5 1 5.95 44.50 1 44.4.1 A.82 1 6.132 20.40 1 20.4) 27.4c 1 27-4 V). qR 1 10.98 3 6r,-p (r. 1 2.67 40-2q 1 .01. @11 *3.'38 1 3.38 18. 80 1 1 ?1 CIO 3q.64 I -M. m 3.115 1 3.45 I Proad Cr. 1.08 1 1.08 39.87 1 39.8.1 1-:38 1 1-1-18 If;. -33) 1 16.-111 111.61 1 ?1.61 46.45 1 46.15 5 BIM-NA9 Cr. 1.23 1 1.23 18.428 1 is @ 2-9 3.4.9 1 3.45 11. 211 1 11 . 293 40.77, 1 40.?? *:N-l - M 1 .30. -70 6 PC,-.5 Cow 1.00 1 1.00 40.21 1 41.21 1.27 1 1.2.7 18. 90 1 13-90 5,q3 1 5.83 21 -57 1 21.57 7 Cr. 7. *31) 1 7M 50-420 1 CA "M 1 .7.93 22. X 1 22. X 10.65 1 10.65 7.79 1 7.78 e Naothy P. (Opir) 13.79 1 V-A. -(q 46.78 1 4c.. 7,1. 15.05 1 15. 05 '21 1 . 1 21.20 3. @11 1 3.8a It. I? I ti.37 9 Lk. NAirro-4 10.110 1 10.90 43.02 1 4MC 12. 14 1 12.94 21.40 1 21.40 S.q3 1 5. 143 12.43 1 12.43 10 Cattail Cr. 11.11, 1 11.37 646,13 1 66 13 8.78 1 8.78 29.10 1 Z4 10 14.48 1 14.49 22. 15 1 22.15 11 Ctjp-e!;:s Cr. 8.6.1 1 8.62 742 M 1 711. 9-1 6.10S 1 6. JY@ 35.40 1 35.40 27.74 1 2.7.74 15. -,2 1 15-72 12 Dividing Cr. 4.02 1 4.02 43. (n 1 43. W 4.;@3 1 4.78 21. V 1 21.33) 70.49 1 70.@6 18.14 1 18.14 13 Hill Cr. 5. 3A 1 5.36 52-74 1 5.1. 74 5. 11 1 ". lq 27. cl) 1 27. EN) Q3.65 1 09-65 25-45 1 25.45 14 *-;prigp Cow 2.49 1 2.49 92.22-8 1 '12-20 [.*kq 1 1.:,,8 :Y6 - 50 1 Irl. 9) 35. 12 1 45.61 3. 76 1 3.76 15 Forl-xd Cr. 3.73 1 1. M 50-2.3 1 50.":3 3-.39 1 3. RS :31. 60 1 11. (J) 15.22 1 45,22. :34. -14 1 34. 34 16 Baybri-ry t.% t t.% 44.64 1 44. 64 2.@,l 1 2.244 1 4@. 'i 1 1 43.91 13. 3-9 1 13. *-Q 17 De4p Cr. 7.41 1 7.41 63.7.3 1 63-23 5..je4 I - -0.52 1 4). 1512 1218 - 213 1 - 91 :31-00 1 :31. w 28. 2) 18 L. "thy R. 9.43 1 9.43 62.18 1 6.1.18 7. 75 1 7. -75 pi) '47.18 1 37.18 7. N 1 7.79 P : Patio F= EvOuption Factor H Wight F :: P x N (c-*,p Text for Calculation of Factor--@ and Height-s. ) lJOILM. Urban Ar" to llab:fAed lot-al Urban Arca Ratio M = [*@Aw-is Arra U-.w 14atQrsNA Ariq Patio LOW Orbm. Area t.-, ArelLtsis Rhea Patio Py : Cowo:ite Punoff (,-wfficient m m m m m m m m m m m m Table 2.6 Magothy River Analysis Area Pollution Potential Matrix Equal Weights. I of I Pr.iority KBtershed- Maqothy River Watw-:b@:,J Annc- flrund,;-1 (co-inty Martiland I.D.: SPIl Ana Iys i s Area Evaluation Factor R.@,nhng E va I ut.n. Doorc,-tre.3% Rec,-:ivinq UPS AH - --- --- --- - - --- --- --- --- --- --- - Factor No. Name F F F F F F Score pr i mary dr Y. , SCAPE. I C I (1) (2) (5) (6) (17) (8) (9) IC0 (11) t2_1-1 1:-,) (14) I Ott@:Y Pond 16.5 17 15 16.5 4 R 1 1 2 Cnrnf ield Cr. 8 11. 6 12 1 14 6,q I I 3 6ray-5 Cr. 12 14 t2, 5 14.5 9 11.3 11,30 1 1 3 560 I Broad Cr. t6.5 16 1.6-5 16.5 1 1 67. 5 1 1 7 4T .5 5 A Bla&,N31e Cr. 1.5 19 12, 5 18 7 6 R055 Cow 17 15 to 14. 5 t7 5 6 1 5 7 Cockey Cr. 6 7.5 ZI 13 t5 15. 9 56 1. 1 3 Go x"I 8 M&jothy R. (U@,r. 1 14 1 It I R H, 53 1 1 r -1-1, r 9 Lk. Waterkird 5 2 13 16 5A. 5' 1 1 10 Cattai I Cr. 2 3 3 1`1 6 3.1 1 2 11 CL press Cr% 5 ? 1.2 to 38 1 1 12 Dividing Cr. 10 12.5 10 113 9 5,31.5 1 1 5 1.3 Hill Cr. 9 6 9 5 39 1 _3 14 Spriq z, Cove 13 1 16.5 1 It 1-7 59. 5 1 1 2 5 9 15 Fork-c-A Cr. It 7.5 11 3 E 419. 5 1 3 1.6 Bayberry tq III 111 1:3 It 69 1 1 17 Deep Cr. 7 4 8 4 5 4 32 1 1 4 3 to L. Ngotby P. 4 9 5 5 to 15.5 4-1.5 1 1 3 :31 11. . F1 = LIRHUAR Factor F4 = Ry Fzo--tor UPS linu-sual. Pollutant S,:ajrr-z,. F2 = UARAR Factor F5 = Erodibility of Solls F&-tor F3 =- RANIRP Factor FE. =1 Stope of Land Factor Table 2.7 Magothy River Analysis Area Pollution Potential Matrix Unequal Weights. ef I D-A-c- - Priority MagAhLI River Wats-rf-hri-I Rnric, Ars.-ndc-I Courltq K-3rmland I [1. 7 '3 R. M Rnalysis firea EVaklation Factor Rarking Evalutn. Downstream Receiving H-5b;-r3 F-E,Aor No, Nw. F F F F F F Seore Pr- t tn.-:,r y Secondry. PH 0 R E 1 2 (1) (2) (3) (4) (5) (E-) (9) 10) (11) (12) H) (15) 1 1 Otter Pond 1? 15 16.5 (1 0 65 1 1 455 2 Cornfield Cr, 8 it 6 12 0 1) 1 3 6r-aLps Cr. 12 14 12.5 14.5 0 0 5 3 1 4 Br"J Cr. 16. 5 16 16.5 16.5 0 0 65. r5 3 4 5:3 . 5 i 5 Blackhols-, Cr- 15 18 12%. 5 Is 0 0 63-5 1 1 3 7 6 Ross CiNe 17 15 18 14.5 fl 13 64-5 1 1 7 4r. 1.5 ? Cml:.ey Cr. 6 7.5 0 0 25. 5 1 1 C 8 Magothy R. (Urr. 1 9 1 It 0 0 Z2 1 1 1_14 9 Lk. Waterford 3 12.5 0 1) '26 - 5 1 10 Cattail Cr. 2 3 3 6 0 0 14 1 1 2 3 7 10 11 Cypress Cr-. 5 2 7 .0 0 16 1 1 3' 7 4 11 12 Dividing Cr. to 121. 5 10 10 0 0 4-2, 5 1 1 5 13 Mill Cr. 9 6 9 7 0 0 11 1 14 Spr i gqs Covc- 13 1 16.5 1 9 0 31.5 1 1 5 15 Forked Cr. 11 5 11 3 0 0 32.5 1 1 2 3 7 -'% 16 Baybo-r-ry 11 10 14 13 0 0 9 1 1 1 I? Deep cr. 7 4 0 4 0 0 7 2 161 18 L. Matgothg P. 4 5 5 5 0 0 19 1 "1 2 Fl LFWFIR Factor F1 Rv Factor ljp,--, Unusual Pollutant scajrci-- F2 UFMR Fact-,w F5 Er--dibility of Soils Factor- F3 WOP Fact'-w F6 Slope of Lmantl Faetcw The Grand Scores from Tables 2.6 and 2.7 from lowest to highest values. The Magothy Watershed Water Quality Pollution Potential follows. Table 2.6 Table 2.7 (page 82) (page 83 ) Analysis Area Score Rank Score Rank Deep Creek 224 1 161 6 Cattail Cr. 238 2 98 1 Cypress Cr. 266 3 112 2 Mill Cr. 273 4 217 a Forked Cr. 280 5 227.5 10 L. Magothy Rvr. 308 6 133 4 Dividing Cr. 371 7 297.5 12 Magothy R. JUpr.) 371 8 154 5 Cockey Cr. 399 9 178.5 7 Spriggs Cove 417 10 220.5 9 Cornfield Cr. 448 11 259 11 Broad Cr. 476 12 458.5 18 Bayberry 493 13 357 13 Lk. Waterford 495 14 132.5 3 Blackhole Cr. 518 15 444.5 15 Otter Pond 536 16 455 17 Grays Cr. 564 17 371 14 Ross Cove 627 18 451.5 16 The ordered ranking with equal weights indicates that Deep Creek has the highest water quality pollution potential. If the erodibilty and slope are not considered important, the alternate ranking shows that Cypress Creek would be the highest pollution potential. Generally the results of both analyses indicate that the analysis areas in the western part and south shore of the Magothy Watershed are important urban pollution potential sources. This could provide a focus for the further investigations and development of retrofit strategies in Steps 4, 5, and 6. In t1vis example, however, only the Deep Creek analysis area will be used in the application of Steps 4 5 and 6. step 4 A Profile of Deep Creek Additional Information A range of additional information was available for Deep Creek including: 84 o Aerial photographs at 1 inch a 1,000 feet scale (1984). o County topographic maps with a photogrammetric background at 1 inch = 1,000 feet and 1 inch = 200 feet. o County Soil Survey Report (1973). o Information about public lands and facilities. o County land use and zoning information. o Nontidal wetland maps from the National Survey. o Detailed records of storm drainage systems. The I inch = 1,000 feet county topographic map with a photogrammetric background for Deep Creek is shown in Figure 2.9. The County Soil Survey scale was enlarged to overlay the topographic map. Using the soil survey, the following characteristics were mapped: hydrologic soil groups (A, B, C, or D) (Figure 2.10), erodibility (Figure 2.11), and slope ranges (Figure 2.12). Field Survey Given the amount of additional information available for Deep Creek and limited labor resources, a windshield field survey was performed. The entire subwatershed was covered by driving the major roads. Survey personnel used a Survey Checklist (see Step 4), a current road map, a topographic map, and a tape recorder. The recorded notes were later interpreted in developing a profile of the subwatershed. Profile of Urban Conditioas and Retrofit Opportunities The urban conditions and retrofit opportunities in the Deep Creek subwatershed are summarized in Table 2.8, page These were developed from the additional information and results of the field survey. The profile of existing conditions and retrofit opportunities for Deep Creek is the compilation of a composite of Figures 2.9 through 2.12, the results of the field survey, and the summary of conditions and opportunities. 85 MR Oro OIL% MAI ?,#,4 , va, e*, YA It f, ZOO- @j A F,10 OR ONO CO 11 MUM 162AE VAl@rnll limFlo LEGEND ilk ------------------ - - -- - --- -- mismil RIM Ell R -7. Kinor Drainage Areas Air-, '4Z 7, 1PUN -o- Drainage Pathway. Narina Source: Anne Arundel County 1'= 1,0001 tap series. Figure 2.9 Land use and topography in Deep Creek. MEND E:1 Group A Group B Group C Jmt@ 2@@ @E: Group D Source: A.A. County Soil Survey (1973). Figure 2.10 Hydrologic soil groups in Deep Creek. mom mm mm mm M mm mm mm M 'Rap- 71 co -77-- LIGRND - - - - - - - - - - - - - - - - Lov K 0.32 ............. ............. Kaderate K 0.32 High X 0.37 Very High K 0.13 Source: lane krundel County Soil Survey 11973). Figure 2.11 Soil erodibility in Deep Creek. 11% . . . . . . . . . .K . . . . . . . . . . . . . . . 00 ,,source: Anne Arun Figure 2.12 Slope ranges in Deep Creek. Table 2.8 survey results of Deep Creek subwatershed. Land Use/Covftr o Land uses in the subwatershed: + predominantly residential - mostly single family with a few concentrated areas of apartments and townhouses. + residential age ranges from pre-1950's to current development. + older residences scattered throughout watershed but concentrated near estuarine waters. + streams and floodways are heavily wooded. + tree cover in developed areas is estimated to range from 0 to 40 %, predominantly hardwoods. + commercial development is recent and concentrated along major roads, except for four marinas which are located along the estuary. Land Ownership o The majority of land in the subwatershed is privately owned. Streets and roads are public with some rights-of- way. Hydrology o Subwatershed drainage boundaries visually match 1 inch 1,000 feet topographic map boundaries. However, for a more detailed assessment, smaller drainage area boundaries may have to be checked in the field. o Imperviousness estimates based on mapped land uses are reasonable. o The overall subwatershed has the following "hydraulically -effective" characteristics: + many house roof downspouts drain to lawns. + most driveways are paved and are contiguous with the street. + curbs and gutters are located on some streets and roads - most are in recently developed and higher density communities. + storm inlets and small drainage systems are located throughout the subwatershed - most in recent developments. o The subwatershed's ground slopes are generally moderate to high. Flatter slopes are located near the tidal waters and near College Parkway in the upslope areas. 90 Table 2.8 Survey results of Deep Creek subwatershed continued. Stream valley and drainageway slopes are moderate to steep. o The typical storm drain system is composed of a paved surface (roofs, streets, sidewalks, parking areas) draining the runoff to either a pervious swale or a storm inlet. Inlets are connected to short pipes emptying to natural drainageways. Pollutant Sources and Problems o From field observations, the residential and most commercial land uses, as pollutant sources, fall within the land uses monitored in the USEPA NURP study. o The four marinas are potential sources of pollutants not normally found in residential or commercial runoff. This is especially true in handling gasoline and oils. Any spills could be washed by runoff directly into tidal waters. o Streams and natural drainageways generally show signs of gully erosion. Steep banks appear to be sloughing. Some roads without curbs show minor sheet and rill erosion. Relationship to Receiving Waters o The total drainage pathway distance throughout the subwatershed is generally less than 2,000 feet. o Receiving waters include small streams and wetlands in low areas draining to tidal waters. Runoff is delivered rapidly to Deep Creek and the main Magothy River estuaries. Retrofit Control Opportunities and Constraints o From the available information, the locations of public lands are not obvious. o Wet Ponds - a series of four small wet ponds are in the Bay Hills Golf Course along two small southwest tributaries of Deep Creek. The ponds are shallow and used as visual and recreational amenities. 0 Existing detention basin located in drainage area 17.1 (see Figure 2.9). 91 Table 2.8 Survey results of Deep Creek subwatershed continued. o Subwatorshed conditions as possible opportunities for retrofitting: + roof downspouts draining to paved surfaces. + stormwater inlets + bare foot paths + pervious areas adjacent to roads + stormwater outfalls + utility easements and rights-of-way + wooded, natural drainageways and stream valleys. 92 Step 5 The Urban Retrofit Strate;W Using the procedures of Step 5 (see Part I), the Deep Creek subwatershed was evaluated for urban retrofits. This involved comparing the Urban Retrofit Profile (see Step 4, page 90) to both existing and potential management practices. Existing Management Practices Source Controls An evaluation of management practices in use was made concerning source controls in Deep Creek urban areas. Using Table 1.1 (page 51) from Part I, existing management practices are: � No public street sweeping is performed. � The county manages solid waste collection based on the Solid Waste Management Plan (April 1983). Although the County provides routine collection services, community ?leanup, and bulk collection, other actions are needed, ncluding public education, especially as it relates to water quality and the environment. Secluded areas are posted for no dumping but may not be effective. This requires more community action. � All fertilizer and pesticide management is the land owner's responsibility. � The County's roadway de-icing policies vary with the snow and ice conditions. The policies should be closely examined, especially in drainage areas that are environmentally sensitive. o Pet waste management is the pet owner's responsibility. � No materials handling or small spill policy is in effect for commercial marinas. Erosion Controls A brief field investigation did not reveal any past erosion control efforts, other than in development areas. These appear to be adequate. However, a more extensive investigation is necessary to locate and define the types of eroded areas requiring controls. First priority should be the correction of problems on publicly controlled lands, especially along roadsides, urban lands, stormwater systems and outfalls. 93 Runoff Controls Deep Creek has detention basin in area number 17.1 (see Figure 2.9.) The basin is a candidate for retrofitting as an extended detention basin to control small storm events for water quality. Using the criteria from Table 1.3 (page 54) and a site investigation, the retrofit potential can be better defined. Four small wet ponds are in the Bay Hills Golf Course, privately owned. From drainage area maps, these appear to be located off the tributaries and function as visual and recreational amenities. Without more information about the contributing drainage areas to these structures and the physical characteristics, their potential as water quality management devices is unknown. From the Profile, most single family residential roofs drain to lawns and-appear to be performing adequately. However, some were seen in the survey to drain onto paved driveways. Also the higher density multi-family and commercial areas should be more closely investigated. For those residential areas located in hydrologic soil groups A or B (see Figure 2.10), on low slopes, with a low water table, and with adequate land area, dry wells or trenches are appropriate. Where limitations exist, downspouts to splash blocks and a vegetated buffer is an alternative. New Management Practices Source Controls From Table 1.1 in Part I, Step 5 (page 51) and the results for existing management practices, the following new source control retrofit practices are appropriate: � Street sweeping and parking area cleaning are appropriate only in the multi-family townhouse and apartment communities and commercial facilities. These are private facilities and should be cleaned privately. � The County should develop a two phase program for control fertilizers and pesticides applications. The first phase would be education. The second phase, an ordinance and regulations, would be implemented only if phase one is not successful. o Pet waste management is a private responsibility. Initial control efforts should focus on education and be targeted in areas with > 1 dwelling unit per acre. � The County should provide education to marina owners and users about proper materials and chemicals handling. Marina owners should provide proper facilities for 94 chemicals handling and disposal of waste products. Erosion Controls o The Profile and Figures 2.11 and 2.12 show that the primary drainageways and stream valleys are subject to erosion. The brief field survey revealed some current erosion, especially on steep, exposed slopes and in the channel. Where the drainageways and streams are in public ownership, appropriate erosion control management practices should be implemented. Table 1.2 (page 53) lists a range of controls. Suggested measures to retain area's natural character in protecting the slopes should consist of permanent vegetation. However, other measures such as contour-wattling, contour-brush-layering, Reed- trench terracing, brush matting, and live staking will help stabilize the slope until the vegetation is established. For gullies and severe stream bank erosion, check dams, live staking, and regrading and planting with permanent vegetation are recommended measures. Runoff Controls � A site has been identified for a possible basin (see Figure 2.13). Using Table 1.3 in Part I, Step 5 (page 54), the site is suitable for a wet pond. If adequate water is available, a shallow marsh can be added as a forebay. The structure, although not as good a water quality management practice as an extended detention basin, will also serve as a community amenity. The basin in expected to control most of the debris and sediment, moderate levels of phosphorus and oxygen demanding substances, and lower levels of heavy metals. Little nitrogen control is expected. � An area suitable for temporary storage of runoff behind a roadway embankment is shown in Figure 2.13. This area, subject to field inspection, has the potential as an extended detention structure or shallow marsh system. o Stormwater inlets, located in areas of recent development, are candidates for retrofitting. The two conversion options are: remove the bottom and infiltrate some of the runoff volume or expand the inlet into a water quality inlet which traps pollutants. � The Deep Creek Profile indicates that tree cover in developed areas ranges from 0 to 40 percent. In stream valleys, tree cover is 50 to 90 percent. The county should develop an urban forestry program on public lands and encourage private urban forestry. The Maryland Forest, Park, and Wildlife Service sales tree seedlings at low cost and is a good source of help. 95 '-**L Drainage Boundary x Infiltration Area Area of Stor-age Behind Structure Wet Pond Site Retrofit sxisting Detention Basin- Figure 2.13 Possible locations for retrofit control measures. o Drainage pathways on public lands or rights-of-way are subject to retrofitting. High priority areas include runoff from roads and other paved areas. Management practices are specific to a site and the existing conditions. However, Table 1.3 lists potential control measures. These include grassed swales, vegetated filter strips, and infiltration trenches (see Figure 2.13 for possible areas where infiltration is feasible). The management practices specified for source, erosion, and runoff control, combined with Figures 2.9 - 2.13, are the retrofit strategy for the Deep Creek analysis area. The procedure to develop the retrofit strategy for Deep Creek should be repeated for other appropriate analysis areas in the Magothy Priority Watershed using the ranks in Table 2.6. Stop 6 -- A Watershed Retrofit Plan Assemble the Retrofit Strategies A retrofit plan for the Magothy River Priority Watershed is the collection of retrofit strategies of the appropriate analysis areas. These strategies can be summarized in a single report and summarized in tables of actions necessary to retrofit an analysis area. See Table 2.8 (page 99) for an example of the strategy, actions, relative costs, and implementation sources for Deep Creek. Assign Order of Implementation A second component of The Urban Retrofit Plan is a schedule of implementation. The easiest schedule would be implementation by analysis area by order of ranking in Table 2.6. In our example, Deep Creek analysis area has the highest rank. Its strategy should be implemented first. Remember that some management practices prescribed for Deep Creek can also be applied to the entire watershed. If this is true and the implementation cost is low, then the practices applicable in large areas should be implemented as a high priority. Source controls often meet these conditions. This analysis assumes that the Magothy River is the highest priority watershed for retrofitting. Other watersheds in Anne Arundel can also be analyzed using these methods. The collection of the individual urban retrofit plans would be the comprehensive plan for the County. Implement the Urban Retrofit Plan To implement the Plan, four actions are required. 97 1. Detailed site investigations should be performed and any necessary engineering designs be drawn. For example: Deep Crook shows promising sites for infiltration and a wet pond. These areas would be inspected and have plans developed. 2. The suggested source controls under public management must be inspected more closely for legal and administrative feasibility. 