Coastal wetlands of San Diego County

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

*'The C 'oa@tal Wetlands
of San Diego County
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SAN DIEGO HISTORICAL SOCIETY-TICOR COLLECTION

San Diego Bay

CALIFORNIA STATE COASTAL CONSERVANCY

Penny Allen, Chairperson
Reginald E Dupuy, Public Member
Marcus E. Powers, Public Member
Margaret Azevedo, Public Member
LaFenus Stancell, Designated Representative, Department of Finance
Gordon E Snow, Designated Representative, Resources Agency
Michael Wornum, California Coastal Commission

Senate Representatives
Robert Beverly
Barry Keene
Henry Mello

Assembly Representatives
Jim Costa
Frank Hill
Jack O'Connell

This book was produced by the State Coastal Conservancy in conjunction with the Batiquitos Lagoon
Foundation. Grant funds were provided by the Office of Ocean and Coastal Resource Management of the
National Oceanic and Atmospheric Administration.

The Coastal Wetlands
of San Diego County

STATE OF CALIFORNIA
George Deukmejian, Governor
Gordon Van Vleck, Secretary of Resources

CALIFORNIA STATE COASTAL CONSERVANCY
Peter Grenell, Executive Officer

Laurel Marcus, Research and Writing
Anna Kondolf, Design and Layout

Rasa Gustaitis, Editing Julie Goodnight, Paste-up
Jan Jue, Copy Editing Design & Type Inc., Typesetting
Donna Greene, Word Processing Warren's Waller Press Inc., Printing
Denise Sullivan

Introduction

We abuse the land because
we regard it as a commodity
belonging to us. When we see
land as a community to which
we belong, we may begin to
use it with love and respect.

Aldo Leopold

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. .. . . .......

T
he return of the California Gray Whale from near extinction to a coastal tourist
attraction is one of the few environmental success stories of the past 20 years. The
Light-footed Clapper Rail, a secretive bird of tidal marshes, has not been so lucky and
remains close to extinction. The ducks and geese that once crowded the winter sky return
each year in ever smaller numbers to their coastal wintering grounds. The fish of local bays
and lagoons are no longer so numerous and easy to catch. All these animals and many
more are wetland dwellers for all or part of their lives. In California the wetlands-the
marshes, mudflats, swamps, estuaries, and lagoons-they need to survive are nearly
gone.
Why should we care about some boggy land and a few ducks? Perhaps because
wetlands are the most productive ecosystem in the world. The coastal wetlands support
not only a cast of resident fish, crabs, worms, birds, and mammals, but also a large
contingent of visiting wildlife. The bird visitors-shorebirds, terns, gulls, ducks, geese,
and other water lovers-stop at wetlands along their migrations from nesting sites in
Alaska and central Canada. They need to rest and, most importantly, to feed. Each coastal
wetland is a refueling station and an essential link in the migratory route. Marine fishes
annually move into bays and tidal wetlands to spawn; their offspring may spend a year
maturing in the productive, calm waters. Marshes and mudflats provide delicacies to
2

