inventory of land use within the Mobile-Tensaw River Delta, 1981-1982

[From the U.S. Government Printing Office, www.gpo.gov]

DAUPHIN ISLAND SEA LAB

SPECIAL REPORT

REPORT No.

AN'INVENTORY OF LAND USE WITHIN THE MOBILE-TENSAW

RIVER DELTA, 1981-1982.

.(With-Map Appendices)

PREPARED BY

Judy P. Stout
and
Hugh M. Dowling

MARINE ENVIRONMENTAL SCIENCES CONSORTIUM

Dauphin Island Sea Lab
Dauphin Island, Alabama 36528

The prepar 'ation of this document was financed in
part by a Federal grant from the office of Coastal
Zone Management, National Oceanic and. Atmospheric
Administration as authorized by the Coastal Zone
Management Act'of 1972; Administered by the Alabama
Coastal Area Board.

AN INVENTORY OF LAND USE WITHIN THE MOBILE-TENSAW

RIVER DELTA, 1981-1982.

(With Map Appendices)

PREPARED BY

Judy P. Stout
and
Hugh M. Dowling

Marine Envirorurental Sciences Consortium

FOR

Alabama Coastal Area Board

CAB Technical Re'port 81-49B
Dauphin Island Sea Lab Technical Report 82-004

DECEMBER, 1982

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AN INVENTORY OF LAND USE WITHIN THE MOBILE-TENSAW
RIVER DELTA, 1981-1982.

INTRODUCTION

The Mobile-Tensaw River Delta comprises approximately .115,000
acres of wetland habitats bisecting the northern third of Mobile and
Baldwin Counties Alabama. Though unsuited for many land use
categories, the Delta has hosted a lengthy history of human h;jbitation
which may date back as early as 10,000 B.C. Earliest Indian
utilization was for campsites, hunting, fishing and transportaLion.

French colonization of coastal Alabama in the early 1700's
represents the first European use of the Delta. Bluffs, particularly
along the western margins, were the sites of several French settle-
ments. Individual farmsteads were probably located throughout the
Delta on higher areas.

Following admission of Alabama as a state, in 1918, activities
around the margins of the Delta increased.with the expanding port use
of both Mobile, to the west, and Blakeley, to the east. Subsequent
history of land use in the Delta is tied to dock expansions,
.lumbering, recreation, hydrocarbon exploration activities, and energy
and utility corridors.

The current inventory surveys all 1981-82 land uses in the Delta.
The. inventory -is limited to Delta lands at or below the 10-foot
contour as far north as the Alabama River cutoff (Figure 1).

METHODOLOGY

land use data was collected coincident with wetland habitat
mapping of the same area. All areas were surveyed by boat between
January 1981 and December 1982. Additional'information was obtained
through two aerial survey missions. Locations of land use units were
-recorded on color infra.-red photographs 1:15,000 (NASA Mission JSC
project 0839,, October, 1979). Where extensive,.acreage of impact was
determined from aerial photographs using a K & E Polar Planimeter
(Model 62002, 997. accuracy).

RESULTS.,

A total of 22 land use tategories were identified for the Delta.
These are summarized in Table 1 with the number of units of each
tabulated. Acreage impacted by the major land use categories is
detailed in Table 2.

The most frequently encountered land use was private camps,
rep resented by 234 units. These are located along the margins of the
rivers, creeks and bays throughout the Delta (See Figure 1). Camps
consist of both floating and raised wood-frame structures; boating
docks or piers are often a8sociated with the camps. Most camps use
less than 0.25 acres each. Camps are rarely permanently occupied, but

are used seasonally for fishing and hunting.' Camps which showed
extensive damage and disrepair were considered1to be. abandonled and
were not included in the inventory.

I.ndustrial/business land use units were the second most abundant
category and because of their individual.sizes cover the greatest
area. This category includes businesses and industries as diverse as
truck stops, lounges, tank farms, paper companies, and large port and
warehouse areas. These units are concentrated along U.S. Highway 90*
and the east bank of the Mobile River. Water use and water quality
are the less apparent, but possibly more significant impacts of these
land use units.

The Mobile-Tensaw River Delta acts as an extensive barrier to
access between northern Mobile and Baldwin Counties. For this reason,
it has been necessary to establish a number of corridors through the
Delta. . These are utilized for transportation (L & N Railroad),
,utilities (Alabama Power), and petroleum pipelines (United Gas), as
examples. A total of 20 corridors are summarized in Table 1 and their
descriptions and land use impact are noted in Table 2.

Five oil exploration sites are currently located within the
surveyed area. Rig sites usually appear as'T or L-shaped canals
dredged from navigable waterways into wetlands.. Dredged material is
side-cast into clear-cut wetlands on one or both canal banks. The
earliest site (Exxon) was dredged in 1963 and the most recent
(Superior).was initiated in 1981.during this'inventbry. Four sites
have been abandoned; none have been reclaimed. Major oil reserves
were found at the Mobile River Superior site and production, permits
for this site will be sought in the future. Currently, there are
,permit requests for two additional exploration projects in the Delta.
.Their locations have been indicated on the land use map. Acreage
impacted to date by exploration efforts is summarized in Table 3.
This land use category will probably increase in the'future due to
critical energy demands and the potential of the area.

Within the Delta the land use with the most extensive impact is
logging efforts. The 1981-82 survey revealed over 7,400 acres which
had obviously been recently logged (See Table 4). This estimate,
however, falls far short of the actual acreage impacted since man
began to exploit the abundant timber resources available. Mohr (1878)
discusses the. gigantic.cypress of the Delta, up to forty feet in
circumference, and their utilization as shingles, planks, cabinetry
and increasing use as rot-resistent posts and pilings. By 19281
Harper reports.for cypress ...

"it does not constitute a large proportion of the
forest ofany region except the Mobile Delta,
(probably most to the original supply there has
been cut out). Itgrows so slowly in the swamps
that it does not have muc-h chance to restore itself
after logging operations." p. 65

Evidence of historical logging efforts is apparent in large stumps
and, from the air, trails along which logs were dragged to the

navigable r-jivers are still visible. However, it is not possible to
assess the textent of the historical impact 6f this activity on Delta
wetlands. Tarticularly impacted by recent logging are the easily
accessible nLatural levees of the upper Delta.

REFERENCES CITED

Harper,, R. M. 1928. Economic Botany of Alabama. Part 11. Geological
SaLrvey of Ala. , Monogr. No. 9. 357 p.

Mohr, ir; 1878. The forests of Alabama and their products. Part II,
pp,.. 221-235. IN: S. Birney (ed.). Handbook of Alabama: A
ccimplete index to the state; with a geological map and. an
apq)endix of useful tables. Mobile Register, Print, Mobile,
Alaibama.