3. Costs of implementation would be estimated for all feasible control measures in each analysis area strategy. Based on the estimated costs and type of control, funding sources will be selected. Id. Finally Anne Arundel County would implement The Magothy River Urban Stormwater Retrofit Plan by acting on the strategies in the Plan. The same series of actions are also implemented for other priority watersheds in the County in order of rank. A 'A A 98 Table 2.9 Deep Creek Urban Retrofit Strategy. Category Management Practice Location(s) Action Required Estimated Funding Cost Source Existing Management Source Control Solid waste management All Deep Creek Evaluation of mgmt. Low/Low 1 & public education. Roadway de-icing All roads subject Evaluation of policy. Low/Low 1 to de-icing & change for sensitive areas. Erosion Control Publically-owned lands Need site surveys Install where necessary. Low/Low-Mod. 1,2,3,7 Runoff Control Detention basin See Figure 2.13 Site survey & design for Low/Low 2,3,5,6 retrofit. Four small wet ponds See Figure 2.9 Site survey & evaluation Low/Low-Mod. 2,3,5,6,7 of feasibility. Residential roof & lot All Deep Creek Site identification Low/Low 1,2,7 drainage public education. New Management Source Control Street & parking lot Higher density resid. I-Site identification & Low/Low-Mod. 1,2,7 sweeping & commercial areas public education. II-Ordinance. Low/Low-Mod. 1,2,7 Public fertilizer All Deep Creek I-Public education Low/Low 1,2,6,7 pesticide control II-Ordinance Low/Low-Mod. 1,2,6,7 Pet waste management All Deep Creek - focus I-Education Low/Low 1,2,6,7 on higher density II-Ordinance Low/Low-Mod. 1,2,6,7 residential areas. Marina materials & chemicals handling See Figure 2.9 Public education Low/Low 1,2,6,7 Erosion Control Drainageways & stream Potentially all areas Site surveys & install. Low/Mod.-Hiqh 1,2,3,4,5,7 valleys (see Figure 2.9) Runoff Controls Potential wet pond See Figure 2.13 Site survey & design. Low/ High 1,2,3,4,5,6 Area for teporary See Figure 2.13 Site survey & design. Low/Mod.-High 1,2,3,4,5,6 runoff storage Stormwater inlets Storm drain system maps Site survey & designs. Low/Mod.-High 1,2,3,5,6 or detailed site survey. Urban forestry All Deep Creek Public education & install Low/Low 1,2,3,5,7 on public lands. Drainage pathways on Storm drain system maps Site survey, design, & Low/Low-Mod. 1,2,3,4,5 public lands or detailed site survey. install. Funding Source: I - Operating Budget. 3 - Critical Area Mitigation Fees. 5 - Chesapeake Bay Initiatives. 7 - Private. 2 - SWM Utility Fees. 4 - State or Local Special Bonds. 6 - Federal Clean Water Act. 99 i,g Appendices I I I I APPEMIX A I Segments in the Baltimore Region I I I 'A A A A A-1 Maryland Major Water Drainage Area Classification System Basin Sub-Basin Segment 02 12-02 Lower Susquehanna R. 01 L. Susquehanna R. Area 02 Deer Creek 03 Octoraro Creek 04 Conowingo Dam Area 02 13-07 Bush River 01 Bush River 02 Lower Winters Run 03 Atkisson Reservoir 04 Bynum Run 05 Aberdeen Proving Grd. 06 Swan Creek 02 13-08 Gunpowder River 01 Gunpowder River 02 Lower Gunpowder Falls 03 Bird River 04 Little Gunpowder Falls 05 Loch Raven Reservoir 06 Prettyboy Reservoir 07 Middle Rvr./Browns Cr. 02 13-09 Patapsco River 01 Back River 02 Bodkin Creek 03 Baltimore Harbor 04 Jones Falls 05 Gwynns Falls 06 Patapsco Rvr.-Mainstem & Lower North Branch 07 Liberty Reservoir 08 Patapsco Rvr.-South Branch 02 13-10 West Chesapeake 01 Magothy River 02 Severn River 03 South River 04 West River 05 Other Drainages A-2 Maryland Major Water Drainage Area Classification System Basin Sub-Basin Segment 02 13-11 Patuxent River 01 Patuxent Rvr. Mainstem -Mouth to Ferry Lndg. 02 Patuxent Rvr. Mainstem -Ferry Lndg. to Rt.214 03 Western Branch 04 Patuxent Rvr. Mainstem -Rt.214 to Rocky Gorge Dam 05 Little Patuxent Rvr. 06 Middle Patuxent Rvr. 07 Rocky Gorge Dam Area Drainage 08 Patuxent Rvr.-Brighton Dam to headwaters 02 14-03 Middle Potomac River 01 Potomac Rvr.- Shenandoah Rvr. to Monocacy Rvr. 02 Lower Momocacy Rvr. 03 Upper Momocacy Rvr. 04 Double Pipe Creek 05 Catoctin Creek Source: Maryland office of Environmental Programs. Baltimore. April 15, 1986. A-3 APPENDIX B Water Quality Evaluation Values Legend (E) - Excellent water quality (0) - Good water quality M - Fair water quality (P) - Poor water quality meets f1sWe/swimmable criteria does not meet fldiable/swimmable criteria Comparison of sub-basin and segment water quality evaluations from 1982, 1984 and 1986 Maryland 305(b) reports Code Sub-basin/ Segment 1982 1984 1986 Comments 21301 Ocean/Coastal G G -01 Atlantic Bay E E -02 Assawoman Bay G G -03 Isle of Wight Bay + P/G -04 Sinepuxent Bay + G -05 Newport Bay G G/E -06 Chincoteague Bay E E 21302 Pocomoke River G G -01 Pocomoke Sound + G -02 Lower Pocomoke River + F -03 Upper Pocomoke River + F -04 Dividing Creek + F -05 Nassawango Creek + F -06 Tangier Sound E E -07 Big Annemessex River + G -08 Manokin River F/G 21303 Nanticoke/Wicomico River G G -01 Lower Wicomico River + F/G -02 Monie Bay + G -03 Wicomico Creek + G -04 Wicomico River Headwaters + F -05 Nanticoke River + G -06 Marshyhope Creek + G -07 Fishing Bay E E -08 Transquaking River + G 21304 Choptank River G G -01 Honga River E E -02 Little Choptank River G G -03 Lower Choptank River + G -04 Upper Choptank River + G -05 Tuckahoe Creek + G 21305 Chester River G F/G -01 Eastern Bay + G -02 Miles River + G -03 Wye River + F/G -04 Kent Narrows/Prospect Bay + F/G -05 Lower Chester River + G -06 Langford Creek + G -07 Corsica River + F/G -08 Southeast Creek + F -09 Middle Chester River + F -10 Upper Chester River + F -11 Kent Island + G B-2 Code Sub-basin / Segment 1982 1984 1986 Comments 21306 Elk River 0 0 -01 Lower Elk River 0 0 -02 Bohemia River + 0 -03 Upper Elk River + F F -04 Back Creek + 0 -05 Little Elk River + F -06 Big Elk Creek + F -07 Christine River + F -08 Northeast River + 0 -09 Furnace Bay + 0 -10 Sassafras River + 0 -11 Still Pond/Fairlee + 0 20503 Conewago Creek new basin -01 Conewage Creek 21202 Lower Susquehanna River + -01 Lower Susquehanna River + 0 -02 Deer Creek + 0 -03 Octoraro Creek 0 -04 Conowingo Dam/Susquehanna Run + 0 -05 Broad Creek + 0 21307 Bush River G O -01 Bush River + F -02 Lower Winters Run + 0 -03 Atkisson Reservoir + 0 -04 Bynum Run + 0 -05 Aberdeen Proving Ground + 0 -06 Swan Creek + F 21308 Gunpowder River O F/G -01 Gunpowder River + F -02 Lower Gunpowder Falls + 0 -03 Bird River + F -04 Little Gunpowder Falls + 0 -05 Loch Raven Reservoir + F/0 -06 Prettyboy Reservoir + 0 -07 Middle River/Browns Creek + 0 B-3 Code Sub-basin / Segment 1982 1984 1986 Comments 21309 Peteosco River F P/G -01 Back River + P -02 Bodkin Creek + F -03 Baltimore Harbor - P/F -04 Jones Falls +/- P/O -05 Gywnns Falls +/- P/0 -06 Patapsco - Lower North Branch + F/0 -07 Liberty Reservoir + 0 -08 South Branch Patapsco + 0 21310 West Chesapeake + F -01 Magothy River + F -02 Severn River + F -03 South River + F -04 West River + F -05 West Chesapeake Bay Area + 0 21311 Patuxent River + F -01 Patuxent - Mouth to Ferry Ldg + 0 -02 Patuxent - Ferry Ldg to Rt 214 + F -03 Patuxent - Western Branch + F -04 Patuxent - Rt 214 to Rocky F F -05 Little Patuxent + F -06 Middle Patuxent + O -07 Rocky Gorge Dam Area + 0 08 Patuxent - Brighton Dam E 0/E 21399 Chesapeake Bay F/O F/O -96 Upper Chesapeake Bay + F -97 Middle Chesapeake Bay + F -98 Lower Chesapeake Bay + 0 21401 Lower Potomac River G/E -01 Potomac - Smith Pt to Mouth G/E G/E -02 Potomac - Marshall Hall to Smith Pt 0 F/O algal blooms -03 St. Marys River 0 0 -04 Breton BaV O/E O/E -05 St. Clements Bay O 0 -06 Wimcomico River 0 0 -07 Gilbert Swamp 0 0 -08 Zekiah Swamp 0 0 -09 Part Tobacco River 0 F algal blooms -10 Nanjemoy Creek 0 0 -11 Mattwoman Creek 0 F/0 B-4 Code Sub-basin/ Segment 1982 1984 1986 Comments 21402 Potomac River - Washington Metro F/G F/G -01 Potomac - Chain Br to Marshall Hall G/P F -02 Potomac - Monocacy to Chain Br 0 0 -03 Piscataway Creek 0 F algal blooms -04 Oxon Run 0 F -05 Anacostia River F F/0 -06 Rock Creek F/P F/0 82 report included DC -07 Cabin John Creek F/0 F/0 -08 Seneca Creek F/0 0 21403 Middle Potomac O F/G -01 Potomac - Shenandoah to Monocacy F O error In 82 report -02 Lower Monocacy F/0 F/0 -03 Upper Monocacy F/0 F/0 -04 Double Pipe Creek 0 F/0 -05 Catoctin Creek 0 0 21405 Upper Potomac River O/E O -01 Potomac - Hancock to South Branch 0 0 -02 Antietam Creek 0 F/0 Hagerstown Impact -03 Marsh Run F 0 -04 Conococheague Creek 0 0 -05 Little Conococheague Creek 0 0 -06 Licking Creek 0 0 -07 Tonoloway Creek 0 0 -08 Allegany County Drainage 0 0 -09 Little Tonoloway Creek 0 0 -10 Sideling Hill Creek E G/E -11 Fifteen Mile Creek 0 0 -12 Town Creek 0 0 21410 North Branch Potomac F F -01 Lower North Branch F F/0 Bloomington Reservoir -02 Evitts Creek 0 0 -03 Wills Creek 0 P/0 acid mine drainage -04 Georges Creek P P -05 Upper North Branch P P -06 Savage River O/E O/E 50202 Youghlogheny River O P/0 -01 Youghiogheny River 0 F/0 swimming ban -02 Little Youghiogheny River 0 P/0 swimming ban -03 Deep Creek Lake 0 0 -04 Casselman River 0 F swimming ban Source: Maryland Office of Environmental Programs. Baltimore. April 15, 1986. B-5 I I I I APPPENDIX C I Maryland Watershed Priority List I i I I I I I I I I I I I m C-1 1986 Maryland Watershed Priority List Miles Code Sub-basin Imea2t!j @f!@qt 2f 1!2@ct Loch Raven Reservoir 02-13-08-05 Gunpowder River 26 Algal blooms (primary water supply) Back River 02-13-09-01 Patapsco River 3 Algal blooms, fish kills Upper Chesapeake Bay 02-13-99-96 Chesapeake Bay 23 Algal blooms, fish kills, Lower Susquehanna River 02-12-02-01 Susquehanna River 2 swimming ban Middle Chesapeake Bay 02-13-99-97 Chesapeake Bay 24 Algal blooms Lower Chesapeake Say 02-13-99-98 Chesapeake Bay 71 Algal blooms, low oxygen Patuxent River - Mouth to Ferry Ldg 02-13-11-01 Patuxent River 2 Swimming ban, shellfish - Ferry Ldg to Rt 214 02-13-11-02 11 ban, aquatic life - Rt 214 to Rocky Gorge 02-13-11-04 24 stressed - Western Branch 02-13-11-03 16 Little Patuxent River 02-13-11-05 35 Potomac - Smith Point to Marshall Hall 02-14-01-02 Lower Potomac River 24 Algal blooms, aquatic - Marshall Hall to Chain Br. 02-14-02-01 Washington Metro Area 34 life stressed Baltimore Harbor 02-13-09-03 Patapsco River 7 Swimming ban, fish kills, Bodkin Creek 02-13-09-02 5 aquatic life stressed Jones Falls 02-13-09-04 9 Gwynns Falls 02-13-09-05 12 Isle of Wight Bay 02-13-01-03 Ocean/Coastal 6 Shellfish closures, aquatic life stressed Lower Monocacy River 02-14-03-02 Middle Potomac 24 Aquatic life stressed Upper Monocacy River 02-14-03-03 34 Double Pipe Creek 02-14-03-04 30 Liberty Reservoir 02-13-09-07 Patapsco River 17 Algal blooms (primary water supply) C-2 1986-Maryland Watershed Priority List - Continued Mi les �e9ment Code Sub-basin Impmn! Eff!qt 2! !TPIct 12 Magothy River 02-13-10-01 West Chesapeake 11 Shellfish closures, Severn River 02-13-10-02 16 algal blooms, fish South River 02-13-10-03 16 kills 13 Lower Choptank River 02-13'-04-03 Choptank River 10 Shellfish closures, algal blooms 14 Wicomico River headwaters 02-13-03-04 Nanticoke/Wicomico River 10 Swimming ban, algal blooms 15 Prettyboy Reservoir 02-13-08-06 Gunpowder River 13 Algal blooms (secondary water supply) 16 Upper North Branch Potomac 02-14-10-05 North Branch Potomac 27 Aquatic life stressed Georges Crook 02-14-10-04 17 17 Youghiogheny River 05-02-02-01 Youghioghony'River 1 Swimming ban, aquatic life Little Youghiogheny River 05-02-02-02 2 stressed 18 Kattawooan Crook 02-14-01-11 Low Potomac River 10 Algal blooms, aquatic Piscataway Crook 02-14-02-03 Washington Metro Area 5 life stressed 19 Miles River 02-13-05-02 Chester River 8 Shellfish closure Wye River 02-13-05-03 7 20 Lower North Branch Potomac 02-14-10-01 North Branch Potomac 52 Aquatic life stressed Wills Crook 02-14-10-03 14 21 Casseloan River 05-02-02-04 Youghiogheny River 12 Swimming ban, aquatic lift stressed 22 Anacostia River 02-14-02-05 Washington Metro Area 5 Aquatic life stressed Source: Maryland office of Environmental Programs. Baltinfore. April 15, 1986. c-3 APPENDIX D Using Natural Soil Groups to Assess Existing Urban Areas The following material has been excerpted from the Maryland Department of State Planning publication: Natural Soil Groups of Maryland, Technical Report, Dece;-bei@ 1-973. The enclosed information includes: 1. "Natural Soil Group Identification Symbols", pg. 20. 2. "How to Use a Natural Soil Group Map", pg. 57. 3. Table 1. "Estimated Physical and Chemical Properties", pgs. 61 and 62. 4. "Engineering Uses of Soils", explanation of Table 1, pgs. 58-60. 5. Appendix A - Listing of Natural Soil Group Map Symbols by County. a. Anne Arundel County pgs. 77-80 b. Baltimore County 81-85 c. Carroll County 90-92 d. Harford County 108-110 e. Howard County 111-113 D-1 DESCRIPTION OF NATURAL SOIL GROUPS IN MARYLAND NATURAL SOIL GROUP INDENTIFICATION SYMBOLS Each soil group is designated on the Natural Soil Group Map by a capital letter and a number, such as B1. If a group contains soils that have a wide range in slope, then the group is subdivided into slope ranges indicated by the addition of a lower case letter (see Figure 6). A lower case letter a means that slopes range from 0 to 8 or 10 percent; b, 8 to 15 or 10 to 15 percent; and c, steeper than 15 percent. On the Eastern Shore, practically all soils mapped have slopes of less than 10 percent; therefore, to reduce map clutter, only the capital letter and number are designated for soils on the Eastern Shore. For example, 131 on the Eastern Shore and Bla in the Piedmont region both indicate soils in Group 131 with slopes of 0 to 10 percent. The Natural Soil Group symbols are not connotative, although the lower-case letters a, b, and c indicate specific slope ranges. In general, the Natural Soil Groups are arranged in order of increasing limitations or problems for most uses. Drainage class or wetness is one of the prime considerations in land use. Thus, the system is connotative in that the soils, in general, get progressively wetter moving from A to G in the alphabet. Also, in general, the number -designation indicates the intensity of an unfavorable feature such as wetness, droughtiness, or very high or low permeability. For example, the soils in Group A are'sandy and droughty, but Al is not so droughty as A2. The' soils in Groups 131, 132, and B3 are all deep and well drained, but have progressively slower permeability. Thus, the numbers indicate increasing limitations within the - capital letter designation. In most groups, the numbers represent increasing limitations of permeability. Natural soil group boundary Detailed soil survey IVIKB2 mapping unit boundary Detailed soil surve 9013 mapping unit sym SaI32 MkA la Slope (0-10%) Slight permeability limitation Deep, weildrained soils that are moderately or moderately rapidly permeable FIGURE 6 20 HOW TO USE A NATURAL SOIL GROUP MAP I .Locate the area of interest on the Natural Soil Group Map. 2. Observe the Natural Soil Group symbol or symbols consisting of a capital letter, a number, and a lower case letter. (See "Natural Soil Group Identification Symbols" for a detailed explanation of the natural soil group symbolization.) 3. Refer to "Description of Natural Soils Groups" in the table of contents. Move to the section on "Discussion of Each Natural Soil Groupings." Locate the appropriate description. They are listed in alphabetical order, from Al to H2. 4. Read the introductory paragraphs. Specific interpretations are made for each Natural Soil Group under the headings for Unique Value, Cropland, Urban, Recreation, Wildlife and Woodland. These interpretive statements may apply to more than one specific natural soil group if slope does not have an important effect. For example, specific groups 132a and B2b are interpreted together for recreation in broad group 82. Note: It is important that users read the two or three introductory paragraphs of each natural soil group description. These paragraphs describe the important soil characteristics and features that would affect most uses. They are important supplements to the specific use interpretations under the various headings. 5. For specific use interpretations not noted in the descriptions, turn to the interpretive tables further in this text. From the information in these tables, color soil interpretation maps can be prepared by coloring any area rated slightly limited or good with green; moderately limited or fair with yellow; and severely limited or poor with red. This system is analogous to the traffic light system where green indicates no special hazards; yellow a caution color; and red a full stop or a serious hazard. Ratings of slight, moderate, and severe indicate the relative degree of problems to be overcome to make an area suitable for a specific use. 6. Keep in mind that Natural Soil Groups were devised for broad land use planning, not for detailed interpretations of specific acres or lots. If a rather specific interpretation for a small area is needed, spot this area on the map and read the detailed soil map symbol with a magnifying glass, if the natural soil group map has a detailed soil map base. Locate this detailed map symbol in the Guide to Mapping Units in the appropriate published soil survey report, determine the soil name, and trace out the detailed descriptions and interpretations. If the natural soil group map is not on a detailed soil map base, specifically identify the area on interim sets of detailed maps available for reference at the county field office of the Soil Conservation Service and refer to manuscript copies of the detailed soil descriptions and interpretations. On-site detailed investigations are needed for specific sites. Note: The primary value of soil surveys is to provide resource information for planning prediction, not absolute land use descriptions for specific acres or lots. S7 TABLE 1. ESTIMATED PHYSICAL AND CHEMICAL PROPERTIES Depth to clas%-ficm-nn Runoff Sip"olde, Natural Soil Seasonal Depth E,od,h,hly potential .... lial'o. A-lable Sh-1, I G, h (K factor) (Hydroloqic maximum Permeability Perco,ai,orv water Reaction Se.11 ouls h.9 @fio- Dn-ani tf-f-f AASHO q,clpl Z I. C:I... "pacliv prilrnt..0 .;.I Bedrock write utlace USDA -e@turps M % table (inches) Ifeell finches) fin /h, I (in /h,,j I- '-A I in lin. fpH) of Sniff -Nwl Ala, Alh. Alc 774 4- 060 Loamy sand. sm. SP A 2. A 3. Very low Low > 6.0 Fastpr than 02 06 4.0-5.0 Low Low sand or sandy A 4 1.171 IAI 45 In- A2 724 1 10 060 S."d SP or A 3 Very low Low N/A >60 Faster than < O@06 5@0 8.0 Low Low So SM I III (A) 45 Bill, 81b. Sic 72- 3- 060 Sit. loam. IVIL. CL. A 4. A-6. M.de,all, Mod-It, 040.6 0.60-20 4560 .12 24 4.5-65 Low to mod"'a". lo.m. fine sm, Sc. A 7. A., 1 321 IV 1,,w Mod-(t, sandy loam. Cit. MH IRI sandy loam. siltV clay loam, clay loam. &.fly clay. clay 82a, 132b. 82c 72- 4- 060 Silt loam, loam. IVIL. CL, A 4, A 6, V@,y high Moderate 030.4 0.20-060 Slower than .12 .74 41@5 7 3 Low to Mode,.,,- qravp.lly loam, GM A 7, A 2 1 431 ly h,qh 60 Mod-ii, clay Inam. IC) silty clay 103- 83 72- 5. 0-0 Clay. silty CH, CL. A-7, A-6. High Moderate 03 <0,60 Sic., then .06 .24 4.0-5,0 Low to Mode'a,", clay. sill loam. ML, SM A 4. A 2 1 3 71 IV high 60 Moderate to m. loamy (C) Cla, C Ih. C Ic 2040 In bed. 0.40 Silt loam, loam. ML, CL A 4. A 6. Low Moderate. 01 0,6060 Faster than .12 .24 4.07.3 L ow Moderate rock shalv Silt loam. GM. SM A 2 1.22) ly fl@qh 60 shilV loam. channe,V loam. channefy sill Inam. sandy loarn C2 2040 34 OL40 Silly clay loam, CH, CL A-7, A-6 H.qh Moderate- 0.3 <0.60 Slower than .12-20 5.0-75 Moderaip Moder.t, silty clay, clay 1.3 71 ly high 60 1. High (C) DIa. Dlh. Dic Les, than In bad. 020 Shaly silt loam. GM. GC. A 2, A-4. Low Mode'al. 03 060-6.0 Slower than .18 24 4.073 Low to Mode'll" 20 rock shaly loam. clay. ML, CL, A-6. A .7 1 28) ly high to 60 to faster Moderate silly clay loam, high (C or than 45 silty clay D) El 12- 0.60 Sandy loam, sm, Sc. A 2, A 4. Low Moderate. 0.4-0.6 0606.0 Faster than .12 @24 4.05.0 Low H.iih sandy clay Sp A 3 (@28) IV high 60 loam, loamy (C) Sand. sand E2a, E2b 72, 1.3 0-60 Sill loam. ML, CL, A-4, A 6. Very high Moderate- 0.30.4 < 0.60 Slower than .12-.24 4.0-6.5 Low to High loam. silly sm. SIC A. 7. A 2 1.43) IV hiqh 60 K,de,al, clay loam, 1c) I me Sandy loom, sandy clay loarn E3 77, 1 1/1.2% 0-60 Silt loam. ML. CL, A 4. A-6, High Moderate- 0.4 0,20-0.60 Slower than Ag-,24 4.5-5.5 Low to High loam. silly sm A-2 (.37) IV high 60 Moderate clay foann IC) F 1 72- 00 (160 Loamy sand, sm SP A 2. A-3 N/A High 1.0 >6.0 Faster than <0.06 3.5-5.0 Low High Sand (D) 45 TABLE 1. ESTIMATED PHYSICAL AND CHEMICAL PROPERTIES JCONT'D.) Depth to Classification Sprinkler Runoff Natural sort Seasonal Depth E,cid.bfity pot-tual irrigation Ati,ailable Shrink- F'o'l 1K factor) IHydrologic ma. Im.m Permeability Percolation ale, Reaction swat I acl.