humans as well; clams, crabs, fish, ducks, and geese are all wetland creatures. Besides
being marvelous wildlife habitat, wetlands are good filters. They can absorb moderate
amounts of nutrients and cleanse stormwater. To many, wetlands are aesthetically pleas-
ing-the solo flight of a heron at dusk or the magical interplay of dawn light on water and
marshes bring solace and psychological well-being. But maybe the most important reason
we care for wetlands and their wildlife is the same reason we want to save the gray whale-
they deserve to share this earth and need our protection to survive.
Coastal wetlands are among the most endangered habitat types in the world, second
only to tropical rain forests. The United States loses more than 18,000 acres of coastal
wetlands every year. On the California coast, 75 percent of the wetlands have been
destroyed in less than 140 years, bringing the term "endangered" to many wetland-
dependent species.
San Diego County's wetlands may prove to be the most threatened natural resource on
the California coast. By 1900, human activities had modified all 16 wetlands. Since the
1970s, the purchase of many of these areas with public funds for wildlife preserves, as well
as regulation of coastal development, has largely stopped direct wetland losses. But the
county's population grew at a rate of 35-40 percent this decade, and the associated building
boom has caused large increases in erosion of coastal watersheds. Wetlands are the
endpoints of these watersheds, and they are rapidly filling in. Unless further development
is guided to protect wetlands and watersheds together as a system, San Diego's coastal
wetlands and their wildlife will soon disappear entirely.
The California State Coastal Conservancy works to protect what wetlands remain.
Created in 1978 to preserve, enhance, and restore the resources of the coast, this non-
regulatory agency provides technical assistance and funding to local governments and
nonprofit organizations. The Conservancy has produced this booklet with a grant from the
Office of Ocean and Coastal Resource Management of the National Oceanic and Atmo-
spheric Administration. The aim is to provide an easily read discussion of coastal wetlands
and watersheds for the public and local decision makers. We have also included sections
on the ocean's influence on wetlands, endangered species, wildlife, wetland regulation
and restoration, and an inventory of 16 wetlands.
In a rapidly growing region such as San Diego, wetlands and their watersheds can easily
be destroyed in the rush for short-term profit. Losing our coastal wetlands means losing
some of the richness of our world. The more uniform and built-over the landscape
becomes, the more lifeless and boring it seems. Situated in the midst of a crowded city, a
wetland is a pleasing slice of openness. It adds variety, beauty, and interest to our daily
lives and teaches us and our children about the intricacies of nature. The loss of wetlands
diminishes the quality of our lives and denies a part of our natural heritage to future
generations. We hope this booklet will assist the people of San Diego in understanding and basket cockle (Clinocardium
preserving their wetlands. nuttallii)
3

Coastal Wetlands:
The Dynamic Edge of a Continent

Such is the force of water that
it will with gentle pressure
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shape itself to every vessel and
yet pierce the very rock.

Emperor Meiji

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Los Pefiasquitos Lagoon <

W
etlands form a thin edge along the steep and ragged California coast. Wedged into
the few protected sites available along this geologically active rim of the continent, MAXIMUM
wetlands fill river mouths and lagoons, and also line bays. Their appearance along the
Pacific coastline coincided with sea level rise following the last ice age. About 18,000 years
ago, sea level was some 400 feet lower than it is now, and the shoreline lay miles to the west.
The sites of today's coastal cities were far inland. Over thousands of years, rivers and MINIMUM
creeks cut canyons and hollowed wide valleys. As the glaciers melted, sea level rose and
flooded the river and creek valleys. These "drowned" valleys became the bays and lagoons HEAVY LINE=
of today. Eventually, sea level rise slowed enough to equal the geologic uplift of the MODERN SHORELINE
continent. The shoreline took on a contour very close to its present location. Sand buildup
along the new shoreline formed beaches and enclosed lagoons and bays. Landward, alL@S ' @O San Diego
sediment flowing down creeks slowly created mudflats and marshes. 0
For many thousands of years before the Spanish arrived, the wetlands remained in an
equilibrium between land and sea. Large numbers of Native Americans lived near the During the past twenty thousand
lagoons and bays of the San Diego coast. Excavations of the middens, or garbage heaps, of years, sea level has risen much
these early residents turned up numerous shells of estuarine mussels and clams. These higher and has receded much
animals only occur in tidal embayments and indicate that several of the lagoons (Los lower than its present day level.
Pefiasquitos, San Elijo, and Batiquitos) were fully tidal systems prior to European settle-
ment. These same lagoons have changed dramatically in the last 200 years and now are
rarely open to the tide. A closer look at the physical processes that shape coastal wetlands
may explain why.

Between Land and Sea
Poised on the edge of both land and sea, the wetland is a true middle ground, reflecting
conditions and changes in both these elements. Streams bring in fresh water, eroded soil, and
sometimes pollutants from the land. The sea brings in tidal water with its salts, minerals, and
sands twice daily. The result of this intermingling of land, water, and sea is a dynamic
envirorunent that is both unique and fragile. The processes that shape, change, and nourish
wetlands are complex and are primarily controlled by the wetland's watershed and the sea.