- G, o.ps Bedrock high from Dominant Unified AASHO group) application capacity potential potential wet a, surface USDA textures ales ,.so (inches) (feet) (inches) 1,..Ih,.) Imin./in.) fin./in. (pH of soil) value) F2 72+ &1 O@60 Sandy loam. SM. M L, A-2. A-4. Low High 0.4-0.6 0,60-2.0 Faster than .12-.24 4.0-5.0 Low High fine sandy Sc. SP A-3 1.28) (0) 60 loam. sandy clay loam. loam, loamy sand F3 72+ &1 0-60 Silly clay CL. CH, A-6. A-7. Very high High 0.3 <0.60 Slower than iB-.24 4.0-7.8 Moderate High loam, clay ML, SC, A-4, A+2 J.431 (D) 60 to High loam. silty SM, MH clay, clay. loam, sift loam GI 72* 3- 0,60 Sift loam. ML. CL. A 4, A 6, N/A Mod'!. at. 0 5 0.7 0,20-2.0 Faster than .12.24 4,0-1.3 Low it) Mod. to loam, fine MH' SM, A-5, A-2, ly 10. to 45 to Slower Moderate High sandy loam, SP A 3 Mod, high than 60 sandy loam, (B or C) silty clay loam G2 72- 011 &60 Sift loam, ML. CL, A-4. A -6. NIA H.,Ih 05 0,60-6.0 Faster than .18-.24 4,0-7.3 Low to High filly clay SM. OL. A 2, A-5 (D) 45 to Slower High Inam, silty pt than 60 clay. fine sandy loam, sandy loam, loam. muck G3 72+ 0 0-60 Variable Variable Variable N/A NIA N/A Variable V-able Variable 3.5-9.0 Low to Variable High Hla. H 1b. H1c Too variable to rate. Determine the specific soil series name from the detailed soil map and.use the information for the group that se'.es's in. H2a. H2b. H2c Too variable to rate. Determinte the specific soil series name from the detailed soil map and use the information for the group that series is in. ENGINEERING USES OF SOILS TABLE 1 Table 1, "Estimated Physical and Chemical Properties," lists soil properties relevant to the engineering uses of soils. The properties are given for each Natural Soil Group; therefore, a wide range of properties is covered. The primary purpose of the table is to provide some properties of soils that will help users select large areas that have potential for the use they have in mind, and to help them quickly eliminate some others that obviously do not have the desired properties and features. Table 1 does not eliminate the need to use detailed soil maps and soil survey reports for any Natural Soil Group area, nor does it eliminate the need for further investigation at sites selected for specific engineering works, especially works that involve heavy loads or that require excavations to depths greater than those shown in Table 1. Also, inspection of sites, especially small ones, is needed because the Natural Soil Group delineations contain some inclusions of other soil delineations that have properties and features different from the Natural Soil Group in which they occur. Even the detailed soil map delineations may have inclusions of other kinds of soil that have strongly contrasting properties and different suitabilities or limitations for soil engineering. The following paragraphs explain the meaning and purpose of each individual column in Table 1, "Estimated Physical and Chemical Properties." Natural Soil Groups - All of the Natural Soil Groups are listed in this col umn Slope has little effect on the physical and chemical prope-rties of soils. Therefore, some-groups. that, are aii e except tot slope are grouped together in t,h-is tahl.e.. Depth to Bedrock - This is the distance from the surface of the soil downward to the surface of the rock layers. For the Natural Soil Groups that occur in the Coastal Plain (All and A2), depth to bedrock is shown as 72 + inches. Actually, over most of the Coastal Plain depth to bedrock is many hun- dreds of feet, but, in mapping, the soils were observed only to a depth of 6 feet. Therefore, depth greater. than 72 inches is assumed but not specified. Depth to Seasonal 'High Water Table - This is the distance from the surface of the soil downward to the highest level reached in most years by ground water. It is the highest part of the soil or underlying rock material that is wholly saturated with water. Most of he soils in Natural Soil Groups E2a and E2b have a perched water table above a fragipan or clayey layer which may be separated from a lower water table by a dry zone many feet thick; thus, the water table referred to in this column may or may not be continuous with a water table from which water is drawn for use in the home. If the water table is in bedrock, rather than in the soil, it is so indicated. Depth from Surface - Unless the soil is located less than 60 inches above bedrock, the depth from surface is expressed as 0-60 inches. This does not imply that the soils are only 60 inches deep, but rather that the estimates in the accompanying columns are for the 0-60 inch depth and not below. Dominant U.S.D.A. Textures - These are expressed in standard terms used by the U.S. Department of Agriculture. These terms take into account relative percentages of sand, silt and clay in a soil sample that is less than 2 millimeters in diameters. If the soil contains gravel or other particles coarser than sand, an appropriate modifier is added, as for example, "gravelly" loam or "shaly" loam. Percentages of material passing various sieve sizes are not estimated in Table'll because of the many different soils comprising each Natural Soil Group; however, sieve data for specific soil series are available in published soil survey reports for detailed soil maps. Textures described are those that may be encountered within the 0-60 inch depth of the soils in a Natural Soil Group. Textures are listed in order of dominance for the group. In general, the heaviest (most clayey) textures ordinarily occur in the subsoil at depths of 1 to 4 feet and are less clayey above and below these depths. Unified Classification - In the Unified system, soils are classified according to particle-size distribution, plasticity, liquid limit and organic matter. Soils are grouped in 15 classes. There are eight classes of coarse grained soils, identified as GW, GP, GM, GC, SW, SP, SM, and SC; six classes of fine- grained soils, identified as ML, CL, OL, MH, CH, and OH; and one class of highly organic soils, identified as PT. Soils on the borderline between two classes are designated by symbols for both classes, for example SP-SM. A A S8 In this column, Unified classifications are grouped for the entire 0-60 inch depth. Where CL and CH classes are shown, they can be expected to occur between depths of 1 and 4 feet, or in what is com- monly called the "subsoil". Unified classes are listed in order of dominance within the group. AASHO Classification - This system is used to classify soils according to those properties that affect use in highway construction and maintenance. A soil is placed in one of seven basic groups based on grain-size distribution, liquid limit and plasticity index. In group A-1 are gravelly soils of high bearing strength, the best soils for subgrade (foundation). At the other extreme, in group A-7, are clay soils that have low strength when wet and that are the poorest mineral soils for subgrade, In this column in Table 1, where classes A-6 or A-7 occur, they are generally in the subsoil, or at depths between 1 and 4 feet. AASHO classifications are listed in this column in order of dominance for the Natural Soil Group. Erodibility (K factors) - This is a measure of the susceptibility of bare surface soil to erosion. The K-factor is a component of an established formula for estimating potential erosion from a field or watershed by the "soil loss formula", which also considers vegetation, climate, slope, and other factors. a4AiKLO@@@@only. They are not suitable for estimating erosion from development sites where the subsoils or substrata K-ave been exposed by grading. The subsoils and sub- strata have different erodibility (K factors). Runoff potential (Hydrologic Group) - The qualitative rating is given along with the Hydrologic Group symbol, in parenthesis. When fully saturated, soils in Hydrologic Group A have the lowest runoff potential and those in Group D the highest. Hydrologic soil group descriptions are used in watershed planning to estimate runoff from rainfall. To determine the groups, soil properties are con- sidered that influence the minimum rate of infiltration obtained for a bare soil after prolonged wetting. The influence of vegetative cover, conservation practices, and topography is not treated in hydrologic soil groups. The following are definitions of the four hydrologic groups: A. (Low runoff potential). Soils having high infiltration rates even when thoroughly wetted. These con- sist chiefly of deep, well to excessively drained sands or gravels. These soils have a high iate of water transmission in that water readily passes through them. B. (Moderately low runoff potential). Soils having moderate infiltration rates when thoroughly wetted. These consist chiefly of deep, moderately well to well drairied soils with moderately fine to moderately coarse textures, These soils have a moderate rate of water transmission. C. (Moderately high runoff potential). Soi 'Is having slow infiltration rates when thoroughly wetted. These consist chiefly of soils with a layer that impedes downward movement of water, soils with moderately fine to fine texture, or soils with moderately high water tables. These soils may be somewhat poorly drained. They have a slow rate of water transmission. D. (High runoff potential). Soils having very slow infiltration rates wben thoroughly wetted. These consist chiefly of clay soils with a high swelling potential, soils with a permanent high water table, soils with a claypan or clay layer at or near the surface, and shallow soils over nearly impervious material. These soils have a very slow rate of water transmission. Sprinkler Irrigation Maximum Application Rates - This column shows the maximum rate in'inches per hour that irrigation water can be applied to the soils in each group. Although these rates were established for application of ground or stream water by sprinkler on cropland, they can also be used as guides for applying waste water to land. A rapid application rate, such as 1.0 inch per hour for Group Ala, Alb, and Alc, simply means that the surface soil has the capability to absorb irrigation or waste water applied at that rate. For the overall ratings of Natural Soil Groups as sites for disposal of waste water, see Table 2. Permeability - This is the quality of a soil that enables it to transmit water or air, expressed in inches per hour. Accepted as a measure of this quality is the rate at which soil transmits water while saturated. That rate is the "saturated hydraulic conductivity" of soil physics. The estimates shown are for downward movement only and not lateral movements, such as along the surfaces of fragipan, plow pans and surface crusts. Permeability rates shown are based on the least permeable section of the soil, which is generally the "subsoil" or that section of soil between depths of 1 and 4 feet. 59 The permeability classes and corresponding numerical ranges are shown below: Permeability class Numerical range (inches per hr.) Very slow Less than 0.06 Slow 0.06-0.20 Moderately slow 0.20-0.60 Moderate 0.60-2.0 Moderately rapid 2.0-6.0 Rapid or very rapid greater than 6.0 Percolation - This is the rate, in minutes per inch, at which water can move through a soil with moisture at field capacity. Classes of permeability can be rated to classes of percolation although the correlation is not perfect, Permeability rates shown in Table 1 were measured as a hydraulic conductively rate by the Uhland core method, while the corresponding estimated percolation rates were measured by the Auger hole method. Estimated percolation rates shown in Table 1 are for the depths at which tile lines for shallow sub-surf ace septic tank absorption fields are generally placed and not for substrata in which deep, dry wells are placed. The following are the permeability-percolation relationships used in Table 1. Each correspon- ding class is not a mathematical reciprocal of the other because the method of measuring each is different. Permeability Percolation in./hr. min./in, More than 1.0 Faster than 45 1.0-0.6 45-60 Less than 0.6 Slower than 60 Available Water Capacity - This is the ability of soils to hold water for use by most plants. It is commonly defined as the difference between the amount of water in the soil at field capacity and the amount in the soil at the wilting point of most crop plants. The ranges shown in Table 1 for each Natural Soil Group cover the range in texture for each of the groups. Reaction - This is the degree of acidity or alkalinity of a soil group, expressed in pH values. In Table 1 the values shown are the estimated ranges necessary to cover all of the soils within a group. Since soil reaction was not one of the major soil characteristics used for establishing the Natural Soil Groups, the range in values for some groups in Table 1 is wide. The following are the numerical ranges for each of the reaction classes: Class pH Extremely acid 4.5 Very strongly acid 4.5-5.0 Strongly acid 5.1 -5.5 Medium acid 5.6-6.0 Slightly acid 6.1-6.5 Neutral 6.6-.7.3 Mildly alkaline 7.4-7.8 Moderately alkaline 7.9-8.4 Strongly alkaline 8.5-9.0 Very strongly alkaline 9.0 Shrink-swell potential - This is the quality of the soil that determines its volume change with changes in moisture content. It is inf I benced by the amount of moisture change and the amount and kind of clay in the soil. Building foundations, roads, and other structures may be severely damaged by shrinking and swelling of soil. The three classes of shrink-swell used in Table 1 can be related to a quantitative method of measuring shrink-swell, known as "the coefficient of linear extensibility" (COLE), as follows: Classes COLE Low 0.03 Moderate .03-.06 High 0.06 Frost-action Potential - The action pertains to not only the heaving of soil as freezing progresses but also to the excessive wetting and loss of strength during thaw. Both the textures of soils and their potential for forming expansion ice lenses from a sustained source of water were considered in determining the frost-action potential. 60 ANNE ARUNDEL COUNTY i 0 0 a IL ts III 14L MAP 49 z SYMBOL MAPPING UNIT zoo AdA Adelphia sandy loam, 0 to 2 percent slopes ---------------------- Jjv-5 580 Li AdB Adelphia sandy loam, 2 to 5 percent slopes ---------------------- IIG-36 1670 El AsA Adelphia silt loam, 0 to 2 percent slopes ----------------------- I1w-1 220 Bi AsB Adelphia silt loam, 2 to 5 percent slopes ----------------------- lIe-16 250 El BeB2 Beltsville silt loam, 2 to 5 percent slopes, moderately eroded-- IIe-13 430 92a 618 Beltsville-Urban land comFlex, 0 to I percent slopes ------------ ------ 430 E24L Bm Bibb silt loam --------------------------------------------------- IIIW-7 11,000 G2 BuA Butlertown silt loam, 0 to 2 percent slopes --------------------- 1Iw-1 L90 B2& BuB2 Butlertown silt loam, 2 to 5 percent slopes, moderately eroded-- IIS-16 2,200 B2& BuC2 ButleTtown silt loam, 5 to 10 percent-slopes, moderately eroded -------------------------------------------------------- 1110-16 260 B2& BuC3 Butlertown silt loam, 5 to 10 percent slopes, severely eroded --- IVe-9 350 B2& BuD3 Butlertown silt loam, 10 to 15 percent slopes, severely eroded-- VIe-2 230 B2b CaB2 Chillum silt loam, 2 to 6 percent slopes, moderately eroded ----- IIS-7 320 B2a CaC2 Chillum silt loam, 6 to 12 percent slopes, moderately eroded ---- I-LIe-7 330 32& CbB Chillum-Urban land complex, 0 to 6 percent slopes --------------- 3?0 B2a CcB2 Christiana silt loam, 2 to 5 percent slopes, moderately eroded-- lie-42 1,350 '33 CcC2 Christiana silt loam, 5 to 10 percent slopes, moderately eroded -------------------------------------------------------- I1je-42 430 B3 CdC3 Christiana clay, S to 10 percent slopes, severely eroded -------- IVe-3 440 B3 Ce Coastal beaches -------------------------------------------------- VIIIS-2 280 A2 Ch Codorus silt loam ----------------------------------------------- 11w-7 150 G1 C1, Colomantown sandy loam ------------------------------------------ I11w-1 1,390 F3 Cm Colemantown silt loam ------------------------------------------- IIIW-7 730 F3 CnB2 Collington loamy sand, 2 to 5 percent slopes, moderately eroded -------------------------------------------------------- JIS-L 750 Bla CnC: Collington loamy, sand, 5 to 10 percent slopes, moderately eroded -------------------------------------------------------- Ille-33 65o BI& COA Collington fine sandy loam, 0 to 2 percent siopesz -------------- 1-5 390 31a CoB.7 Collington fine sandy loam, 2 to 5 percent slopes, moderately eroded -------------------------------------------------------- lIe-"-; 4,250 1@la CoC2 Collington fine sandy loam, 5 to 10 percent slopes, moderately eroded -------------------------------------------------------- 111e-5 1,63o Bla C-D'--3 Collington fine sandy loam, 5 to 10 percent slopes, severely ero 'ded -------------------------------------------------------- IVe-5 2,700 Bla CoD2 Collington fine sandy loam, 10 to 15 percent slopes, moderately eroded -------------------------------------------------------- IVe-5 960 Blb CoN Collington fine sandy loam, 10 to 15 percent slopes, severely eroded ------------------ I ------------------------------------- VIe-2 1,6W 31b COL Collington fine sand), loam, 15 to-40 percent slopes ------------- VIe-2 5,400 Blc C--'@ Collington silt loam, 0 to 2 percent ---------------------------- 1-4 130 Bla CpB2 Collington silt loam, 2 to 5 percent slopes, moderately eroded-- lIe-4 460 Bla CpuB Collington-Urban land complex, 0 to 5 percent slopes ------------ 640 31a CpuL', Collington-Urban land complex, 5 to 15 percent slopes ----------- ----- 470 Blb Cr Comus silt loam ------------------------------------------------- 1-6 110 31 CsC2 Croom gravelly sandy loam, S to 10 percent slopes, moderately eroded -------------------------------------------------------- JI19-9 700 B2&. CsV: Croor, gravelly sandy loam, 10 to 15 percent slopes, moderately eroded ----------- I -------------------------------------------- IVe-7 430 32b 77, A. A. Co. J J 0 0 (K L M W :) _j MAP I it 't Z >- U SYMBOL MAPPING UNIT U 3 0 It Z in o Cs' Croom gravelly sandy loam, 11 to 40 percent slopes -------------- VII 0 -1 340 B1c ,CtD Croom-Urban land complex, 5 to 15 percent slopes ---------------- ------ 360 B2b CuB Cut and fill land, 0 to 5 percent slopes ------------------------ ------ 4,500 Ma CuD Cut and fill land, 5 to 15 percent slopes ----------------------- ------ 910 Ma CuE Cut and fill land, 15 to 30 percent slopes ---------------------- ------ 250 Ma DnA Donlonton fine sandy loam, 0 to 2 percent slopes ---------------- !Iw-9 1,170 E2a DnB2 Donlonton fine sandy loam, 2 to 5 percent slopes, moderately eroded -------------------------------------------------------- IIe-36 1,390 B2a DuB Donlonton-Urban land complex, 0 to S percent slopes ------------- ------ 340 E2a Ek Elkton sandy loam ----------------------------------------------- jjjw-jj 530 F3 En Elkton silt loam ------------------------------------------------ JjIw-q 7,330 F3 EoB Evesboro loamy sand, 0 to 6 percent slopes ---------------------- ivs-1 21,04@ Ala ErB Evesboro loamy sand, clayey substratum, 0 to 5 percent slopes --- T71S-1 LI, 2@1'0 A.L& ErC Evesboro loamy sand, clayey substratum, 5 to 10 percent slopes-- IVs-1 550 k1a EsC Evesboro and Galestown loamy sands, 6 to 12 percent slopes ------ VIIs-1 6,600 Alb EsE Evesboro and Galestown loamy sands, 12 to 40 percent slopes ----- VIIs-1 4,710 A:Lc EuC Evesboro-Urban land complex, 0 to 15 percent slopes ------------- ------ 5,130 Alb. Fa Fallsington sandy loam@L ----------------------------------------- IIIw-6 1,370 F2 GaB Galestown loamy sand, 0 to 5 percent slopes --------------------- 1Vs-1 4,530 Ala Gp Gravel and borrow pits ------------------------------------------ VIIIs-4 1,760 BP ha Hatboro silt loam ----------------------------------------------- IIIW-7 1,100 G2 HfB2 Howell fine sandy loa 'm, I to 6 percent slopes, moderately eroded -------------------------------------------------------- IIe-28 48o 32a HgB2 Howell fine sandy loam, shaly subsoil, 2 to 6 percent slopes, moderately eroded --------------------------------------------- !Ie-28 120 B2a HsB2 Howell silt loam, 2 to 6 percent slopes, moderately eroded ------ :Ie-29 2@O 32a HtB2 Howell silt loam, shaly subsoil, 2 to 6 percent slope.s, moaerately eroded --------------------------------------------- lIe-29 230 B2a HyC3 Howell clay loam, 6 to 12 percent slopes, severely eroded ------- IVe-3 1,020 B2b HyD3 Howell clay loam, 12 to 20 percent slopes, severely eroded ------ Vle-2 800 B2c HyE3 Howell clay loam, 20 to 40 percent slopes, severely eroded ------ VIIe-2 Vo B2c HzC3 Howell clay loam, shaly subsoil, 6 to 12 percent slopes, severely eroded ----------------------------------------------- Ive-3 270 B2b KeA Keyport sandy loam, 0 to 2 percent slopes ----------------------- 11w-9 420 E2a KeB Keyport sandy loam, 2 to 5 percent slopes ----------------------- IIe-36 1,370 E2a KpA Keyport sandy loam,0 to 2 percent slopes ------------------------ IN-8 )80 E2a KpB2 Keyport silt loam, 2 to 5 percent slopes, moderately eroded ----- ile-13 1,390 E2a KrB Keyport-Urban land complex, 0 to S percent slopes --------------- ------ 350 E2a KS Klej loamy sand ------------------------------------------------- IIIw-10 650 El LoB Loamy and clayey land, 0 to 5 percent slopes -------------------- Me-42 5,830 B3 LoC Loamy and clayey land, 5 to 10 percent slopes ------------------- IVe-3 4,300 B3 LoD Loamy and clayey land, 10 to 40 percent slopes ------------------ VIe-2 2,270 B3 Ma lade land ------------------------------------------------------- ------ 100 Ma MfB2 Marr fine sandy loam, 2 to 6 percent slopes, moderately eroded-- IIe-5 7,750 Bla MfC2 Marr fine sandy loam, 6 to 12 percent slopes, moderately eroded -------------------------------------------------------- Me-5 1,120 Blb MfC3 Marr fine sandy loam, 6 to 12 percent slopes, severely eroded --- M-Ir: 7,800 31b MfD2 Marr fine sandy loam, 12 to 20 percent slopes, moderately eroded -------------------------------------------------------- 176-5 840 Ble MfD3 Marr fine sandy loam, 12 to 20 percent slopes, severely eroded-- VIe-2 h,250- Ble MfE3 Marr fine sandy loam, 20 to 35 percent slopes, severely eroded-- VIIe-2 1,090 310 RkA Matapeake fine sandy loam, 0 to 2 percent slopes ---------------- 1-5 100 Bla MkB2 Matapeake fine sandy loam, 2 to 5 percent slopes, moderately eroded -------------------------------------------------------- IIe-5 200 Bla NhA Matapeake silt loam, 0 to 2 percent slopes ---------------------- 1-4 390 31a, Mm132 Matapeake silt loam, 2 to'S percent slopes, moderately eroded --- IIe-4 330 Bla A. A. Co. J J re 0 (A a L MAP i t as 11Kd D.J 0 4 Z >. U M SYMBOL MAPPING UNIT U 3 0 4 Z 0 t3 MmC2 Matapeake silt loam, 5 to 10 percent slopes, moderately eroded-- me-L 400 lala NtT,C3 Matapeake silt loam, 5 to 10 percent slopes, severely eroded ---- 17e-3 230 Bla NImD3 Matapeake silt loam, 10 to 15 percent slopes, severely eroded --- VIe-2 230 Blb MnA Matawan loamy fine sand, 0 to 2 percent slopes ------------------ IIW-10 210 E2a MnB Matawan loamy fine sand, 2 to 5 percent slopes ------------------ IIe-36 420 E2a M,-A Mattapex fine sandy loam, 0 to 2 percent slopes ----------------- iiw-5 130 E3a MpB2 Mattapex fine sandy loam, 2 to 5 percent slopes, moderately eroded -------------------------------------------------------- lIe-36 220 E3a 11iA Mat,apex silt loam, I to 2 percent slopes ----------------------- IIW.;l 2 230 E3a .MrB2 Mattapex silt loam, 2 to 5 percent slopes, moderately eroded ---- Ile-15 1,?4o Z-3a MrC2 Mattapex silt loam, 5 to 10 percent slopes, moderately eroded--- Me-16 420 E3a Mt Mixed alluvial land --------------------------------------------- VIW-l L, "?50 G2 MuA Monmouth loamy sand, 0 to 2 percent slopes ---------------------- iis-5 340 B2a Nlu B 2 Monmouth loam), sand, 2 to 5 percent slopes, moderately eroded --- :is-5 4,520 32a Nlu@2 Monmouth loamy sand, 5 to 10 percent slopes, moderately eroded-- Me-: )90 B2a M.;C3 Monmouth loamy sand, S to 10 percent slopes, severely eroded ---- IVe-5 950 B2a MuD2 Monmouth loamy sand, 10 to 15 percent slopes, moderately eroded -------------------------------------------------------- ivd-r-' 450 B2`b N1uD3 Monmouth loamy sand, 10 to 15 percent slopes, severely eroded --- Vle-2 570 B2b Mv A Monmouth fine sandv loam, 0 to 2 percent slopes ----------------- 1-23 460 52a Nh-EZ Monmouth fine sandy loam, 2 to 5 percent slopes, moderately eroded -------------------------------------------------------- IIe-2'-. 3,780 B2a MvC2 Monmouth fine sandy loam, 5 to 10 percent slopes, moderately eroded -------------------------------------------------------- IIIe-28 870 R2a MvD2 Monmouth fine sandy loam, 10 to 15 percent slopes, moderately eroded -------------------------------------------------------- ive-5 750 B2b Monmouth fine sandy loam, 15 to 40 percent slopes@ -------------- Vle-2 7,790 "12c NlwC,3 Monmouth clay loam, 5 to 10 percent slopes, severely eroded ----- 1'.'e-3 2,34o 132a MwD3 Monmouth clay loam, 10 to 15 percent slopes, severely eroded ---- VIe-2 1,040 B2b MxB Mormouth-Urban land complex, 0 to 5 percent slopes -------------- ----- 2,020 132a Kx D Monmouth-Urban land complex, 5 to 15 percent slopes ------------- 530 B2b MvE Muir@irk loamy sand, 0 to 5 percent slopes ---------------------- iis-5 2,4,)o 33 W Nh-C Muirkirk loamy sand, 5 to 10 percent slopes ------------ Me-5 31 33 Nivill Muirkirk loam\- sand, 10 to 15 percent slopes -------------------- Ne-'@. 410 B3 NlyE Muirkirk loamy sand, 15 to 30 percent slopes -------------------- 711e-2 260 33 M:B Muirkirk-Urban land complex, 0 to 5 percent slopes -------------- 870 B3 NJ: D Muirkirk-Urban land complex, 5 to 15 percent slopes ------------- ----- 230 B3 Os Osier loamy sand ------------------------------------------------ ivw-6 330 F1 Ot Othello silt loam ----------------------------------------------- IIN-7 4,o4b F3 RuA Rumford loamy sand, 0 to 2 percent slopes ----------------------- iis-4 1,050 Ala RuB2 Rumford loamy sand, 2 to S percent slopes, moderately eroded---- iis-4 3,500 Ala RuC2 Rumford loamy sand, 5 to 10 percent slopes, moderately eroded --- :Ile-33 1,540 Ala RuC3 Rumford 1 o am), sand, 5 to 10 percent slopes, severely eroded ----- Ive-5 1,420 Ala RuD2 Rumford loamy sand, 10 to 15 percent slopes, moderately eroded-- IVe-5 WO Alb Ry B Rumford-Urban land complex, 0 to 5 percent slopes --------------- ----- 1,350 Ala RyD Rumford-Urban land complex, 5 to 15 percent slopes -------------- 330 Alb aA Sassafras fine sandy loam, 0 to 2 percent slopes ---------------- 1-5 1,220 Sla SaB.' Sassafras fine sandy loam, 2 to 5 percent slopes, moderately eroded -------------------------------------------------------- ne-5 7,170 131a SaC2 Sassafras fine sandy loam, S to 10 percent slopes, moderately eroded -------------------------------------------------------- 111e-5 ?20 Bla SaC3 Sassafras fine sandy loam, 5 to 10 percent slopes, severely eroded -------------------------------------------------------- Ive-5 l'-)90 31a SaD2 Sassafras fine sandy loam, 10 to 15 percent slopes, moderately eroded -------------------------------------------------------- IVe-5 h6o '91b Sa[13 Sassafras fine sandy loam, 10 to 15 percent slopes, severely eroded -------------------------------------------------------- VIe-2 1,5?0 111b 79 A.A. Co. j 0 0 IK IL MAP SYMBOL MAPPING UNIT Val (25 U SaE Sassafras fine sandy loam, 15 to 40 percent slopes ------------- VIe-2 11910 31C .SfA Sassafras loam, 0 to 2 percent slopes -------------------------- 1-4 240 31a SfB2 Sassafras loam, 2 to 5 percent slopes, moderately eroded ------- ile-4 1,010 31a SnB Sassafras-Urban land complex, 0 to 5 percent slopes ------------ 050 I Bi& SnD Sassafras-Urban land complex, 5 to 15 percent slopes ----------- ----- 310 Blb Sr Shrewsbury fine sandy loam ------------------------------------- 111,.4-6 1,310 F2 Ss Shrewsbury silt loam ------------------------------------------- !Ilw-7 520 F2 SW Swamp ---------------------------------------------------------- VIIW-l 65 G3 Tm Tidal marsh ---------------------------------------------------- VII.'w-l 3,400 G3 Ur Urban land---7 ------------------------------------------------- ----- 69.0 Ma WaB2 Westphalia fine sandy loam, 2 to 6 percent slopes, moderately eroded ------------------------------------------------------- !Ie-5 1,320 Bla WaC2 Westphalia fine sandy loam, 6 to 12 percent slopes, moderately eroded ----------------------------------- ------------------- Me-5 510 Blb WaC3 Westphalia fine sandy loam, 6 to 12 percent slopes, severely eroded ------------------------------------------------------- lVe-5 3,210 31b WaD3 Westphalia fine sandy loam, 12.to 20 percent slopes, severely eroded ----------------------r -------------------------------- Vie-2 4,470 BIC WaE3 Westphalia fine sandy loam, 20 to 50 percent slopes, severely eroded ------------------------------------------------------- V71e-2 5,130 BIC WdA Woodstown sandy loam, 0 to 2 percent slopes -------------------- IIW-5 830 El WdB Woodstown sandy loam, 2 to 5 percent slopes -------------------- He-36 1,260 F1 WoA Woodstown loam, 0 to 2 percent slopes -------------------------- 11W_1 250 El WOB Woodstown loam, 2 to 5 percent slopes -------------------------- :le-16 250 El ----- - L64(1 Ma Total 266,880 80 BALTIMORE COUNTY j 0 0 X L M1 IWK n 3 >. U @ R MAP U Z V) 15 SYMBOL MAPPING UNIT AdA Aldino silt loam, 0 to 3 percent slopes ---------------------- Hv-2 380 E2& AdB2 Aldino silt loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- He-14 2,170 E2a AdC2 Aldino silt loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- Me-14 370 E2b A@C Altino very stony silt loam, 0 to 15 percent slopes ---------- VIs-3 190 Hlb AuB Aldino-Urban land complex, 0 to 8 percent slopes ------------- ---- 1,020 E2a Av Alluvial land ------------------------------------------------ VIw-1 5,170 C2 BaA Baile silt loam, 0 to 3 percent slopes ----------------------- Vw-l 2,030 F3 BaB Baile silt loam, 3 to 8 percent slopes ----------------------- VIw-2 1,820 F3 BmA Baltimore silt loam, 0 to 3 percent slopes ------------------- 1-1 560 Bla BmB2 Baltimore silt loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- 1Ie-I 6,590 Bla. BmC2 Baltimore silt loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- Hle-1 1,480 Blb Bnd Baltimore-Urban land complex, 0 to 8 percent slopes ---------- 330 Bla Br Barclay silt loam -------------------------------------------- IIlw-1 1,680 F2 BLA Beltsville silt loam, 0 to 2 percent slopes ------------------ Hw-8 390 E2a BtB Beltsville silt loam, 2 to 5 percent slopes ------------------ He-13 3,350 E2& BtC2 Beltsville silt loam, 5 to 10 percent slopes, moderately eroded -------------------------------------------- Me-13 1,150 EU BUB Beltsville-Urban land complex, 0 to 5 percent slopes --------- ---- 1,670 E2a BUC Beltsville-Urban land complex, 5 to 10 percent slopes -------- ---- 450 E2a BwB2 Brandywine loam, 3 to 8 percent slopes, moderately eroded --------------------------------------------- He-10 790 Cla BwC2 Brandywine loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- Hle-10 1,700 Clb ByD2 Brandywine gravelly loam, 15 to 25 percent slopes, moderately eroded -------------------------------------------- IVe-10 1,000 CIC ByD.3 Brandywine gravelly loam, 15 to 25 percent slopes-,* 11 everely eroded ---------------------------------------------- VIe-3 690 Clc BYE Brandywine gravelly loam, 25 to 45 percent slopes ------------ VIe-3 890 Clc CaA Captina silt loam, 0 to 3 percent slopes --------------------- Ilw-I 420 E2a CaB2 Captina silt loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- Ile-16 620 E2a CcA Chester silt loam, 0 to 3 percent slopes --------------------- 1-4 330 Bla CcB2 Chester silt loam, 3 to 8 percent slopes, moder@ately eroded -------------------------------------------- Ile-4 18,020 Bla CcC2 Ches-ter silt loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- IIIe-4 3,490 Blb CSB2 Chester gravelly silt loam, 3 to 8 percent slopes, moderately eroded --------------------------------------------- Ne-4 3,160 Bla CgC2 Chester gravelly silt loam, 8 to 15 percent slopes, moderately eroded --------------------------- w ------ a----------- IIie-4 2,720 Blb ChB2 Chillum silt loam, 2 to 5 percent slopes, moderately eroded -------------------------------------------- IIS-7 1,340 B2a ChC2 Chillum silt loam, 5 to 10 percent slopes, moderately eroded -------------------------------------------- IIIe-7 610 B2a ChC3 Chillun silt loam, 5 to 10 percent slopes, severely eroded ---------------------------------------------- IVe-7 190 B2a CkB2 Chillum-Neshaminy silt loams, 2 to 5 percent slopes, moderately eroded ---------------------------------------------- 118-7 690 B2a. CkC2 Chillum-Neshaminy silt loams, 5 to 10 percent slopes, moderately eroded -------------------------------------------- Me-7 570 B2a CkD2 Chillum-Neshaminy silt loams, 10 to 15 percent slopes, moderately eroded -------------------------------------------- lVe-7 250 B2b cib Chillum-Urban land complex, 0 to 5 percent slopes ------------ ---- 1,450 B2a CID Chillum-Urban land complex, 5 to 15 percent slopes ----------- ---- 1,030 B2b Bait. Co. t J j F1 0 fa it L .4 P- Is 1 3 3 L J MAP 4 Z >. 0 @ 8) 9 SYMBOL MAPPING UNrT U :j fA .4 Z 1A 0 CmB Christiana loam, 2 to 5 percent slopes ----------------------- Ile-42 740 B3 CmC2 Christiana loam, 5 to 10 percent slopes, moderately eroded -------------------------------------------- IlIe-42 480 B3 Cr111 Chrome silt loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- IIe-10 280 Cla CoC3 Chrome channery silty clay loam, 3 to 15 percent slopes, severely eroded ---------------------------------------------- VIS-32 1,010 Clb CoE3 Chrome channery silty clay loam, 15 to 45 percent slopes, 11 everely eroded ---------------------------------------------- VIIS-32 610 Clc Cp Clay pits ---------------------------------------------------- VIIIS-4 110 --- Ct Coastal beaches ---------------------------------------------- VIII9-2 60 A2 Cu Codorus silt loam -------------------------------------------- IIw-7 9,200 G1 Cv Comus silt loam ---------------------------------------------- 1-6 810 G1 .CwB2 Conestoga loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- IlIe-24 4,700 Bla CwC2 Conestoga loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- IIIe-24 2,140 Blb DcB Delanco silt loam, 3 to 8 percent slopes --------------------- He-16 940 E2a Du Dunning silt loam -------------------------------------------- IVW-3 630 G2 EdB2 Edgemont gravelly loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- He-4 200 Bla EdC2 Edgemont gravelly loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- IIIe-4 280 Blb EgD Edgemont very stony loam, 8 to 25 percent slopes ------------- Vls-3 360 Hlc .EgE Edgemont very stony loam, 25 to 45 percent slopes ------------ VIIs-3 440 Hlc EhB2 Elioak silt loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- Ile-4 4,180 Bla EhC2 Elioak silt loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- Hle-4 510 Blb EkE2 Elioak gravelly silt loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- He-4 450 Bla EkC2 Elioak gravelly silt loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- IIIe-4 250 Blb ElC3 Elioak silty clay loam, 8 to 15 percent slopes, severely eroded ---------------------------------------------- IVe-3 190 Blb Em Elkton loam -------------------------------------------- * ------ 11Iw-9 290 F3 En Elkton silt loam --------------------------------------------- IIIw-9 640 F3 Eo Elkton-Urban land complex ------------------------------------ --- 220 F3 EsB Elsinboro loam, 3 to 8 percent slopes ------------------------ Ile-4 1,270 Bla EsC2 Elsinboro loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- IlIe-4 450 Blb Fa Fallaington sandy loam --------------------------------------- lIlw-6 600 F2 Fs Fallsington loam - ------------------------------------------- IIIw-7 920 F2 FtB Fort Mott loamy sand, 0 to 5 percent slopes ---------- ------- lls-4 570 Ala GaB Galestown loamy sand, 0 to 5 percent slopes ------------------ IIIs-1 230 Ala Gac Calestown loarny sand, 5 to 10 percent slopes ----------------- IVs-l 160 Ala GcB2 Glenelg loam, 3 to 8 percent slopes, moderately eroded ------- He-4 24,400 Bla GcC2 Clenelg loam, 8 to 15 percent slopes, moderately eroded ------ IIIe-4 17,850 Blb GcC3 Glenelg loam, 8 to 15 percent slopes, severely eroded -------- IVe-3 2,030 Blb GcD2 Glenelg loam, 15 to 25 percent slopes, moderately eroded --------------------------- ----------------- IVe-3 1,440 Blc GcD3. Clenelg loam, 15 to 25 percent slopes, severely eroded ---------------------------------------------- VIe-3 740 Blc CgB2 ClenelS channery loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- He-4 2,0.70 Bla GgC2 Glenelg channery loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- lIle-4 5,180 Blb GgD2 Glenel& channery loam, 15 to 25 percent slopes, moderately eroded -------------------------------------------- IVe-3 1,740 Blc 82 Balt. Co. t J a .4 L oa- n t I MAP 't Z >. u 462 SYMBOL MAPPING UNrr U 3 a 4 Z V1 0 GgD3 Glenelg channery loam, 15 to 25 percent slopes, severely eroded ---------------------------------------------- VIe-3 1,120 BIC GIB Gleneig-Urban land complex, 0 to 8 percent slopes ------------ ---- 3,210 Bla GIC Gleneig-Urban land complex, 8 to 15 percent slopes ----------- ---- 1,370 Blb GnA Glenville silt loam, 0 to 3 percent slopes ------------------- 1Iw-I 1,900 E2a GnB Glenville silt loam, 3 to 8 percent slopes ------------------- IIe-16 12,030 E2& GuB Glenvill6-Urban land complex, 0 to I percent slopes ---------- --- 310 Fla H@aA Hagerstown silt loam, 0 to 3 percent slopes ------------------ 1-1 280 Bla HaB2 Hagerstown silt loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- Ile-1 1,410 Bla HaC2 Hagerstown silt loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- lIle-1 430 Blb Hb Hatboro silt loam -------------------------------------------- IlIw-7 4,160 G2 HoB2. Hollinger loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- IIe-25 360 Bla HoC2 Hollinger loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- IlIe-25 500 Blb HrD3 Hollinger and Conestoga loams, 15 to 25 percent slopes, severely eroded ---------------------------------------------- Vle-3 360 Blc HsC Hollinger and Conestoga very rocky loams, 3 to 15 percent slopes ------------------------------------------------------- VI8-2 550 H2b lu luka silt loam ----------------------------------------------- lIw-7 530 G1 JPB Joppa gravelly sandy loam, 2 to 5 percent slopes ------------- IIs-4 960 Ala JpC2 Joppa gravelly sandy loam, 5 to 10 percent slopes, moderately eroded -------------------------------------------- IIIe-33 1,370 Ala JpD2 Joppa gravelly sandy loam, 10 to 15 percent slopes, moderately eroded -------------------------------------------- IVe-5 490 Alb JuD Joppa-Urban land complex, 5 to 15 percent slopes ------------- ---- 1,510 Alb KeB2 Kelly silt loam, 3 to 8 percent slopes, moderately eroded ---- IVw-3 890 F3 KeC2 Kelly silt loam, 8 to 15 percent slopes, moderately eroded --- 1Vw-3 240 F3 ..KSC Kelly very stony silt loam, 0 to 15 percent slopes ----------- VIIs-4 240 Hlb KUB Kelly-Urban land complex, 0 to 8 percent slopes -------------- --- 300 F3 LeB2 Legore silt loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- Ile-10 1,170 Bla LeC2 Legore silt loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- Me-10 1,310 Blb LeD2 Legore silt loam, 15 to 25 percent slopes, moderatel y eroded -------------------------------------------- Ne-10 770 Blc LeE Legore silt loam, 25 to 45 percent slopes -------------------- Vje-3 430 Blc LfC Legore very stony silt loam, 3 to 15 percent slopes ---------- VIS-3 1,650 Hlb LfD Legore very stony silt loam 15 to 25 percent slopes --------- VIs-33 1,140 Hlc LfE Legore very stony silt loam: 25 t@ 45 percent slopes --------- VIIs-3 1,290 Hlc LgC3 Legore silty clay loam, 8 to 15 percent slopes, severely eroded ---------------------------------------------- IVe-10 750 Blb LgD3 Legore silty clay loam, 15 to 25 percent slopes, severely eroded ---------------------------------------------- VIe-3 690 Blc LhB Legore-Urban land complex, 0 to 8 percent slopes ------------- ---- 3,260 Bla LhC Legore-Urban land complex, 8 to 15 percent slopes ------------ ---- 1,800 Blb LIB Lenoir loam, 0 to 5 percent slopes --------------------------- IIIw-5 940 F3 LmB Lenoir silt loam, 0 to 5 percent slopes ---------------------- IIIw-5 2,140 F3 LmC2 Lenoir silt loam, 5 to 12 percent slopes, moderately eroded -------------------------------------------- IIIe-34 270 F3 LnC3 Lenoir silty clay I.am, 5 to 12 percent slope., 11 everely eroded ---------------------------------------------- IVe-9 280 F3 LoB L:noir-Urban land complex, 0 to 5 percent -------------------- ---- 740 F3 Lr L onardtown silt loam ---------------------------------------- 1Vv-3 560 F3 Ls Lindside silt loam ------------------------------------------- 11w-7 510 G1 LvB Loamy and clayey land, 0 to 5 percent slopes ----------------- IlIe-42 3,460 B3 83 Balt. Co. F1 0 0 X (L f t J .9 z MAP U 3 PYMBOL MAPPING UNIT 4 Z tn 0 LyD Loamy and clayey land, 5 to 15 percent slopes ---------------- VIe-2 6,570 B3 LyE Loamy and clayey land, 15 to 40 percent slopes --------------- VIle-2 590 B3 Ma Made land ---------------------------------------------------- ---- 3,600 Ma KbB2 Manor loam, 3 to 8 percent slopes, moderately eroded --------- IIe-25 8,810 Bla .MbC2 Manor loam, 8 to 15 percent slopes, moderately eroded -------- IIIe-25 20,090 Bib MbC3 Manor loam, 8 to 15 percent slopes, severely eroded ---------- IVe_25 3,360 Bib MbD2 Manor loam, 15 to 25 percent slopes, moderately eroded ------- IVe-3 6,830 Bic MbD3 Manor loam, 15 to 25 percent slopes, severely eroded --------- VIe-3 6,830 Bic McB2 Manor channery loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- IIe-25 3,140 Bla McC2 Manor channery loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- IlIe-25 12,270 Bib McC3 Manor channery loam, 8 to 15 percent slopes, severely eroded ---------------------------------------------- Ive-25 2,010. Bib McD2 Manor channery loam, 15 to 25 percent slopes, moderately eroded -------------------------------------------- IVe-25 11,700 Bic McD3 Manor channery loam, 15 to 25 percent slopes, severely eroded ---------------------------------------------- VIe-3 8,300 Bic MdE Manor soils, 25 to 50 p@rcent slopes ------------------------- VIe-3 16,310 Bic MeD Manor-Urban land complex, 15 to 25 percent slopes ------------ ---- 350 Bic MgC Manor and Glenelg very stony.loams, 3 to 15 percent slopes ------------------------------------------------------- VIs-3 570 Hlb MhD Manor and Brandywine very stony loams, 15 to 25 percent slopes ------ o ----------------------------------------- VIs-3 1,000 Hlc MhE Manor and Brandywine very stony loams, 25 to 65 percent slopes ----------------------------------------------- VlIs-3 8,000 Hlc MkA Matapeake silt loam, 0 to 2 percent slopes ------------------- 1-4 240 Bla Mk8 Matapeake silt loam, 2 to 5 percent slopes ------------------- IIe-4 670 Bla MkC2 Matapeake silt loam, 5 to 12 percent slopes, moderately eroded ----------- --------------------------------- Ille-4 260 Bla MIA Mattapex silt loam, 0 to 2 percent slopes -------------------- IIw-1 1,940 E3a MIB Mattapex silt loam, 2 to 5 percent slopes -------------------- He-16 3,170 E3a MmB Mattapex-Urban land complex, 0 to 5 percent slopes ----------- ---- 3,740 E3a Mh Melvin silt loam --------------------------------------------- IIIw-3 330 G2 Mo Melvin silt loam, local alluvium ----------------------------- IIIw-3 1,210 C2 Mr Mine dumps and quarries -------------------------------------- VIIIS-4 120 -- MsB2 Montalto silt loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- Ile-4 1,690 B2a MsC2 Montalto silt loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- IIIe-4 390 B2b MtB2 Mt. Airy channery loam, 3 to 8 percent slopes, moderately eroded ------------------------------------------------------- IIIe-10 380 Cla MtC2 Mt. Airy channery loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- IVe-10 1,690 Clb MtD2 Mt. Airy channery loam, 15 to 25 percent slopes, moderately eroded -------------------- ; ------------------------ Vle-3 1,440 Clc MtD3 Mt. Airy channery loam, 15 to 25 percent slopes, severely eroded ---------------------------------------------- VIIe-3 1,250 Clc NeB2 Neshaminy silt loam, 3 to 8 percent slopes, moderately eroded ------- ------------------------------------ IIe-4 2,730 Bia NeC2 Neshaminy silt loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- IlIe-4 950 Bib Ot Othello silt loam -------------------------------------------- IIIw-7 820 F3 Po Pocomoke sandy loam ------------------------------------------ IIIW-6 110 F2 ReC2 Relay silt loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- IIIe-10 330 Clb ReD2 Relay silt loam, 15 to 25 percent slopes, moderately eroded -------------------------------------------- lVe-10 150 Clc RsD Relay very stony silt loam, 3 to 25 percent slopes ----------- VIs-3 230 Ric 84 Balt. Co. A j 0 a it L MAP SYMBOL MAPPING UNIT 4 Z one .4 W 0 RsE Relay very stony silt loam, 25 to 65 percent slopes ---------- VIls-3 640 Hlc RyD3 Relay clay loam, 15 to 25 percent slopes, severely eroded ---------------------------------------------- Vle-3 310 Clc Sg Sand and gravel pits ----------------------------------------- V1118-4 1,240 --- ShA Sassafras sandy loam, 0 to 2 percent slopes ------------------ 1-5 1,060 Bla ShB Sassafras sandy loam, 2 to 5 percent slopes ------------------ Ile-5 2,970 Bla ShC2 Sassafras sandy loam, 5 to 10 percent slopes, moderately eroded -------------------------------------------- Ille-5 610 Bla ShC3 Sassafras sandy loam, 5 to 10 percent slopes, everely eroded ---------------------------------------------- IVe-5 210 Bla ShD2 Slassafras sandy loam, 10 to 15 percent slopes, moderately