The Watershed
A watershed or drainage basin is the land area drained by a stream system. Each coastal
wetland is the endpoint of a watershed where the stream system reaches the sea. The size
and shape of each watershed is determined by the particular geology and steepness of the
land. Several of San Diego's coastal wetlands (the San Diego, San Luis Rey, and Santa
Margarita rivers) have very large watersheds, while some are quite small (Buena Vista and MAXMUIV
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HEAVY LINE N
MODERN SH@ORELINE

Las Flores creeks). But no matter the size, the physical processes are similar.
5

Erosion and sedimentation shape the watershed. Soil erosion is a natural process and,
except during large floods and after fires, occurs very slowly. The steepness of the land,
the type of soil, and the thickness of the vegetation determine the susceptibility of a
watershed to erosion. Steeper hillsides are more erodible than flat areas because water
runs off the ground faster, more easily eroding soil particles. Hard, rocky soils erode less
than sandy, loose soils. Soil types in San Diego's coastal watersheds vary greatly. Sandy
soils, which cover many of the bluffs surrounding wetlands, are often the most erosion-
prone soils. In its natural state, vegetation blankets the soil and protects it from erosion.
The thicker and more substantial the vegetative cover, the more the soil is protected. For
example, chaparral shrubs have dense foliage, which deflects raindrops, and thick root
systems, which bind the soil. Annual grasses, with shallow roots and minimal foliage,
Undisturbed wetland and provide much less protection. Where vegetation is removed, the soil is left exposed and is
watershed easily carried away by rain, dramatically increasing the rate of soil erosion.
Most erosion occurs during intense downpours. San Diego's climate is relatively mild,
with an average of 10 inches of rain concentrated in the winter months. Rain may fall in a
series of small storms or in a few intense downpours. These downpours have produced
over 1.2 inches of rain in one hour, causing water to run off the land rapidly and in large
volumes, carrying large amounts of soil with it.
Once soil particles are eroded from the land, they are carried by stormwater into
streams. In the steep, upper areas of the drainage basin, stream flow will be rapid, but as
the stormwater reaches the flatter lands near the coast, the stormwater slows down. As the
water slows, the heavier soil particles, such as sand, drop out. Vegetation in the stream
channel, typically composed of willows or cottonwoods, further slows the water and
causes sediment to deposit. In this way, deposited sands gradually build up the floodplain
of rivers and creeks. Some of the smaller, lighter soil particles may also deposit on the
floodplain, or they may travel all the way to the estuary before settling. In large floods, the
volume and speed of the water are so great that the stormwater does not slow down until it
reaches the ocean, and sediment is deposited on beaches and offshore. During large
storms, floodwaters may erode away the stored sediment from the floodplain and move it
further downstream into the estuary. A very large storm may flush stored sediment not
only from the streams, but also from the estuary.
We all want to believe that the earth beneath our feet is solid and unchanging, a
monument of security. But the land is constantly being transformed. The processes of
erosion and sedimentation in watersheds turn mountains to hills and, over time, nourish
beaches with the sands. River and streams continuously change form, undergoing small
and sometimes catastrophic alterations. A creek bank caves in, a small sandbar forms
along a stream meander; a flooding river jumps its banks and forms a new channel. The
land is dynamic, undergoing minor gully and rill erosion and occasional massive land-
slides. Change in one part of the watershed slightly to drastically alters downstream areas.

There is a dynamic balance between soil, stream, and water in each watershed that is
established, lost, and reestablished. When human settlement covers the watershed, this
balance is upset and the attempt of the system to reestablish an equilibrium can cause
problems both for people and coastal wetlands. Agriculture and urbanization have had
three primary effects on San Diego's coastal watersheds-land disturbance, construction
of dams and reservoirs, and increases in storm flows.