eroded ------------------- ------------------------ IVe-5 310 Bla SIA Sassafras loam, 0 to 2 percent slopes ------------------------ 1-4 490 Bla .SIB Sassafras loam, 2 to 5 percent slopes ------------------------ IIe-4 1,020 Bla SIC2 Sassafras loam, 5 to 10 percent slopes, moderately eroded ---- IIIe-4 350 Bla SnB Sassafras-Urban land complex, 0 to 5 percent slopes ---------- ---- 5,170 Bla SsD3 Sassafras and Joppa soils, 5 to 15 percent slopes, severely eroded ---------------------------------------------- VIe-2 640 Blb SSE Sassafras and Joppa soils, 15 to 30 percent slopes ----------- VIe-2 420 Blc St Stony land, steep -------------------------------------------- VIlls-I 1,670 Hlc SuB2 Sunnyside fine sandy loam, 0 to 5 percent slopes, moderately eroded -------------------------------------------- IIe-5 250 Bla SW Swamp -------------------------------------------------------- VIIw-l 180 G3 Tm Tidal marsh -------------------------------------------------- VIIIw-l 2,S20 G3 WaA Watchung silt loam, 0 to 3 percent slopes -------------------- V-1 750 F3 .WaB Watchung silt loam, 3 to 8 percent slopes -------------------- VIw-2 700 F3 WCB Watchung very stony silt loam, 0 to 3 percent slopes --------- VIIs-4 530 Hla WdA Woodstown sandy loam, 0 to 2 percent slopes ------------------ IIw-5 1,810 El WdB Woodstown sandy loam, 2 to 5 percent slopes ------------------ He-36 1,090 El WoA Woodstown loam, 0 to 2 percent slopes ------------ ------------ Ilw-l 910 El WOB Woodstown loam, 2 to 5 percent slopes ------------------------ IIe-16 650 El Paved Areas ------------------------------------------------ ---- 540 --- Total 400 85 CARROLL COUNTY 0 W W. L MAP z 0 SYMBOL MAPPING UNIT U 3 a 44 Z (A f3 ArA Abbottstown and Readington silt loams, 0 to 3 percent slopes ----------------------------------------------- IIIW-1 3,302 F3 ArB2 Abbottstown and Readington silt loams, 3 to 8 percent slopes, moderately eroded ---------------------------- Jjjw-j 1,812 F3 B&A Baile silt loam, 0 to 3 percent slopes ----------------- Vw-1 3.435 F3 BaB Eaile silt loar-, 3 to 8 percent slopes: ---------------- VIW-2 2,657 F3 Be Bermudian silt loam ------------------------------------ 1-6 602 G1 BrA Birdsboro silt loam '0 to 3 percent slopes ------------- 1-4 325 Bla BrB2 Birdsboro silt loan., 3 to 8 percent slopes, moderately eroded ----------------------------------------------- lIe-4 4214 Bla Bs Bowmansville silt loam --------------------------------- IIN-7 544 G2 -BuA Bucks silt loarn, 0 to 3 percent slopes ----------------- ;-4 515 32a BuB2 Bucks silt loam, 0 to 8 percent slopes, moderately eroded ----------------------------------------------- lIe-4 2,503 B2& CaC2 Cardiff channery silt loam, 3 to 15 percent slopes, moderately em ded ------------------------------------ IIJO-10 245 Clb CeA Chestef silt loam, 0 to, 3 percent slopes --------------- 1-4 500 131& CeB2 Chester silt loam, 3 to 8 percent slopes, moderately eroded ------------------------------------------------ lIe-4 6,357 Bla CeC2 Chester silt lour., 8 to 15 percent slopes, moderately eroded ----------------------------------------------- Me-4 759 Blb CeC3 Chester silt loajr., S to 15 percent slopes, severely eroded ----------------------------------------------- 378-3 165 Blb Ch Codorus silt loa-m -------------------------------------- IIW-@7 4.823 G1 Cm Comus silt lcam ---------------------------------------- 1-6 256 G1 CnA Corrrus silt loazm, local alluvium, 0 to 3 percent slopes- 1-6 231 al CrIB Comus silt loan, local alluvium, 3 to 8 percent slopes-, JIe-6 1,232 'CoA Conestoga silt loam, 0 to percent slopes ------------- 1-1 232 91a CoB2 Conestoga silt 1:;am, 3 to percent slopes, moderately eroded - --------------------------------------------- lIe-24 1,630 31a CoC2 %nestoga. silt loam, 8 to 15 percent slopes, moderately eroded ----------------------------------------------- Me-24 793 Blb COC3 Conestoga silt loanzi, 8 to 15 percent slopes, severely eroded ----------------------------------------------- Ive-1 145 Blb CoD3 Conestoga silt loam, 15 to 25 percent slopes, severely eroded ----------------------------------------------- VIG-1 191 Ble DeA Delanco silt loarn, 0 to 3 percent slopes --------------- JIw-1 332 E3a DeB2 Delanco silt loam, 3 to 8 percent slopes, moderately eroded ----------------------------------------------- lIe-16 356 EU EIB2 Elioak silt loWn, 3 to B percent slopes, moderately eroded ----------------------------------------------- - 1Ie-4 1,179 Bla ElC2 Elioak silt loam, 8 to 15 percent slopes,.moderately eroded ----------------------------------------------- Ine-4 335 31b EmD3 Elioak silty clay loam, 15 to 25 percent slopes, severely eroded -------------------------------------- VI9-2 95 Ble EnB2 Elsinboro gravelly loam, 3 to 8 percent slopes, moderately eroded ------------------------------------ iie-4 1,156 Bla EnC2 Elsinboro gravelly loam, 8 to 15 percent slopes, moderately eroded ------------------------------------ JJJQ-4 691 E11b E&A Elsinboro silt loam, 0 to 3 percent slopes ------------- 1-4 91 31a EsB2 Elsinboro silt loam, 3 to 8 percent slopes, moderately eroded ----------------------------------------------- JIS-4 1,oo6 131a EsC2 Elsinboro silt loam, 8 to 15 percewit slopes, moderately eroded ----------------------------------------------- IIJO-4 365 31b Carroll Co. MAP SYMBOL MAPPING UNIT ZOO GcB2 Glenelg channery loam, 3 to 8 percent slopes, moderately eroded ------------------------------------ IIe-4 11,405 Bla Glenelg channery loam, 8 to 15 percent slopes, mod- erately eroded --------------------------------------- IIIe-4 6,754 Bld 754 Blb GcC3 Glenelg channery loam, 8 to 15 percent slopes, severely eroded ----------------------------------------------- IVe-3 1,891 Blb GcC2 Glenelg channery loam, 15 to 25 percent slopes, moderately eroded ------------------------------------ IVe-3 1,093 Blc GcD3 Glenelg channery loam, 15 to 25 percent slopes, severely eroded -------------------------------------- Vle-2 1,330 Ble GlA Glenelg loam, 0 to 3 percent slopes -------------------- I-4 631 Bla GlB2 Glenelg loam, 3 to 8 percent slopes, moderately eroded- IIe-4 12,991 Bla GlB3 Glenelg loam, 3 to 8 percent slopes, severely eroded IIIe-4 706 Bla GlC2 Glenelg loam, 8 to 15 percent slopes, moderately eroded ----------------------------------------------- IIIe-4 5,299 Blb GlC3 Glenelg loam, 8 to 15 percent slopes, severely eroded-- IVe-3 2,062 Blb GvA Glenville silt loam, 0 to 3 percent slopes IIw-2 2,477 E2a Gv3 Glenville silt loam, 3 to 8 percent slopes IIe-13 8,015 E2a HaA Hagerstown silt loam, 0 to 3 percent slopes J-1 98 Bla HaB2 Hagerstown silt loam, 3 to 8 percent slopes, moderately eroded ----------------------------------------------- IIe-1 999 Bla HaC2 Hagerstown silt loam, 8 to 15 percent slopes, moderately eroded ------------------------------------ IIIw-1 131 Blb Ht Hatboro silt loam -------------------------------------- IIIw-7 6,258 G2 K1B Klinesville gravelly loam, 3 to 8 percent slopes, moderately eroded ------------------------------------ IVs-32 268 Dla KsD4 Klinesville soils, 8 to 25 percent slopes, very severely eroded -------------------------------------- VIIs-32 698 Dlc KsB3 Klinesville soils, 15 to 65 percent slopes, severely eroded ----------------------------------------------- VIIs-32 2,165 D1c LbB2 Lewisberry gravelly fire sandy loam, 3 to 8 percent slopes, moderately eroded ---------------------------- IIs-2 453 Bla LbC2 Lewisberry gravelly fine sandy loam, 8 to 15 percent slopes, moderately eroded ---------------------------- IIIe-5 765 Blb LbD Lewisberry gravelly fine sandy loam, 15 to 25 percent slopes ----------------------------------------------- IVe-5 161 Blc Le Lindside silt loan -------------------------------------- IIW-7 842 Gi LnB2 Linganore channery silt loam, 3 to 8 percent slopes, moderately eroded ------------------------------------ IIIe-10 1,439 Cla LnC2 Linganore channery silt loam, 8 to 15 percent slopes, moderately eroded ------------------------------------ IVe-10 2,138 Clb LnC3 Linganore channery silt loam, 8 to 15 percent slopes, severely eroded -------------------------------------- VIe-3 427 Clb LnD2 Linganore channery silt loam, 15 to 25 percent slopes, moderately eroded ------------------------------------ VIe-3 1,168 Clc LnE Linganore cbannery silt loamn, 25 to 45 percent slopes-- VIIe-3 1,628 C1c Md Made land ---------------------------------------------- 324 Ma MgB2 Manor gravelly loam, 3 to 8 percent slopes, moderately eroded ----------------------------------------------- IIe-25 2,473 Bla MgC2 Manor gravelly loam, 8 to 15 percent slopes, moderately eroded ----------------------------------------------- IIIe-25 3,204 Blb MgC3 Manor gravelly loam, 8 to 15 percent slopes, severely eroded ----------------------------------------------- IVe-25 1,508 Blb MgD2 Manor gravelly loam, 15 to 25 percent slopes, moderate- ly eroded -------------------------------------------- IVe-25 983 Blc 91 Carroll Co. MAP SYMBOL MAPPING UNIT MgD3 Manor gravelly loam, 15 to 25 percent slopes, severely 0 MAP SYMBOL MAPPING UNIT MgD3 Manor gravelly loam, 15 to 25 percent slopes, severely eroded -------------------------------------------- VIe-3 1,641 Blc MIB2 Manor loam, 0 to 8 percent slopes, moderately eroded-- IIe-25 8,883 Bla MlB3 Manor loam, 3 to 8 percent slopes, severely eroded---- IIIe-25 2,381 Bla MlC2 Manor loam, 8 to 15 percent slopes, moderately eroded- IIIe-25 5,.583 Blb MlC3 Manor loam, 8 to 15 percent slopes, severely eroded--- IVe-25 4,653 Blb MlD2 Manor loam, 15 to 25 percent slopes, moderately eroded ---------------------------------------------- IVe-25 1,817 Blc MID3 Manor loam, 15 to 25 percent slopes, severely eroded-- VIe-3 3,874 B1C MlD3 Manor loam, 15 to 25 percent slopes, severely eroded VIe-3 3,871 Blc MlE Manor loam, 25 to 45 percent slopes ------------------- VIIe-3 3,791 Blc MnC Manor very stony loam, 3 to 15 percent slopes---------- V1-3 1,418 Hlb MnD Manor very stony loam, 15 to 25 percent slopes--------- VIs-3 1,306 H1c MnE Manor very stony loam, 25 to 45 percent slopes--------- VIIs-3 2,942 Hle MnF Manor very stony loam, 45 to 75 percent slopes--------- VIIs-3 933 Hlc Mo Melvin silt loam -------------------------------------- IIIw-3 270 G2 MtA Mt. Airy channery loam, 0 to 3 percent slopes ---------- IIIs-1 209 Cla MtB2 Mt. Airy channery loam 3 to 8 percent slopes, moderately eroded -------------------------------- IIIe-10 19.291 Cla MtC2 Mt. Airy channery loam, 8 to 15 percent slopes, moderately eroded -------------------------------- IVe-10 34,489 Clb MtC3 Mt. Airy channery loam, 8 to 15 percent slopes, severely eroded ----------------------------------- VIe-3 5,836 Clb MtD2 Mt. Airy channery loam, 15 to 25 percent slopes, moderately eroded -------------------------------- VIe-3 13,635 Clc MtE Mt. Airy channery loam, 25 to 45 percent slopes -------- VII-3 22,182 Cle PeB2 Penn loam, 0 to 8 percent slopes, moderately eroded ---- IIe-10 4.720 Cla PhB2 Penn shaly silt loam, 3 to 8 percent slopes, moderately eroded -------------------------------- IIIe-10 5,051 Dla PhC2 Penn shaly silt loam, 8 to 15 percent slope., moderately eroded -------------------------------- IVe-10 1,770 D1b PhC3 Penn shaly silt loam, 8 to 15 percent slopes, severely eroded ---------------------------------------------- VIe-3 1,288 Dlb PnA2 Penn silt loam, 0 to 3 percent slopes, moderately eroded ---------------------------------------------- IIs-11 1,174 Cla PnB2 Penn silt loam, 3 to 8 percent slopes, moderately eroded ---------------------------------------------- IIe-10 10,209 Cla PnC2 Penn silt loam, 8 to 15 percent slopes, moderately eroded ---------------------------------------------- IIIe-10 2,576 Clb PnC3 Penn silt loam, 8 to 15 percent slopes, severely eroded ---------------------------------------------- IVe-10 443 Clb PoD Penn soils, 15 to 25 percent slopes -------------------- VIe-3 860 Cle PsB2 Penn-Steinsburg loams, 3 to 8 percent slopes, moderately eroded --------------------------------- IIe-10 612 Cla PsC3 Penn-Steinsburg loams, 8 to 15 percent slopes, severely eroded ------------------------------------ IVe-10 220 Clb RaA Raritan silt loam, 0 to 3 percent slopes ---------------- IIIw-1 417 E2a RaB Raritan silt loam, 3 to 8 percent slopes------------------ IIIw-1 302 E2a Ro Rowland silt loam -------------------------------------IIw-7 1,359 C1 StB2 Steinsburg channery loam, 3 to 8 percent slopes, moderately eroded -------------------------------- IIe-10 587 Cla StD3 Steinsburg channery loam, 8 to 25 percent slopes, severely eroded ----------------------------------- VIe-3 411 Clc UrA Urbana silt loam, 0 to 3 percent slopes ---------------- IIw-2 87 E2a UrB2 Urbana silt loam, 3 to 8 percent slopes, moderately, eroded ---------------------------------------------- IIe-13 215 E2a Ws Wiltshire silt loam -------------------------------- IIw-2 122 E2a 92 HARFORD COUNTY J j i 0 M W L MAP 4 Z SYMBOL MAPPING UNIT U D Zo .03 AdA Aldino silt loamp 0 to 3 percent slope@ ---------------------- lIv-2 440 E2a AdB Aldino silt loam, 3 to 8 percent slope* ---------------------- IIe-14 5,260 E2& AdC Aldino silt loam, 8 to 15 percent slopes --------------------- Ille-14 360 E2b AaB Aldino very stony silt loam, 0 to 8 percent slopes ----------- VIs-3 1,170 Hla AV Alluvial land ------------------------------------------------ VIv-1 2,520 G2 Bak Baile silt loam, 0 to 3 percent slopes ----------------------- Vw-l 1,110 F3 B&B Baile silt loam, 3 to 8 percent slopes ----------------------- VIw_2 1,080 F3 BeA Beltsville silt loam, 0 to 2 percent slopes ------------------ IIv-8 840 E2a BeB Beltsville silt loam, 2 to.5 percent slopes ------------------ IIe-13 2,060 E2& BeC Beltsville silt loam, 5 to 10 percent slopes ----------------- IIIe-13 610 E2a BrC2 Brandywine gravelly loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- IIIC-10 500 Clb BrD3 Brandywine gravelly loam, 15 to 25 percent slopes, severely eroded ---------------------------------------------- VIe-3 570 Clc BrB3 Brandywine gravelly loam, 25 to 45 percent slopes, severely eroded ---------------------------------------------- VIIe-3 180 Cle Cc'A Cheater silt loam, 0 to 3 percent slopes ----------u ---------- 1-4 320 Bla CcB2 Cheater silt loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- Ile-4 23,765 Bla CcC2 Cheater silt loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- Me-4 5,920 Blb CgB2 Chester gravelly silt loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- Ile-4 4,330 Bla CgC2 Chester gravelly silt loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- IIIe-4 3,220 Blb CgD2 Cheater gravelly silt loam, 15 to 25 percent slopes, moderately eroded -------------------------------------------- lVe-3 610 Blc ChB2 Chillum silt loam, 2 to 5 percent slopes, moderately eroded -------------------------------------------- IIa-7 1,670 B2a CkC2 Chillum-Neshaminy silt loame, 5 to 10 percent slopes, moderately eroded -------------------------------------------- IlIe-7 630 B2a *CrE Chrome shannery silty clay loam, 15 to 45 percent slopes ----- VII&-32 340 Cle Cu Codorus silt loam -------------------------------------------- IIw-7 7,170 G1 Cv Comus silt loam ---------------------------------------------- 1-6 890 Gl Cx Cut and fill land -------------------------------------------- ---- 680 Me Dc.A Delanco silt loam, 0 to 3 percent slopes --------------------- IIw-1 480 E3a DcB Delanco silt loam, 3 to 8 percent slopes --------------------- Ile-16 2,140 EU EhB2 Elioak silt-loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- He-4 1,840 Bla EhC2 Elioak silt loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- IIIe-4 570 Blb .En Elkton silt loam --------------------------------------------- Mw-9 740 F3 EsA Elsinboro loam, 0 to 2 percent slopes ------------------------ 1-4 400 Bla EsB2 Elainboro loam, 2 to 5 percent slopes, moderately eroded ----- IIe-4 1,420 Bla EsC2 Elsinboro loam, 5 to 10 percent slopes, moderately eroded -------------------------------------------- IIIe-4 950 Bla EvC Evesboro loamy sand, 5 to 15 percent slopes ------------------ VII*-l 100 Bla ?a Fallaington loam --------------------------------------------- Mv-7 190 F2 GcB2 Glenelg loam, 3 to 8 percent slopes, moderately eroded ------- He-4 13,610 Bla GcC2 GlenelS loam, 8 to 15 percent slopes, moderately eroded ------ IIIe-4 14,490 Blb GcC3 Glenelg loam, 8 to 15 percent slopes, severely eroded -------- IVe-3 1,220 Blb GcD2 Glenelg loam, 15 to 25 percent slopes, moderately eroded ----- IVe-3 2,850 Ble 'GcD3 Glenelg'loam, 15 to 25 percent slopes, severely eroded ------- VIe-2 950 Blc GgB2 Glenelg gravelly loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- IIe-4 2,200 Bla GgC2 Glenelg gravelly loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- 111e-4 5,880 Blb GgC3 Glenelg gravelly loam, 8 to 15 percent slopes, severely eroded ---------------------------------------------- IVe-3 590 Blb 108 Harford Co. J j _j Fa 0 6) it L I( t j MAP 4( Z u SYMBOL MAPPING UNIT U 3 V) 49 zwo GSD2 Glenelg gravelly loam, 15 to 25 percent slopes, moderately eroded -------------------------------------------- Ve-3 2,960 Blc GaD3 Glenelg gravelly loam, 15 to 25 percent slopes, severely eroded ---------------------------------------------- VIe-2 1,290 Blc GnA Glenville silt loam, 0 to 3 percent slopes ------------------- IIw-1 2,200 E2a GnB Glenville silt loam, 3 to 8 percent slopes ------------------- lIe-16 8,170 E2& Hb Hatboro silt loam -------------------------------------------- II1w-7 4,000 G2 JPB Joppa gravelly sandy loam, 2 to 5 percent slopes ------------- IIs-4 450 Ala ..Jpc Joppa gravelly sandy loam, 5 to 10 percent slopes ------------ IIle-33 630 Ala KeB Kelly silt loam, 3 to 8 percent slopes ----------------------- IVw-3 1,110 F3 KeC2 Kelly silt loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- 1%47-3 350 F3 KfD Kelly very stony silt loam, 3 to 25 percent slopes ----------- VI18-4 320 Hlc KpA Keyport silt loam, 0 to 2 percent slopes --------------------- lIw-8 280 E2& .KpB Keyport silt loam, 2 to 5 percent slopes --------------------- Ile-13 1,380 E2& KrA Kinkora silt loam, 0 to 3 percent slope's --------------------- VW-1 210 F3 KrB Kinkora silt loam, 3 to 8 percent slopes --------------------- VIw-2 170 F3 LeB2 Legore silt loam, 3 to 8 percent slopes, moderately eroded ------------------------------------------------------- Ile-10 1,010 Bla LeC2 Legore silt loam, 8 to 15 percent slopes, moderately eroded ------------------------------------------------------- Ille-10 1,110 Blb LeD2 Legore silt loam, 15 to 25 percent slopes, moderately eroded --------------------------------------------- We-10 1,690 BIc LeE Legore silt loam,'25 to 45 percent slopes -------------------- VIe-3 690 Blc LfC Legore very stony silt loam, 0 to 15 percent slopes ---------- VI*-3 310 Hlb LfD Legore very stony silt loam, 15 to 25 percent slopes --------- VI9-3 650 Hlc LfE Legore very stony silt loam, 25 to 45 percent slopes --------- VI18-3 680 Hlc L&C3 Legore silty clay loam, 8 to 15 percent slopes, severely eroded ---------------------------------------------- Ve-10 990 Blb LSD3 Legore silty clay loam, 15 to 25 percent slopes,- severely eroded ---------------------------------------------- VIe-3 1,110 BIC Lr Leonardtown silt loam ---------------------------------------- IVW_3 440 F3 LyB Loamy and clayey land, 0 to 5 percent slopes ----------------- IIIe-42 870 B3 LyD Loamy and clayey land, 5 to 15 percent slopes ---------------- Vle-2 1,660 B3 LyE Loamy and clayey land, 15 to 30 percent slopes --------------- Vl1e-2 220 B3 KbB2 Manor loam, 3 to 8 percent slopes, moderately eroded --------- Ile-25 4,190 Bla MbC2 Manor-loam, 8 to 15 percent slopes, moderately eroded -------- IIle-25 4,820 Blb MbC3 Manor loam, 8 to 15 percent slopes, severely eroded ---------- IVe-25 1,340 Blb MbD2 Manor loam, 15 to 25 percent slopes, moderately eroded ------- IVe-25 5,320 Blc MbD3 Manor loam, 15 to 25 percent slopes, severely eroded --------- VIe-3 3,230 Blc McB2 Manor channery loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- IIe-25 1,330 Bla McC2 Manor channery loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- lIle-25 5,090 Blb McC3 Manor channery loam, 8 to 15 percent slopes, severely eroded ---------------------------------------------- IVe-25 710 Blb McD2 Manor channery loam, 15 to 25 percent slopes, moderately eroded -------------------------------------------- IVe-25 5,310 Blc McD3 Manor channery loam, 15 to 25 percent slopes, severely eroded ---------------------------------------------- VIO-3 3,550 Blc WE Manor very stony loam, 25 to 45 percent slopes --------------- VIIS-3 750 Hlc MfE Manor soils, 25 to 45 percent slopes ------------------------- Vle-3 7,530 Blc MgC Manor and GleneIg very stony loams, 3 to 15 percent slopes ------------------------------------------------------- VIS-3 1,500 Hlb MSD Manor and Glenelg very stony loame, 15 to 25 percent slopes ------------------------------------------------------- V16-3 1,600 Hlc Matapeake silt loam, 0 to 2 percent slopes ------------------- 1-4 280 Bla MkB Matapeake silt loam, 2 to 5 percent slopes ------------------- Ile-4 730 Bla MIA Mattapex silt loam, 0 to 2 percent slopes -------------------- IIw-1 870 E3a M1B Mattapex silt loam, 2 to 5 percent slopes -------------------- IIe-16 1,250 EU 109 Harford Co. J j 4 0 M x L L I MAP ( z >- u SYMBOL MAPPING UNIT U 3 0 4( z MsA Montalto silt loam, 0 to 3 percent slopes -------------------- 1-4 300 B2a MsB2 Montalto silt loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- He-4 6,960 B2a MsC2 Montalto silt loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- IIIe-4 1,690 B2b NeA Neshaminy silt loam, 0 to 3 percent slopes ------------------- 1-4 370 Bla NeB2 Neshaminy silt loam, 3 to 8 percent slopes, moderately eroded -------------------------------------------- He-4 7,940 Bla NeC2 Neshaminy silt loam, 8 to 15 percent slopes, moderately eroded -------------------------------------------- IIIe-.4 3,430 Blb NeC Neshaminy and Montalto very stony'silt loams, 0 to 15 percent slopes --------------------------------------- VIS-3 5,190 Hlb NsD Neshaminy and Montalto very stony silt loams, 15 to 25 percent slopes -------------------------------------- VIS-3 1,280 Hlc NsE Neshaminy and Montalto very stony silt loam*, 25 to 45 percent slopes --------------------------------------- VIIS-3 630 Hlc Ot Othello silt loam -------------------------------------------- IIIw-7 410 F3 Sa Sand and gravel pits ----------------------------------------- VIIIS-4 570 --- ShB2 Sassafras sandy loam, 2 to 5 percent slopes, moderately eroded -------------------------------------------- Ile-5 360 Bla ShC2 Sassafras sandy loam, 5 to 10 percent slopes, moderately eroded -------------------------------------------- IIIe-5 350 Bla S1132 Sassafras loam, 2 to 5 percent slopes, moderately eroded -------------------------------------------- IIe-4 440 Bla SIC2 Sassafras loam, 5 to 10 percent slopes, moderately eroded -------------------------------------------- IIIe-4 410 Bla SaD Sassafras and Joppa soils, 10 to 15 percent slopes ----------- IVe-5 330 Blb 5sE Sassafras and Joppa soils, 15 to 30 percent slopes ----------- Vle-2 410 Blc St Stony land, steep -------------------------------------------- VIIIG-l 1,020 Hlc Sw Swamp -------------------------------------------------------- VlIw-1 140 G3 TM Tidal marsh -------------------------------------------------- VII1w-l 1,030 G3 WaA Watchung silt loam, 0 to 3 percent elope, -------------------- Vw-l 1,1 90 F3 YaB Watchung silt loam, 3 to 8 percent slopes -------------------- VIw-2 2,200 F3 WcB Watchung very stony silt loam, 0 to 8 percent slopes --------- VIIs-4 2,870 Hla WhB Whiteford silt loam, 3 to 8 percent slopes ------------------- He-4 710 Bla WhC2 Whiteford silt loam, I to 11 percent slopes, moderately eroded ------------------------------------- ------- IIIe-4 500 Blb WoB Woodstown loam, 0 to 5 percent slopes ------------------------ He-16 240 Ela Total Area Mapped 242,175 Note: Unmapped area (U. S. Military Res.) 44,545 110 HOWARD COUNTY MAP SYMBOL MAPPING UNIT SYMBOL MAPPING UNIT AjB2 Aldino silt loam, 3 to 8 percent slopes, moderately eroded -------- IIe-13 213 E2a AdC2 Aldino silt loam, 8 to 15 percent slopes, moderately eroded ---------- IIIe-13 98 E2b AgB2 Aura gravelly loam, 1 to 5 percent slopes, moderately eroded---------- IIe-7 170 B2a AgC2 Aura gravelly loam, 5 to 10 percent slopes, moderately eroded-- ------ IIIe-7 241 B2a AgE3 Aura gravelly loam, 10 to 30 percent slopes, severely eroded---------- VIIe-2 196 B2c Ba Baile silt loam ------------------------------------------------ Vw-1 3,318 F3 BeA Beltsville silt loam, 0 to 1 percent slopes ------------------------- IIW-8 108 E2a BeB2 Beltsville silt loam, 1 to 5 percent slopes, moderately eroded ------------------------------------------------------- IIe-13 1,383 E2a BeC2 Beltsville-silt loamy 5 to 10 percent slopes, moderately eroded ------------------------------------------------------- IIIe-13 557 E2a BeC3 Beltsville silt loam, 5 to 10 percent slopes, severely eroded-- IVe-9 465 E2a BeD2 Beltsville silt loam, 10 to 15 percent slopes, moderately eroded----------------------------------------------- IVe-9 327 E2b BrB2 Brandywine loam, 3 to 8 percent slopes, moderately eroded-------- IIe-10 883 Cla BrC2 Brandywine loam, 8 to 15 percent slopes, moderately eroded------- IIIE-10 898 Clb BrC3 Brandywine loam, 8 to 15 percent slopes, severely eroded --------- IVe-10 712 Clb BrD2 Brandywine loam, 15 to 25 percent slopes, moderately eroded ------ IVe-10 420 C1C BrD3 Brandywine loam, 15 to 25 percent slopes, severely eroded ------ VIe-3 799 Clc BrF Brandywine loam, 25 to 60 percent slopes ----------------------- 1,052 C1c North aspect ---------------------------------------------- VIIE-3 South aspect ---------------------------------------------- VIIe-3 BwD Brandywine very stony loam,3 to 25 percent slopes ---------------- VIs-3 142 Hlc CgB2 Chester gravelly silt loam, 3 to 8 percent slopes, moderately----- IIe-4 --------- 3.536 Bla eroded------------------------------------------------------------ IIe-4 3.536 Bla CgC2 Chester gravelly silt loam, 3 to 15 percent slopes, moderately---- eroded------------------------------------------------------------ IIIe-4 2,530 Blb ChA Chester silt loam, 0 to 3 percent slopes ----------------------- I-4 2,409 BLa ChB2 Chester silt loam, 3 to 8 percent slopes, moderately eroded-------- IIe-4 14,577 Bla ChC2 Chester silt loam, 8 to 15 percent slopes, moderately eroded ------ IIIe-4 2,875 Blb ChC3 Chester silt loam, 8 to 15 percent slopes, severely eroded -------- IVe-3 719 Blb ChD2 Chester silt loam, 15 to 25 percent slopes, moderately eroded------ IVe-3 802 Blc C103 Chillum gravelly loam, 5 to 10 percent slopes, severely eroded ------------------------------------------------------- IVe-7 447 B2a CID2 Chillum gravelly loam, 10 to 15 percent slopes, moderately eroded -------------------------------------------------------- IVe-7 304 B2b CIE2 Chillum gravelly loam, 15 to 30 percent slopes, moderately eroded ------------------------------------------------------- Vle-2 140 B2c CmB2 Chillum silt loam, 1 to 5 percent slopes, moderately eroded ------ IIs-7 882 B2a CmC2 Chillum silt loam, 5 to 10 percent slopes, moderately eroded IIIe-7 265 B2a CnB2 Chillum Fairfax loams, 1 to 5 percent slopes, moderately eroded ------------------------------------------------------- IIs-7 323 B2a CnD3 Chillum-Fairfax loams, 5 to 15 percent slopes, severely eroded ------------------------------------------------------- Vle-2 401 B2b Co Codorus silt loam ---------------------------------------------- IIw-7 3,871 G1 Cs Comus silt loam ------------------------------------------------ I-6 697 G1 Cub Comus silt loam, local alluvium, 3 to 8 percent slopes --------- IIe-6 1,199 G1 Elioak silt loam, 0 to 3 percent slopes----------------------- I-4 401 Bla EkB2 Elioak silt loam, 3 to 8 percent slopes, moderately eroded---------- IIe-4 2,779 Bla EkC2 Elioak silt loam, 8 to 15 percent slopes, moderately eroded---------- IIIe-4 987 Blb EkD2 Elioak silt loam, 15 to 25 percent slopes, moderately eroded ------ IVe-3 134 Blc Howard Co. J J i 0 a jr L MAP SYMBOL MAPPING UNIT z >. U U 3 0 Z 0 ElC3 Elioak silty clay loam, 8 to 15 percent slopes, severely eroded ------------------------------------------------------- IVe-3 411 Blb EID3 Elioak silty clay loam, 15 to 25 percent slopes, severely eroded ------------------------------------------------------- VIe-2 126 Blc Em Elkton silt loam ----------------------------------------------- Jjjw_9 94 F3 EnA Elsinboro loam, 0 to 3 percent slopes -------------------------- I _JA 136 Bla EnB2 Elsinboro loam, 3 to 8 percent slopes, moderately eroded ------- IIe-4 356 Bla -EnC2 Elsinboro loam, 8 to 15 percent slopes, moderately eroded ------ IIIe-4 156 Blb 'EvB Evesboro loamy sand, 1 to 5 percent slopes --------------------- JVs-l 146 Ala EvC Evesboro loamy sand, 5 to 15 percent slopes -------------------- VIIS-1 258 Alb .F9 Fallsington loam ----------------------------------------------- Mw-7. 356 F2 GIA Glenelg loam, 0 to 3 percent slopes ---------------------------- 1-4 508 bla GlB2 Glenelg loam, 3 to 8 percent slopes, moderately eroded --------- IIer4 15.616 Bla GIC2 Glenelg loam, 8 to 15 percent slopes, moderately eroded -------- IlIe-4 7.b35 Blb GIC3 Glenelg loam, 8 to 15 percent slopes, severely eroded ---------- Ve-3 2.777 Blb GlD2 Glenelg loam, 15 to 25 percent slopes, moderately eroded ------- IVe-3 1,290 Blc -GlD3 Glenelg loam, 15 to 25 percent slopes, severely eroded --------- VIe-2 92b Blc GnA Glenville silt loam, 0 to , percent slopes --------------------- JJ'4_6 1 '124 E2a, GnB2 Glenville silt loam, 3 to 8 percent slopes, moderately eroded-- IIe-13 5,266 E2a, GnC2 Glenville silt loam, 8 to 15 percent slopes, moderately eroded ------------------------------------------------------- Me-13 146 E2b :G,., Gravel pits and quarries --------------------------------------- VIII S-1 129 BP Ha Hatboro silt loam ---------------------------------------------- IIIW-7 3,381 G2 IuB Iuka loam, local alluvium, I to 5 percent slopes --------------- IIe-16 692 Gl KcE3 Kelly clay loam, 15 to 30 percent slopes, severely eroded ------ VIIe-2 131 F3 KeB2 Kelly silt loam, 3 to 8 percent slopes, moderately eroded ------ IVW-3 386 F3 KeC2 Kelly silt loam, 8 to 15 percent slopes, moderately eroded ----- IVw-3 145 F3 KhC2 Keyport silt loam, 3 to 10 percent slopes, moderately eroded --- 1110-13 124 Z2a Kn Kinkora silt loam ---------------------------------------------- VW-1 144 F3 LeB2 Legore silt loam, 3 to 8 percent slopes, moderately eroded ----- IIe-10 380 Bla LeC2 Legore silt loam, 8 to 15 percent slopes, moderately eroded ---- Ille-10 143 B1b I-gC3 Legore silty clay loam, 8 to 15 percent slopes, severely eroded ------------------------------------------------------- IVe-10 150 Blb Ll Leonardtovn silt loam ------------------------------------------ IVW-3 480 F3 LnB2 Linganore channery loam, 3 to 8 percent slopes, moderately eroded ------------------------------------------------------- 1118-10 212 Cla @nC2 Linganore channery loam, 8 to 15 percent slopes, moderately eroded ------------------------------------------------------- M-10 391 Clb LnD2 Linganore channery loam, 15 to 25 percent slopes, moderately eroded ------------------------------------------------------- VIe-3 148 Clc L .oE Linganore channery silt loam, 25 to 45 percent slopes ---------- -- 142 Clc North aspect ---------------------------------------------- VIIe-3 South aspect ---------------------------------------------- Me-3 Md Made land ------------------------------------------------------ -- h97 Ma MgB2 Manor gravelly loam, Ito 8 percent slopes, moderately eroded-- Ile-25 1,863 Bla MgC2 Manor gravelly loam, 8 to 15 percent slopes, moderately eroded ------------------------------------------------------- IIIe-25 3,137 Blb. MgC3 Ma nor gravelly loam, 8 to 15 percent slopes, severely eroded --- M-25 913 Blb YlA Manor loam, 0 to 3 percent slopes ------------------------------ IIs-25 284 Bla MIB2 Manor loam, 3 to 8 percent slopes, moderately eroded ----------- IIe-25 4,902 Bla MlC2 Manor loam, 8 to 15 percent slopes, moderately eroded ---------- Me-25 4,967 112b MIC3 Manor loam, 8 to 15 percent slopes, severely eroded ------------ IVe-25 4,019 B2b MID2 Manor loam, 15 to 25 percent slopes, moderately eroded --------- IVS-25 3,927 BIc ,MlD3 Manor loam, 15 to 25 percent slopes, severely eroded ----------- V18-3 5,005 Blc MlE Manor loam, 25 to 45 percent slopes ---------------------------- VXIO-3 3,105 Ble MaD Manor very stony loam, 3 to 25 percent slopes ------------------ VIS-3 1,239 H1C ka Manor very stony loam, 25 to 60 percent slopes ----------------- VIIS-3 1,759 Hie Mo Mixed alluvial land --------------------------------------------- VIW-l 416 G2 jMpB2 Montalto silt loam, 3 to 8 percent slopes,-moderately eroded --- Ile-4 628 B2a MpC2 Montalto silt loam, 8 to 15 percent slopes, moderately eroded-- Me-4 193 B2& 112 Howard Co. MAP SYMBOL MAPPING UNIT Montalto silty clay loam, 8 to 15 percent slopes, severely eroded ---------------------------------------------------------- IVe-3 123 B2b Montalto and Relay soils, 15 to 45 percent slopes -------------- VIe-2 630 B2c Montalto and Relay very stony silt loams, 3 to 25 percent slopes -------------------------------------------------------- VIs-3 721 H1c Montalto and Relay very stony silt loams, 25 to 60 percent slopes--------------------------------------------------------- VIIs-3 590 H1c Mt. Airy channery loam, to percent slopes, moderately eroded------------------------------------------------------------------ IIIe-10 3,084 C1a Mt. Airy channery loam, to percent slopes, moderately eroded ---------------------------------------------------------------- IVe-10 4,590 C1b Mt. Airy channery loam, to percent slopes, severely eroded ---------------------------------------------------------------- VIe-3 1,706 C1b Mt. Airy channery loam, to percent slopes, moderately eroded --------------------------------------------------------------------- VIe-3 3,831 C1c Mt. Airy channery loam, 25 to 45 percent slopes------------------------------ --- 1,747 C1c North aspect------------- VIIe-3 South aspect-------------- VIIe-3 Neshaminy silt loam, 3 to 8 percent slopes, moderately eroded ---------------- IIe-4 957 B1a Neshaminy silt loam, 8 to 15 percent slopes, moderately eroded --------------- IIIe-4 595 B1b Neshaminy silty clay loam, 15 to 25 percent slopes, severely eroded ------------------------------------------------------------------ VIe-2 224 B1c Relay silt loam, 3 to 15 percent slopes, mderately eroded--------------------- IIIe-10 209 C1b Rumford loamy sand, 1 to 5 percent slopes, moderately eroded------------------ IIs-4 82 A1a Rumford loamy sand, 5 to 10 percent slopes, moderately eroded---------------- IIIe-33 127 A1a Rumford loamy sand 10 to 15 percent slopes, moderately ---------------------- IVe-5 90 A1b eroded Sandy and clayey land, gently sloping------------------------------- IIIe-41 360 B3 Sandy and clayey land, moderately sloping-------------------------- VIe-2 795 B3 Sandy and clayey land, moderately steep----------------------------- VIIe-2 338 B3 Sassafras gravelly sandy loam, 1 to 5 percent slopes, moderately eroded---------------------------------------------- IIe-5 482 B1a Sassafras gravelly sandy loam, 5 to 10 percent slopes, moderately eroded------------------------------------------------ IIIe-5 723 B1a Sassafras gravelly sandy loam, 10 to 15 percent slopes, moderately eroded------------------------------------------------- IVe-5 295 B1b Sassafras loam, 1 to 5 percent slopes, moderately eroded------------- IIe-4 532 B1a Sassafras loam, 5 to 10 percent slopes, moderately eroded------------- IIIe-4 432 B1a Sassafras soils, 15 to 25 percent slopes------------------------------ IVe-3 222 B1b Stony land-------------------------------------------------------------- VIe-2 348 B1c Sunnyside fine sandy loam, 1 to 5 percent slopes, moderately eroded------------------------------------------------------------ VIIIs-1 347 H1 Sunnyside fine sandy loam, 5 to 15 percent slopes, moderately eroded------------------------------------------------------------- IVe-5 62 B1a Watchung silt loam, 0 to 3 percent slopes------------------------------ Vw-1 341 F3 Watchung silt loam, 3 to 8 percent slopes------------------------------ VIw-2 214 F3 Woodstown sandy loam, 1 to 5 percent slopes, moderately eroded------------------------------------------------------------- IIe-36 190 E1 TOTAL 160,640 113 I I I I APPMOIX 9 I Maps for Detailing Site Conditions I I I I I I I I I I I I 'A E-1 Maps for Detailing Existing Site Conditions in an Urban Retrofit Assessment Map Type Use(s) Scale(s) Source(s) Aerial Photography Land Use Types, Vegetation, >=1'=2000 Private Aerial Survey Companies Parks & Open Space, Erosion Local Government Contract Surveys Department of State Planning Flood Plain Topography, landforms,slopes, >=1'=2000 Local Watershed Surveys Receiving Waters State Watershed Surveys S.C.S. Napping Surveys Geologic Landforms, Soils, Subsurface >=1'=2000 Maryland Geologic Survey Conditions US Geologic Survey Highway Land Uses, Boundaries, Potential >=1'=2000 Maryland State Highway Adain Problem Areas Local Highway Depts. Land Use Land Uses, Parks & Open Space >=1'=2000 Local Planning & Zoning Depts. Natural Resources Vegetation, Parks, Open Space >=1'=1mile State Forest & Park Service Maryland Geologic Survey Local Government Depts. Park & Open Space Land Uses, Parks, Open Space >=1'=2000 Department of State Planning Local Parks & Recreation Depts. State Dept. of Natural Resources Flat Land Uses >=1'=2000 Local Public Works Depts. Recreation Land Uses, Parks, Open Space >=1'=2000 Local Parks & Recreation Depts. Department of State Planning Soils Soil Physical I Chemical >=1'= 1320 SCS Soil Surveys of Local Characteristics, Slope, Hydro- Jurisdictions logic conditions, Vegetation Storm Drain Systems Storm Drainage Patterns, Land >=1'=500 Subdivision Plans (Public Works) (Plan I Profile) Does, Drainage Boundaries Public Works Dept. Projects Utilities Depts. Projects Local & State Highway Dept. Projects Tax Land Uses, Public Lands, Boun- >=1'=660 Local Tax Assessors' Offices daries Topographic Topography, Slopes, Drainage >=1'=2000 U.S. Geological Survey Boundaries, Receiving Waters, Maryland Geological Survey Land Uses/Covers Local Photogrammetric Surveys Site Survey Maps E-2 Maps for Detailing Existing Site Conditions in an Urban Retrofit Assessment (Continued) Map Type Use(s) Scale(s) Source(s) Utilities Land Uses/Covers, Imperviousness >= 1'=2000 Balto. Gas & Electric Co. Calculations Local Public Works Depts. Vegetation Land Covers, Imperviousness >=1'=2000 State Forest Service Calculations, Potential Areas Maryland Geological Survey for Management Practices U.S. Geological Survey Habitat Assessment Studies Wildlife Impact Assessment, Natural Areas, >=1'=1 mile State Dept. Natural Resources Parks, Open Space Local Habitat Assessments U.S. fish & Wildlife Service E- 3 I I I I APPENDIX F I S umm aries of Urban Retrofit Management Practices I I I I I I I I I I I I I I F-1 Summaries of Urban Retrofit Management Practices The following section includes brief summary descriptions of water quality management practices (control measures) that are potential candidates for application in existing urban areas. These summaries should be supported by information about specific management practices in the "Urban Water Quality Management Practice Resource Directory" in Part IV of the Guide. Remember that most of these practices have been designed for and used in newly developed areas - not as retrofit controls. Some controls may require modifying prior to use in retrofitting or may not be suitable as retrofit controls. INFILTRATION Dry Well The purpose of a dry well is to capture and store runoff from rooftop areas of less than one acre surface area for infiltration into surrounding soil. A dry well consists of a small excavated pit backfilled with aggregrate. The dry well is similar in design to the infiltration trench but has a smaller surface area but a depth ranging from 3 to 12 feet. Another difference between the dry well and the trench is that the dry well accepts inflow through an inflow pipeand surface infiltration. The trench can only accept inflow through the surface or inlet flow. The considerations for use of a dry well include: minimum construction depth, maximum allowable storage time, surface area requirements for a specified level of control, and the infiltration rate of the soil textural classes (>= 0.27 in/hr.). All infiltration devices are subject to clogging by sediment, oil, grease, grit, and other debris and should be designed so that runoff entering them is reduced. The bottom of the dry well must be at least 2 to 4 feet above the seasonally high groundwater table as well as bedrock. The dry well must also be located at least 100 feet horizontally form any water supply well. Dry wells can be used to drain roof runoff from residential, commercial, industrial, and institutional buildings. Trench The purpose of an infiltration trench is capture a portion or all of the runoff from relatively small drainage areas for infiltration into the soil. F-2 An infiltratio n trench consists of a shallow excavated trench, generally 2 to 10 feet in depth, backfilled with a coarse stone aggregate, allowing for temporary storage of storm runoff in the voids between the aggregrate material. The trench is designed to allow slow infiltration of the stored water into the surrounding ground. Unlike the dry well which is covered with soil and vegetation and a subsurface inlet, the surface of the trench consists of stone, gabion, sand, or a grass covered area with a surface inlet. The trench is designed using the same general reqirements as the dry well. In addition, the trench should be designed to minimize the surface area by making it as deep as possible with three feet a minimum. All infiltration systems are subject to clogging by sediment, grease, oil , grit, and debris. The trench should be designed and constructed to include grass filter strips for filtering the runoff prior to it entering the trench. Three variants of the infiltration trench have been introduced (MWCOG, July 1987). These include: (1) the complete exfiltration system in which all water entering the trench infiltrates into surrounding soil, (2) the partial exfiltration trench in which a perforated underdrain in the trench bottom with a riser to allow only large storms to overflow from the trench, and (3) the water quality exfiltration system in which the trench is designed to receive only the first flush of runoff. The infiltration trench can be used in residential lots, commercial areas, parking lots, and open space areas. A trench can also be installed under a swale to increase the storage of the infiltration system. The water quality exfiltration trench design, because it captures only small runoff events or portions of larger events, is considerably flexible in its placement within the urban area. Basin The purpose of the infiltration basin is to intercept runoff after preliminary concentration and infiltrate the water through the basin bed or sides. An infiltration basin is a water impoundment made by constructing a dam or an embankment or by excavating a pit or a dugout in or down to relatively permeable soils. A typical basin will range in depth from 3 to 12 feet. Both bedrock and seasonally high groundwater table should be located 2 to 4 feet below the bottom of the basin. The design will be based on the permeability or final infiltration rate of the soil types surrounding the basin, but a basin cannot be built on soils with an infiltration rate ( 0.27 inches/hour. All infiltration systems can become clogged and the basin will require placement of runoff filtering devices such as vegetative filters, sediment traps, and grease traps upslope of the basin entrance. F-3 Four design variants have been proposed by MWCOG (July 1987). These include: (1) the full