When land is cleared for agriculture or graded and formed to hold roads and buildings, Land Disturbance
the soil is left unprotected and prone to very high rates of erosion. Row crops or orchards,
oriented against the contour of the hill, have furrows and farm roads that easily erode.
Land development, even when completed with strict erosion control measures, can still
cause sedimentation should a summer thundershower occur or a sediment basin fail. Land
10
grading in the winter with inadequate control measures-a practice widely used in San
Diego County developments-can increase erosion up to 10,000 times the rate of a natural
drainage. Streets near housin developments are often covered with mud after a storm,
9
indicating erosion of the soil from the building site.
Land disturbance greatly increases the sediment loads in stormwater. Sediment fills in
stream channels, causing streams to jump their banks and flood surrounding lands.
Extensive development in the upper area of a watershed may produce so much sediment
that downstream channels clog, and the older city neighborhoods in the lower watershed
will flood. Sediment from land development can have devastating effects on coastal
wetlands. Buena Vista, Los Pefiasquitos, and Batiquitos lagoons have filled in with great
quantities of sediment; where streams enter these lagoons, large deltas can be seen.

Dams and Reservoirs The development of agriculture and cities in the and climate of San Diego has depended
on the creation of a water supply. Most major coastal streams have at least one dam and
reservoir. Much of the fresh water that naturally flowed to coastal wetlands is diverted to
farms and cities. These dams reduce the size of flood flows and thus also reduce the
flushing of sediment from estuaries. They also trap sand that would otherwise nourish
coastal beaches.

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Urban Storm Flows When a drainage basin is paved, the balance in the watershed changes greatly, just as it
does when land is cleared and plowed. Whether a year is dry or wet, the rate at which
rainwater flows off the land into the stream system depends on the groundcover in the
watershed. Natural vegetation and open land allow maximum percolation of water into
underground basins, or aquifers, with a slow release to streams. This natural filtering
system mediates the rise of floodwaters in the stream system, producing lower flows in
creeks that may last well into summer. When urban land is paved with concrete and
asphalt, little percolation occurs. Rainwater flows directly off these hard surfaces into
stream channels. Creeks carry enormous volumes of water for a few days following a
JA storm and then dry up early in the season. The natural stream channel, which formerly
carried smaller amounts of runoff, cannot handle this increased volume of water. These
larger storm flows erode the natural floodplain, turning the creek into a deep gully The
creek channel may erode both downward and outward, toppling riparian trees and

creating a wide, steep-banked arroyo. This erosion will continue until the creek is wide
enough to carry the new water volume and an equilibrium is reestablished. In a single
storm, this process can remove tons of sediment from floodplains, deposit it in coastal
wetlands, and destroy strearnside forest and property. To prevent flood damage, creek
channels are often lined with concrete. Although they may provide temporary protection
for one part of the stream, concrete channels accelerate storm flows and increase erosion of
natural channels downstream.
The effect of urbanization in a watershed on its coastal wetland may not be immediate.
The case of Buena Vista Lagoon affords a good example. During the dry period from 1965
to 1977, extensive urban development occurred in the watershed. Approximately half of
the creek's length was lined with cement, primarily in the lower watershed. During
1978-80, floods carried so much sediment down this channel that the eastern lagoon basin
was filled, smothering wetlands. The State spent over $1 million to remove this mud.
Most of the sediment came from Buena Vista Creek. Urban development had so
increased the volume of storm flows that a 20-foot-deep gully formed in the middle reach
of the creek. The creation of an arroyo was underway. Concrete channels had replaced
much of the natural floodplain below the gully, and the eroded sediment was carried
directly into the calm waters of the lagoon, where it settled. The open water and marsh of Above: Gully in Buena Vista
the lagoon were buried under tons of sediment. Later studies found the lagoon was filling Creek eroded by urban stormflows
in at a rate of 35,000 tons of sediment a year, a rate that would fill the entire lagoon in 10 to 20 is the major source of sediment
years. Similar problems can be seen in the watersheds of Mission Bay, San Dieguito, and filling in Buena Vista Lagoon.
San Elijo lagoons, Opposite Page: Rodriguez dam in
the Tijuana River watershed.

ARROYO FORMATION

POTENTIAL ERODIBLE
WEDGE BANKS
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. . ..........
ULTIMATE NEW FLOODPLAIN

___PLOODPLAIN___ FORMER FLOODPLAIN

AGGRADING STREAM DEGRADING STREAM
SEDIMENT IN EXCEEDS SEDIMENT OUT SEDIMENT OUT EXCEEDS SEDIMENT IN

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The Sea
The daily intrusion of tidal water is an essential and controlling element of coastal
wetlands. The San Diego coast has two high and two low tides daily The average tidal
range is about five feet, while the maximum yearly tidal range is ten feet. The maximum
high tide helps to define the upper boundary of a coastal estuary by inundating soils often
enough to create high salinity levels and eliminate all but the hardy salt marsh plants. This
upper tidal boundary-not the crashing surf-is the landward edge of the sea.
Tidal currents shape the wetlands' channels and shoreline. They distribute sediments
from watershed creeks throughout the estuary. Most of the finer particles are transported
out with the tide. Heavier particles settle, move, resettle, and eventually become part of a
mudflat or marsh soil, unless a large storm carries them out to sea. Gusty winds stir up
bottom sediments, aiding tidal currents in the redistribution process. In an estuary
experiencing large sediment inflows, flushing fine sediment out to sea can take decades.
San Francisco Bay, which has strong currents and winds, still retains much of the sediment
horn snail (Cerithidea brought in by streams after hydraulic gold mining in the 1870s flushed soil from the Sierra
Californica) Nevada foothills.

Besides removing and reshaping sediment within the estuary, the ocean moves the
sands making up the beach berm at the estuary entrance. Ocean currents and waves,
particularly large storm waves, move sand both along the San Diego coast, in a process
called littoral drift, and move sand on and off shore. A bucketful of sand dumped on the
beach in Carlsbad might be moved out into the shallow water one year and back onto the
beach the next, or it might be carried down the coast and become part of a beach in Del
Mar. Eventually this sand probably will disappear into the deep submarine canyon off La
Jolla and be forever lost to the coastal beaches. Along the southern San Diego coast, sand
moves from Mexico north toward Point Loma. Sand eroded from watersheds moves W
through estuaries into the ocean, constantly resupplying this system.
There is a continuous contest between the power of the ocean waves and the power of
the estuary's ebb tide to push the beach sand in and out of the estuary entrance. Large
storm waves can move sand into an estuary and partially block the entrance channel. As
the tide ebbs, the power of the outflowing water must be great enough to scour the channel
and clear the sand or the channel will close off. The volume of water that f lows into and out
of an estuary during a tidal cycle is termed the tidal prism. Of the two high tides that occur
each day, the higher one has a larger tidal prism and a greater ebb flow. The size of the tidal
prism varies according to each estuary's size and shape. Ocean currents and waves move
During a storm, when ocean waves are largest, an entrance channel may become sand along the coast in a process
blocked. At the same time, the estuary receives a large amount of fresh water. The water called littoral drift.
rises and eventually breaks a new channel through the weakest point in the beach berm.
Before highways, roads, and bridges were built on the coast, estuary entrance channels
were free to change location. The mouth of a lagoon could be on the north side of its beach
berm one year and have migrated to the south by the next summer. To maintain an open
channel, the inlet must be able to move in response to sand buildup.
Some estuaries, like Buena Vista Lagoon, never had a tidal prism large enough to scour
a new entrance channel. They probably closed off to the tides during summer, when runoff
was low, and ocean waves could overpower the small tidal ebb. But large estuaries such as
San Diego Bay and Batiquitos and San Elijo lagoons have large enough tidal prisms to
remain open year-round.