infiltration basin, (2) combined infiltration/detention basin, side-by-side basin, and the (4) the off-line infiltration basin. An infiltration basin can be used in the same general way as a detention basin. The infiltration basin is suitable for drainage areas of 5 to 50 acres. It can be constructed jointly with a detention basin by raising an outlet pipe. Porous Pavement The purpose of porous paving is to capture rainfall at the source, infiltrating and temporarily storing it for later drainage. The use of porous paving increases infiltration, reduces flood peaks, and provides an opportunity for pollutant removal. Porous paving or porous asphalt refers to a porous asphaltic paving material and a high void aggregate base that allows for rapid infiltration and temporary storage of runoff and rain falling on paved surfaces. This type of paving is an applicable substitute for convential asphalt pavement on parking areas and low-traffic volume roads provided that the grades, subsoil drainage characteristics, and groundwater table conditions are suitable for use. Generally, the grades must be very gentle to flat, the subsoil must be at least moderately permeable (f >= 0.27 in/hr), and the depth to the water table or bedrock must be 2 to 4 feet. Three alternative designs have been proposed for porous pavement (MWCOG, July 1987). The first is a full exfiltration system allowing complete infiltration into the subsoil. The second design is partial exfiltration which only infiltrates a part of the runoff and collects the remaining flow in underdrains. The third alternative design is a water quality exfiltration system which has a stone reservoir sized to handle only the "first flush" of a runoff event. The application of porous paving includes: parking lots (especially fringe and overflow parking); parking aprons, taxiways, and shoulders at airports; emergency stopping and parking lanes and vehicle cross-overs on divided highways; low- traffic volume roads; rooftop runoff; and runoff from adjacent paved areas. Some advantages include the need for less land, reduction or elimination of curbs and gutters, downstream conveyance systems, preservation of the natural water balance at the site, and a safer driving surface with better skid resistance. The major disadvantage of porous paving is that if it F-4 becomes clogged, it losses its permeability and is difficult and costly to rehabilitate. Modular Pavina The purpose of modular paving is to allow infiltration of rainfall-runoff on areas that are normally paved with impermeable materials. Modular paving consists of precast concrete lattice blocks or bricks placed on soils that are well or moderately well drained to allow partial infiltration while providing a structurally sound surface for support. The modular paving is generally unsuitable for sloping sites unless used to pave level terraces, Modular paving has at least four advantages. First, lattice concrete blocks permit the establishment of grass, reducing the visual impact of large areas of pavement. Second, because these pavers are all small units laid on a non-rigid base, small sections can be lifted for access to underground utilities or repairs. Third, a variety of patterns can be used. Last, these pavements are flexible and can withstand minor movements without cracking. Disadvantages include: use of skilled labor required to lay modular paving, possible poor permeability on moderately well drained soils unless deep sub-base is laid, a poor walking surface created by lattice blocks and brick with wide joints, and weed growth in joints of some materials requiring maintenance. INFILTRATION/FILTRATION/FI#OW ATTENUATION Grassed Swale The purpose of a vegetated or grassed swale is to serve as natural drainage ways for stormwater runoff. A swale slows down the concentrated runoff velocity and filters out some particulate pollutants. Grassed swales are typically applied in residential developments and highway medians as an alternative to curb and gutter drainage systems. A swale will remove some particulate pollutants by filtering action but are not generally capable of removing soluble pollutants. A swale can help to control peak discharge in two ways: (1) reducing runoff velocity and increasing time of concentration and (2) infiltrating a portion of the runoff volume. To improve the effectiveness of a swale, several supplemental devices can be used. on slopes less than 5%, check F-5 dams can be installed across swales to further retard the water. Infiltration trenches can also be located under swales to improve infiltration. Grass Filter Strip The purpose of a grassed (vegetated filter strip) is to intercept sheet runoff flow to prevent concentration of runoff, lower runoff velocity, slightly reduce both runoff volume and watershed imperviousness, and contribute to groundwater recharge. Filter strips are similar to grassed swales except rather than collecting concentrated flow, they collect only sheet flow. Since runoff has a strong tendency to concentrate into channels by short circuiting, a grass filter strip must be designed to distribute flow evenly. To work properly, a filter strip must have a level spreading device; dense vegetation with a mix of erosion resistant plant species that bind the soil; a uniform, even, and relatively low slope; and a length as long as the contributing area. Filter strips have several advantages. They are relatively inexpensive to establish and have low maintenance requirements. A creatively landscaped filter strip provides a community amenity, wildlife habitat, screening, and stream protection. One use in a system of management practices is the application of a grass filter strip to protect surface infiltration trenches from clogging by sediment. TRAPPING Water Quality Inlet The purpose of a water quality inlet (also called an oil/grit separator) is to remove sediment and hydrocarbon loadings (oil and grease) from paved areas before discharging to a storm drain system or infiltration device. Two designs for water quality inlets have been issued each by Montgomery County and the City of Rockville. The Montgomery County inlet is a long rectangular concrete box connected to a storm drain with three chambers. Runoff flows through each of the three chambers in series with the total design separating out sediment, grit and oil before exiting through the storm drain pipe. The first chamber contains a permanent pool three or four feet deep and is used for gravity settling of grit, sediments, leaves, and floatable debris. It is connected to the second chamber by a pair of well-screened six inch holes. The second chamber holds a permanent pool of water with an inverted pipe elbow leading to a third chamber. The second chamber traps oil and gas films floating on the water surface which eventually F-6 settle out into the sediments. The third chamber is a brick cradle forming the transition to the storm drain pipe. It can be designed to also hold a permanent pool for further settling or not. In the Rockville design is similar to Montgomery County in that it has also a three chamber design. However, the first and second chambers do not have permanent pools. Instead, the flow drains through a series of screened six inch holes in the floor of the chamber into and through a layer of stone aggregate, and eventually exfiltrates into the subsoil. If the weep holes clog, the device would operate in the same way as the Montgomery County design. Water quality inlets store only a small fraction of the two year design storm volume. Pollutant removal effectiveness of these devices has never been monitored. However, the brief retention time and volume of the devices would probably limit the removal of solids to moderate levels. Fine grained material removals will probably be even more limited. Soluble pollutants will probably pass through the device. The water quality design will typically serve parking lots one acre or less in size and well suited for areas receiving larger volumes of vehicular traffic or large petroleum inputs (i.e. gasoline service stations, loading areas, etc.). Routine maintenance should be performed at least twice a year. STORAGE/RELEASE Parkina Lot Storage The purpose of parking lot storage is to detain stormwater runoff during moderate storms in order to reduce peak runoff discharges to receiving waters and provide initial settling of sediment and particulate pollutants. The use of parking lots for temporary storage of runoff is most applicable in areas with few opportunities to provide for stormwater detention. The ponding depth should not not exceed six inches to avoid flooding auomobile interiors. The practice is especially appropriate for overflow parking areas and lots which are not in regular use but must not inconvience the customer and car owner. The practice has several advantages: a reduction of peak discharge, additional flood storage at low cost, will result in larger removal of sediment, and may be used in winter recreation. ice skating. Disadvantages include inconvience to users of the parking lot. possible damage to unauthorized autos, and frequent F-7 sediment and debris removal required. Dry Basin A dry basin, also called a detention basin, is designed to control peak stormwater runoff discharges for 2 and 10 year return frequency storms. As designed, the dry basin does not provide any significant pollutant removal because of the detention time and positive flow of the basin. However, if a dry basin meets certain physical requirements, it can often be modified (retrofitted) to include pollutant removal with the stormwater management objectives. One modification is the conversion of a dry basin to an extended detention basin by providing a means of detaining the water for 24 hours or more. Another modification is the installation of a shallow marsh system in the basin. A third alternative is the conversion of the dry basin to a wet pond. Extended Detention Basin The purpose of extending the detention times of dry basins and wet ponds is to provide an effective, low cost means of removing particulate pollutants and controlling increases in downstream bank erosion. Both dry basins and wet ponds can be adapted to achieve extended detention times. A two stage design is recommended for dry basins in which the top portion of the pond is designed to remain dry most of the time, and a smaller portion near the riser is regularly inundated. Methods to achieve extended detention times in dry basins and wet ponds are: Perforated Riser Enclosed in a Gravel Dry Basin Jacket Perforated Extension of Low Flow Orifice, Dry Basin Inlet Controlled Perforated Extension of Low Flow Orifice, Dry Basin Outlet Control Slotted Standpipe from Low Flow Orifice, Dry Basin, Shallow Inlet Control Marsh, Shallow Wet Pond Negatively Sloped Pipe from Riser Wet Ponds, Shallow Marshes Hooded Riser Wet Ponds F-8 By extending the stormwater detention time by 24 hours or more, as much as 90 % removal of the particulate pollutants can be removed. However, only slight removals of soluble phosphorus and nitrogen are possible. These removals can be enhanced if the area normally inundated is managed as a shallow marsh or a permanent pool. Construction costs are seldom more than 10% above those reported for dry ponds. Maintenance requirements are moderate to high, depending on the anticipation of future maintenance needs during construction. Routine maintenance includes mowing, inspections, debris and litter removal, erosion control, and nuisance control. Non-routine maintenance can include structural repairs and replacement and sediment removal. Wet Pond The purpose of a wet pond (also called a retention pond) is to achieve high removals of pollutants, provide a community aquatic resource, and provide wildlife habitat. Wet ponds are structural basins of impounded water with a permanent pool. If properly sized and maintained, wet ponds can achieve a high removal rate for pollutants including sediment, BOD, organic nutrients, and trace metals. Biological processes also remove soluble nutrients. Wet ponds must, however, be carefully planned, designed, constructed, and maintained. Because the wet pond is a multi-purpose BMP, competing objectives for use must be resolved to provide stormwater management, pollutant removal, and landscaping/habitat improvement. The best applications for wet ponds is in residential or commercial developments greater than 20 acres with a reliable source of baseflow. Positive impacts of wet ponds include: creation of local wildlife habitat, higher property values, recreation, and landscape amenities. Negative impacts include: possible upstream ans downstream habitat degradation, potential safety hazards, occassional nuisance problems, and the eventual need for sediment removal (a costly operation). NATURAL SYSTEMS Shallow Marsh System The purpose of the shallow marsh system is to use shallow vegetated marsh land created by detention of water to provide removal and treatment of stormwater runoff by biological activity and extended detention. F-9 The shallow marsh system is a collection of wetland plant species in a multiple depth water environment with sufficient baseflow to maintain a relatively constant water level. Since most wetland plant species thrive in shallow water conditions of one foot or less, most of the surface area will be at this depth. Optimal nutrient removal is achieved when the surface area is maximized - generally the marsh system being 2 - 3 percent of the total area of the contributing watershed. A shallow wetland will be heavily vegetated with only 25 % of the total area in open water of two feet or more in depth. A heavily vegetated basin should provide food and shelter to insects, birds, animals', and fish. Shallow marsh systems have several variants. A system can be constructed for a single purpose as a shallow marsh with little detention of stormwater. A shallow marsh system can be integrated into the design of a detention basin, extended detention basin, or wet pond by providing shallow benches for aquatic growth or in sediment forebays. Because little or no excavation is needed for the shallow water required in these basins, existing dry stormwater basins (detention basins) can be retrofitted with shallow marsh systems. This is possible if a baseflow passes through the basin. PHYSICAL TREATMENT Sand Filter The purpose of the filtration basin (sand filter) is to remove suspended particulate matter and the associated adsorbed chemical constituents by filtering the runoff through a sand bed. The City of Austin, Texas has developed water quality design guidelines for filtration basins (1986). The Austin guidelines require the first one-half inch of stormwater runoff to be diverted from the main flow stream by isolation baffles and a diversion weir or by alternative methods. Alternative configurations, listed by priority, are: � Separate sand filtration of first one-half inch of runoff and provide stormwater detention in separate basin. � Provide stormwater retention/detention followed by sand filtration. � Combine detention (sedimentation) and sand filtration in single basin. The filtration of stormwater runoff is based on design criteria for slow rate filters. The calculation requires the drainage area contributing runoff to the basin and the runoff depth to F-10 calculate the necessary surface area of the sand media. The maximum recommended drainage area is 50 acres for each filtration basin system. Swirl Concentrator/Helical Bend The purpose of the swirl concentrator/helical bend device is to concentrate suspended material in stormwater runoff into a small volume for removal and disposal. The swirl concentrator and the helical bend are two devices that depend on the hydraulics of flowing water to concentrate suspended solids from the main stream to a point of further treatment or disposal. The swirl concentrator operates by the swirl action of the flow entering a cylindrical chamber tangentially and travels in a vortex path of decreasing radius. The liquid-solid separation concentrates the solid matter, which leaves the chamber through a foul flow outlet in the chamber floor near the center. the concentrated liquid-solid slurry is either treated directly or stored for later treatment. Treatment occurs by connection to a sanitary sewer system for delivery to the wastewater treatment plant or alternative process. One possible method for stormwater would be use of sand bed filtration following swirl concentration. The helical bend device operates similarly to sediment depositing along curved sides in streams or rivers. The operating principle is that flow moves into a curved path in a hannel cross section with the deepest part at the inside of the curve. Solids are channeled into the trough by secondary currents and moved to the end of the bend and are removed into a storage device or routed directly to a treatment system. A smooth transition from the circular sewer storm drain pipe to the start of the bend is essential. Both of these types of units are static - operating without moving parts and require no outside source of power. Both can remove up to 50 percent of the suspended solids. Both are effective for treating separate stormwater discharges. Both devices serve a dual function - physical treatment and regulation of the flow. Plate/Tube Separator The plate/tube separator's purpose is to reduce the detention time and fall distance of pollutant particles in a settling basin - removing particles of smaller size in less time. The process invloves directing the runoff flow through either stacked plates or, more practically, inclined tubes. F-11 'A The slope of the tube contributes to self cleaning of the settled material on the bottom of the tube. Commercial units are available that consist of a lightweight plastic grid with 2in. X 2 in. passageways in cross section with a length of 24 inches, inclined with a slope of 600 to the horizontal. In use, the module is submerged to a shallow depth below the water surface. The runoff enters from the bottom, passes upward through the tubes, and exits the top. Average flow velocity through the tubes is very slow (< 0.01 fps), and larger particles settle to the tube invert. They eventually drop to the tank bottom and must be removed. Tube settlers have been used in several applications. The inclined tube concept has had some success in clarication of effluent from waste water treatment plants. It permits a higher rate of flow through the basin while maintaining good efficiency of particle removal. USEPA examined the tube settler for removing sediment from runoff at construction sites by installing the device at the downstream end of a sediment basin (July 1979). Tests revealed that when used in conjunction with the basin, particle removals of 60 - 70 percent were seen, implying that fines in the clay range were also removed. Screens The purpose of screens is the removal of floating or suspended solids from runoff. The process of particle removal for screens ranges in difficulty from little to great. Screens in various shapes and sizes are installed in the runoff flow path and removes materials larger in size than the smallest opening in the screen. Because the material remains on the screen, it must be removed periodically to maintain the efficiency of the screen. Screens have been used or tested in various runoff and combined sewer- related condtions. Perhaps the most common of these in managing stormwater runoff is the trash rack installed at the riser or spillway of a sediment or stormwater management pond. Debris barriers are commonly used-in streams where floating debris is a serious hazard due to stream instability and upstream development. USEPA has tested screens and micro- strainers to remove various sizes of particles from stormwater and combined sewer systems prior to treatment. These screens are made of stainless steel or plastic, in the form of micro- strainers, drums, and discs. operation of screens in the smaller pore opening ranges have had mixed success and normally high operation and maintenance costs. As a general rule, the difficulty and cost of removing suspended solids is inversely proportional to their size. F-12 Glossary G18-1 Glossary Analysis Area A drainage area within a priority watershed. The analysis area can be a subwatershed, creekshed, subcreekshed, or even as small as a storm drain system. Analysis Area Information Table A matrix-type table that lists the characteristics, composition, and magnitude of urban areas in the analysis area. Analysis Area Urban Retrofit Strata" The results of Step 5 of the method. Included are a combination of analyses and maps pointing out potential retrofit control measures that can be applied to the selected analysis area. Candidate Urban Retrofit Management Practice A proposed water quality management practice. The practice can be a modification to an existing or new practice. Catchment (urban) The smallest unit of drainage area in a watershed. A catchment has little or no natural stream channel with the flow patterns governed by storm drain systems. Concensus Judgment (See Delphi Technique.) Creekshed A drainage area one level smaller in size than the watershed, two or more of which make up the total watershed drainage area. Develop" Areas (Land) Land on which buildings, roads, parking lots, and other structures have been constructed for long term human habitation and activities. Delphi Technique A problem analysis and solution method developed by the Rand A Corporation. The procedures require the collection of opinions of experts. The participants are shown the median and range of the individual, independent votes about an issue and asked to reconsider the issues. After several rounds of voting, more often than not, the judgments will converge toward a single answer. Drainage Area Boundaries Imaginary lines defined by the topography of the land that divide the drainage areas. Drainage areas can be defined at Gls-2 several levels - from a watershed down to the many sub- watersheds and many more catchments within a watershed. Erosion Control The assessment of problem conditions or sources and the application of one or more control measures to prevent, reduce, or eliminate the problem. Controls are designed to address the runoff source, or sheet, rill, or gully erosion. Event Mean Pollutant Concentration The-flow-weighted average concentration of a pollutant measured in an urban stormwater runoff event. Hydrologic Soil Group The qualitative rating assigned to indicate the minimum rate of infiltration obtained for bare soil after prolonged wetting. These are Group: A - soils with low runoff potential and high infiltration rates; B - soils with moderate infiltration rates; C - soils with low infiltration rates; and D - soils with high runoff potential. Intensely Developed Area A term defined by the Chesapeake BAy Critical Area Critical in which either an area of equal to or greater than 20 contiguous acres or the entire upland portion of a municipality within the Critical Area has predominately residential, commercial, institutional and/or industrial development and relatively little natural habitat. The area must have housing density equal to or greater than 4 dwelling units per acre (DU/Ac.); a concentration of industrial, institutional, or commercial uses; or public sewer and water collection and distribution systems currently serving the area and a housing density of greater than 3 DU/Acre. InterJurisdictional Watershed A watershed with drainage boundaries that cross governmental boundaries. An example is the Patapsco River Watershed which includes portions of five local jurisdictions - Carroll, Baltimore, Howard, and Anne Arundel counties and Baltimore City. IntraJuriedictional Watershed A watershed with the drainage boundaries within a single governmental jurisdiction's boundaries. An example is the Magothy River watershed in Anne Arundel County. himited Development Area A term defined by the Chesapeake Bay Critical Area Criteria. The term describes any area currently developed in low or moderate intensity uses that contain areas of natural plant and wildlife habitat and the quality of runoff from such areas has not been substantially altered or degraded. The Intensely Developed Area (IDA) must have either a housing Gls-3 density from 1 to 4 dwelling units per acre; area not dominated by agriculture, forest, barren land, surface water, or open space; areas with characteristics of the IDA but less than 20 acres; or areas with public water or sewer or both. Management Practices (Controls) Also known as controls. These water quality control measures include source,erosion, and stormwater runoff controls. Mitigate To reduce a water quality or plant and wildlife habitat impact by requiring compensation for or replacing the affected area. Natural Soil Groups Soils assembled into groups having similar major properties and features. Natural soil groups are arranged in order of increasing limitations or problems for most uses. Groups are divided on the basis of drainage class, depth, permeability, flooding, and stoniness and rockiness. Subgroups are divided based on slope steepness. Offset A structure or actions that compensates for undesirable impacts. It is defined by the Chesapeake Bay Critical Area Criteria, offsets must be provided on or off a proposed development site in the Critical Area for the amount of pollutant loading that cannot be reduced to at least 10 percent of the predevelopment levels. The offsets must provide the equivalent water quality benefits and be obtained within the same watershed. Priority Watershed A watershed chosen by the user of this guide. Resource Conservation Area A term defined by the Chesapeake Bay Critical Area Criteria. Such areas have mostly wetlands, forests, and forestry activities, abandoned fields, agriculture, fishery activities, aquaculture, or less than one dwelling unit per 5 acres. Retrofit Control Opportunities Public open space, existing stormwater drainage structures, or other circumstances - revealed during a field survey of an analysis area - where retrofit control measures could be installed. Rivershed Another term for watershed. Gls-4 Runoff Controls A collection of management practices applied to stormwater runoff affecting peak discharge, volume, and/or water quality. The major categories include: infiltration, infiltration/ filtration/ flow attenuation, trapping, storage/release, natural systems, and physical treatment. Slope The steepness of the land determined by topography. Slope is expressed as a percentage, a gradient ratio, or as the degree of inclination of the land. Slope Map A topographic map that shows the steepness of the land. The slope ranges, or zones, vary with the intended use of the map and are represented by different colors or shading patterns. Soil Brodibility (K Factor) A measure of the susceptibility of bare surface soil to erosion. The K-factor is a component of an established equation for estimating potential erosion from a field or watershed (the Universal Soil Loss Equation). source Control A class of management practices that are non-structural, and affect human activities and living patterns. These controls prevent, reduce, or eliminate pollutants on the land surface prior to rainfall. Storawater Runoff Control A class of management practices that infiltrate, spread, filter, store, screen, settle, or treat the runoff. Subcreekshed A drainage area contributing to the total drainage area of a creekshed (subwatershed). Subwatershed A drainage area, two or more of which make up the total drainage area of a watershed. In a river watershed, the tributary creeks normally are called subwatersheds. Unusual Runoff-Related Pollutant Source An urban land use or activity that can generate higher pollutant concentrations or unusual pollutant types. Urban Areas Areas in which the construction of urban development has been completed and the land stabilized. Urban Area Field Survey Checklist A checklist to guide the user in his or her assessment of physical conditions and retrofit opportunities in an urban 'A Gls-5 area. Urban Area Retrofit Potential The potential for application of water quality control measures in an urban area. Urban Land One Development that includes residential, commercial, institutional, industrial, and transportation land uses. Urban Retrofit A control measure designed to improve the water quality of urban stormwater runoff in urban areas. Urban Retrofit Management Practices Controls to manage or elimate pollutants in urban stormwater runoff. Urban Retrofit Planning Method A six step method planning an urban retrofit for stormwater runoff. Watershed The largest scale of drainage area used in the Urban Retrofit Planning Method. Gls-6 Resource Directory Res-1 RESOURCS DIRECTORY Detailed information about specific stormwater-water quality management practices, physical and design characteristics, and application case studies can be found in the information sources in this section. Remember that most of the discussions in these publications address either newly developing urban areas or other water problems (i.e. combined sewer overflows) and do not address directly existing urban areas. However, many of these management practices, if applied creatively and under the proper site conditions, may be used in developed areas. Advanced Drainage Systems, Inc. "ADS Tubing: Nice to Have Around the House". Columbus, Ohio. 1986. Athanas, C. Wetland Basins for Stormwater Treatment. Horn Point Environmental Labs. University of Maryland. Prepared for Maryland Department of Natural Resources. Annapolis. 1986. Austin City Department of Public Works. Design Guidelines for Water Quality Control Basins. Watershed Management Division. Austin, Texas. 1986. Bray, M. and E. Bradley. Erosion and Sediment Control Practices: An Annotated Bibliography. Maryland Department of Natural Resources. Annapolis. July 1983. Citizens Program for the Chesapeake Bay. The Baybook: A Guide to Reducina Water Pollut ion at Home. Baltimore. 1985. Gray, D. and L. Leiser. Biotechnical Slope Protection and Erosion Control. Van Nostrand Reinhold Company. New York. 1982. Hannebaum, L. Landscape Desion: A Practical Approa@h. Reston Publishing Co., Reston, Virginia. 1981. Kent, E., S. Yu, and D. Wyant. "Drainage Control Through Vegetation and Soil Management". Prepared for Presentation to the Annual Meeting of the Transportation Research Board, Washington, D.C. January 1982. Virginia Highway Transportation Research Council. Charlottesville, Virginia. December 1981. McCuen, R. Stormwater Manacement in Coastal Areas. Prepared for the Maryland Department of Natural Resources. University of Maryland. College Park. September 1982. Margolin, M. The Earth Manual: How to Work on Wild Land Without Tamina It. Heywood Books. Berkeley. 1985. Martin, S. Relationship of Fine-arained Materials to Pollutant Parameters. Addendum to Task I, Development of New Criteria for Res-2 Sediment Traps and Basins. Prepared under the Erosion and Sediment Control Practices Contract for the State of Maryland Department of Natural Resources. 1985. Martin, S., Jones Falls Watershed Urban Stormwater Runoff Project, Volume II: Report of Project Results, Regional Planning Council, November, 1985. Martin, S. Urban Stormwater Retrofit Analysis Project: Site and BMP Assessment. Prepared for Baltimore City, Maryland. Regional Planning Council. Baltimore. February 1986. Martin, S. and P. Clayton, Jones Falls Urban Stormwater Runoff Project. Technical Summary, Regional Planning Council, December, 1986. Maryland Soil Conservation Service. Maryland Specifications for Soil Erosion and Sediment Control. Maryland Water Resources Administration. Annapolis. 1983. (being revised) Maryland Water Resources Administration. The Effects of Alternative Stormwater Manauement Desion Policy on Detention Basins. Sediment and Stormwater Division. Annapolis. 1983. Maryland Water Resources Administration. Standards and Specifications for Infiltration Practices. Maryland Department of Natural Resources. Annapolis. 1984. Maryland Water Resources Administration. Inspector's Guidelines for Stormwater Manacement Infiltration Practices. Maryland Department of Natural Resources. Annapolis. 1985. Maryland Water Resources Administration. Minimum Water Quality and Plannina Guidelines for Infiltration Practices. Maryland Department of Natural Resources. Annapolis. 1986. Maryland Water Resources Administration. Feasibility and Design of Wet Ponds to Achieve Water Ouality Control. Sediment and i-tor-mwa@Ee--rDivlislon. Maryland Department of Natural Resources. Annapolis. 1986. Maryland Water Resources Administration. Guidelines for Constructing Wetland Stormwater Basins. Sediment and Stormwater Division. Department of Natural Resources. Annapolis. March 1987. Meckley, P., L. Wrabel, B. Brun, T. Hall, and B. Holmgren. Forest Buffers as a Best Manaaement Practice. Maryland Department of Natural Resources. Annapolis. 1986. Metropolitan Washington Council of Governments, Urban Best Manaaement Practices: A Practical Manual For Planning and Desioning Urban BMP9. Washington, D.C. July 1987. Res-3 Metropolitan Washington Council of Governments. A Framework For Evaluatina Compliance With The 10% Rule In The Critical Area. Prepared for the Maryland 61--ti@-al j@rea Commission and the office of Environmental Programs. Washington, D.C. April 1987. Novotny, V. and G. Chesters. Handbook of Nonpoint Pollution: Sources and Manaaement. Van Nostrand and Reinhold Company. New York, N.Y. 1981. Pitt, D., W. Gould, and L. LaSota. Landscape Design to Reduce Surface Water Pollution in Residential Areas. Water Resources Information Bulletin No.5. University of Maryland. Cooperative Extension Service. College Park. 1986. Pitt, R. Urban Bacteria Sources and Control by Street Cleaning in the Lower Rideau River Watershed Ottawa, Ontario. Prepared for the Rideau River Stormwater Management Study. Blue Mounds, Wisconsin. May 1982. Pitt, R. Characterizina and Controllina Urban Runoff Throuah Street and Sewerage Cleaning. Prepared for U.S. Environmental Protection Agency. Washington, D.C. EPA-600/S2-85-038. Pitt, R. The Incorporation of Urban Source Area Controls in Wisconsin's Priority Watershed Projects. Wisconsin Department of Natural Resources. Madison. 1986. Pitt, R. Manual of Practice for the Desian of Construction Site Erosion and Stormwater Runoff Controls. Wisconsin Department of Natural Resources. Madison. 1986. Schueler, T., R. Magill, M. Sullivan, and C. Wiegand. "Comparative Pollutant Removal Capability, Economics and Physical Suitability of Urban Best Management Practices in the Washington D.C. Metropolitan Area". Proceedings of Symposium on NonPoint Pollution Abatement, Marquette University, Milwaukee, WI. April 1985. Silverman, G., M. Stenstrom, and S. Fam. "Best Management Practices for Controlling Oil and Grease in Urban Stormwater Runoff". The Environmental Professional. Vol. 8. pp. 351-362. 1986. Tourbier, T. and R. Westmacott. A Handbook of Measures to Protect Water Resources in Land Di;velopment. The urban Land Institute. Washington, D.C. 1981. University of Maryland. Cooperative Extension Service. Lawn Care in Maryland. Bulletin No. 171. College Park. Rev. 1977. U.S. Department of Agriculture. Soil Conservation Service. Conservation Plants for the Northeast. Program Aid No. 1154. Washington, D.C. November 1977. Res-4 U.S. Department of Agriculture. Soil Conservation Service. Technical Guide for Wetland Manaaement. Maryland Field Office. College Park. 1986. U.S. Environmental Protection Agency. Relationship Between Diameter and Heichts for the Desian of a Swirl Concentrator as a Combined Sewer overflow Regulator. EPA-670/2-74-039. 1974. U.S. EPA. The Swirl Concentrator as a Grit Separator Device. EPA-670/2-7i-026. 1974. U.S. EPA. Urban Stormwater Manacement and Technolocy: An Assessment. National Environmental Research Center. Cincinnati. EPA-670/2-74-040. December 1974. U.S. EPA. Water Quality Manaaement Planning for Urban Runoff. Washington, D.C. EPA-440/9-75-004. December 1974. U.S. EPA. The Helical Bend Combined Sewer Overflow Regulator. EPA-600/2-75-062. 1975. U.S. EPA. 208 Areawide Assessment Procedures Manual. Prepared by Hydroscience, Inc. EPA 600/9-76-014. Cincinnati. July 1976. U.S. EPA. Methods to Control Fine-Grained Sediments Resulting From Construction Activity. Office of Water Planning and Standards. Washington, D. C. December 1976. U.S. EPA. Urban Runoff Pollution Control Technology Overview. Municipal Environmental Research Laboratory. Cincinnati. EPA- 600/2-77-047. March 1977. U.S. EPA. Catchbasin Technolocy Overview and Assessment. Municipal Environmental Research Laboratory. Cincinnati. EPA- 600/2-77-051. May 1977. U.S. EPA. EPA Technology Transfer Capsule Report. Swirl Device for Regulating and Treating Combined Sewer Overflows. EPA-625/ 2-77-012. 1977. U.S. EPA. A Statistical Method for the Assessment of Urban Stormwater. EPA 440/3-79-023. Washington, D.C. May 1979. U.S. EPA. Laboratory Evaluation of Methods to Separate Fine Grained Sediment from Stormwater. Municipal Environmental Research Laboratory. Cincinnati. EPA-600/2-79-076. July 1979. U.S. EPA. Combined Sewer Overflow Treatment !Zy Screening and Terminal,Pondinc: Fort Wayne, Indiana. Municipal Environmental Research Laboratory. Cincinnati. EPA-600/2-79-085. August 1979. U.S. EPA. Screenina/Flotation Treatment of Combined Sewer Overflows, Volume II: Full-Scale Operation, Racine, Wisconsin. Res-5 Municipal Environmental Research Laboratory. Cincinnati. EPA- 600/2-79-106a. August 1979. U.S. EPA. Disinfection/Treatment of Combined Sewer Overflows, Syracuse, New York. Municipal Environmental Research Laboratory. Cincinnati. EPA-600/2-79-134. 1979. U.S. EPA. Field Evaluation of a Swirl Dearitter at Tamworth, New South Wales, Australia. Municipal Environmental Research Laboratory. Cincinnati. EPA-600/S2-81-063. June 1981. U.S. EPA. Use of Veaetative Filter Zone to Control Fine-Grained Sediments from Surface Mines. Industrial Environmental Research Laboratory. Cincinnati. EPA-600/S7-81-117. August 1981. U.S. EPA. Swirl and Helical Bend Pollution Control Devices. Municipal Environmental Research Laboratory. Cincinnati. EPA- 600/8-82-013. July 1982. U.S. EPA. Evaluation of Catchbasin Performance for Urban Stormwater Pollution Control. Municipal Environmental Research Laboratory. Cincinnati. EPA-600/2-83-043. June 1983. U.S. EPA. Stormwater Hydrological Characteristics of Porous and Conventional Paying Systems. Municipal Environmental Research Laboratory. Cincinnati. EPA-600/2-83-106. October 1983. U.S. EPA. Results of the Nationwide Urban Runoff Proaram: Volume I - Final Report. Washington. December 1983. U.S. EPA. Swirl and Helical Bend Reaulator/Concentrator for Storm and Combined Sewer Overflow Control. Municipal Environmental Research Laboratory. Cincinnati. EPA-600/ S2-84-151. October 1984. Virginia State Water Control Board. Urban Best Management Practices Handbook. Planning Bulletin No. 321. Richmond. 1979. Res-6 References Ref -1 RZFZRZNCES Anderson, J., E. Hardy, J. Roach, and R. Witmer, A Land Use and Land Cover Classification System for Use with Remote Sensor Data, Geological Survey Professional Paper 964, Government Printing Office, Washington, 1976. Driscoll, E. Rainfall/Runoff Relationships from the NURP Runoff Database, Presented at the Stormwater and Quality Models Users Group Meeting, Montreal, Quebec, September 8-9, 1983. Earth Satellite Corporation, Comparative Evaluation of NHAP CIR Photooraphy, Simulated SPOT, and LANDSAT TM Data for Meetina Local/Reaional Plannina Information Needs, Prepared for the Regional Planning Council, January 31, 1985. Leopold, L., F. Clarke, B. Hanshaw, and J. Bailey, A Procedure for Evaluatina Environmental Impact, Geological Survey Circular 645, Washington, 1971. McAllister, D. Evaluation in Environmental Planning: Assessing Environmental, Social, Economic,- and Political Trade-offs, MIT Press, Cambridge, Mass., 1980. Makower, J. The Map Catalog, Tilden Press, New York, 1986. Martin, S., Jones Falls Watershed Urban Stormwater Runoff Project, Volume II: Report of Project Results, Regional Planning Council, November, 1985. Martin, S. and P. Clayton, Jones Falls Urban Stormwater Runoff Project. Technical Summary, Regional Planning Council, December, 1986. Martin, S. Index System for Measurina Water Quality Chance, Seminar Presentation to Anne Arundel County, Regional Planning Council, Baltimore, August 27, 1985. Metropolitan Washington Council of Governments. A Framework For Evaluatipq Compliance With The 10% Rule In The Critical Area. Prepared for the Maryland Cilii@@a-l i-r-ea C-ommission and the Office of Environmental Programs. Washington, D.C. April 1987. Metropolitan Washington Council of Governments, Urban Best Manaaement Practices: A Practical Manual For Planning and Designina Urban BMPs. Washington, D.C. July 1987. Metropolitan Washington Council of Governments, Urban Best anagement Practices: A Practical Manual For Planning and Design, Draft, Washington, January 1987. M Ref-2 Metropolitan Washington Council of Governments. Technical Documentation of a Simple Urban Runoff Load Estimation Technique Preliminary Draft, New Guidebook Review Paper No. 1, Washington, D.C. , 1986. Odum, W. and M. Hawley, "Impacts of Urban Runoff on Estuarine Ecosystems", Impacts on Estuarine Ecosystems, 1986. Ott, W., Environmental Indices: Theory and Practice, Ann Arbor Science, Ann Arbor, 1978. Photo Science, Inc., "Design and Use of Slope Maps", Gaithersburg, 1979. Regional Planning Council, A Proposal for a Land Use/Land Cover Classification Scheme for the Baltimore Region, 1983. Jones Falls Watershed Urban Stormwater Runoff Project Interim Report, Baltimore, September 1982. Land Use in the Baltimore Region 1976. Schueler, T., R. Magill, M. Sullivan, and C. Wiegand. "Comparative Pollutant Removal Capability, Economics and Physical Suitability of Urban Best Management Practices in the Washington D.C. Metropolitan Area". Proceedings of Symposium on NonPoint Pollution Abatement, Marquette University, Milwaukee, WI. April 1985. State of Maryland, Chesapeake Bay Critical Area Commission, A Guide to the Chesapeake Bay Critical Area Criteria, Annapolis, May 1986. Chesa eake PAI Critical Area Protection Program, Natural Resources Article SS 8-1801-8-1816. State of Maryland, Office of Environmental Programs, Maryland Water Quality Inventory, State 305(b) Report Prepared Pursuant to Provisions of the Federal Clean Water Act (PL 92-500 and PL 95- 217), Baltimore, 1986. State of Maryland, Department of State Planning, Natural Soil Groups Technical Report, Publication No. 199, Baltimore, December 1973. U.S. Department of Agriculture. Soil Conservation Service, Urban Hydrology for Small Watersheds, Technical Release 55, Washington, June 1986. U.S. Department of Agriculture, Soil Conservation Service, in cooperation with the Maryland Agricultural Experiment Station, Soil Survey qf Anne Arundel County, Maryland, February 1973. Ref-3 . Soil Survey of Baltimore City, Maryland, In Preparation. Maryland, March 1976. . Soil Survey of Baltimore County, Maryland, October 1969. , Soil Survey of Carroll County, Soil Survey of Harford County, Maryland, August 1975. Soil Survey of Howard County, Maryland, July 1968. University of Maryland, Cooperative Extension Service, Maryland Soils, Extension Bulletin No. 212, College Park, May 1967. U.S. Department of the Interior. Geological Survey. Slope Mappina. U.S. Government Printing Office. Washington, D.C. U.S.. Environmental Protection Agency. Results of the Nationwide Urban Runoff Proaram: Volume I - Final Report. Washington. December 1983. U.S. Environmental Protection Agency. Statistical Method for the Assessment of Urban Stormwater, EPA 440/3-79-023, Washington, May 1979. U.S. Environmental Protection Agency, 208 Areawide Assessment Procedures Manual, Prepared by Hydroscience, Inc., EPA 600/9-76- 014, Cincinnati, July 1976. Ref-4 I-- I I t I I I I I I I I I I I I 11 - 1 3 6668 0-0000 -8906 - I -t