The development of the San Diego coast has interfered enormously with the function of Coastal Development
estuaries. Two or three roads now run through most coastal wetlands, built on landfill
with a small bridge across a channel to permit water outflow. Highway 1 constricts the inlet
of most of these estuaries and provides only a narrow bridge, thus stopping the migration
of the entrance channels. Once the mouth is confined to a fixed location, these estuaries
can no longer maintain an open channel. Now when ocean storm waves fill and block the
channel with sand, the estuary may remain closed until water levels are high enough to
scour the sand in that one location. In addition, many of San Diego's wetlands have been

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chopped into several separate bodies of water by fill and bridges for Interstate 5, El Camino
001fts*A,*1 Real, and the railroad. These constrictions slow water velocities and decrease the power of
the ebb flow to scour sand. As a result, many of San Diego's lagoons rarely open to the tide
anymore.
When an estuary's entrance channel closes, the movement of sediment out of the
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wetland stops. Much of the eroded sediment that flows into a closed estuary stays there,
filling in tidal areas and decreasing the size of the tidal prism. Direct filling of tidal areas for
development, as in San Dieguito Lagoon, further reduces the tidal prism. Agua Hedionda
Lagoon is the only lagoon with continuous tidal action because it was dredged in 1954 and
Top: Highway 101 and the rail- its mouth stabilized with jetties.
road dissect San Elijo Lagoon and One long-term effect of development along the San Diego coast is the loss of sandy
restrict its entrance channel to a beaches. Reservoirs now catch much of the sand eroded from watersheds, -stopping its
small opening. Bottom: Cobbles movement through streams to the ocean. Closed lagoons now collect the sand that once
fill the mouth of Batiquitos nourished the beaches. The overall result is an enormous decrease in the supply of sand to
Lagoon. Both lagoons rarely the beaches and the movement of what little sand remains down the coast and into the
open to tidal flows. submarine canyon. Cobbles now cover many beaches; ocean waves eat away coastal bluffs.

Riparian Forest

R
ivers and creeks follow twisted, curvy courses, in San Diego County occurs on the Santa Marga-
carving and re-depositing the sediment of the rita, San Luis Rey, Sweetwater, Otay, and San
watershed. The riparian forest, a tangle of willow, Diego rivers as well as many smaller streams.
sycamore, blackberry, nettle, and other plants, cre- Bird species such as the Least Bell's Vireo are now
ates a dense green lining along these streams. Until facing extinction due to riparian habitat loss.
recently, the modern urban landscape has had little Another often overlooked feature of riparian
use for these disorderly water courses. Civil engi- forest is its function in the movement of sediment
neers and land developers have straightened and in a watershed. Riparian plants have thick, tangled
"improved" many of our streams into narrow, deep, branches and root systems that slow water and
and sterile cement channels. The natural creek and collect sediment protecting downstream wetlands
river were removed in the name of flood control from filling in. Take out the trees and straighten the
and in an effort to dry out, fill in, and build on stream, and the sediment is carried directly into the
their floodplains. coastal wetland. The tree roots also bind together
What has our society lost in the effort to control the soft sediments of the channel banks, lending a
water flows and rearrange stream systems? The degree of protection from erosive urban storm
most obvious loss is beauty. A concrete channel flows. The clearing of riparian forest for agriculture
may be more efficient at moving water, but it cer- often opens the stream banks to undercutting
tainly lacks the beauty of a natural, green stream. and failure, sending the few extra acres of added
modems

Wildlife habitat is another loss. Ninety percent of crops downstream. "Improvement" of streams for
the riparian forest in California is gone; the major urban development removes their function as
river systems of Los Angeles and Orange counties sediment traps and protectors of downstream
are now mostly cement. Remaining riparian forest coastal wetlands.

Wetland Life

There would seem to be no real
hope for the future unless we
are prepared to accept the con-
cept that man, like all other
living things, is a part of one 4
great biological scheme. Today
almost every purpose and
activity of modern life takes
precedence over the one most
basic purpose of all, namely
that of conserving the living
resources of the earth.

Fairfield Osborn

M
uch of wetland life is hidden from human view, played out beneath the high tide or
in the rich mud of tidal flats. With each of its movements, the tide transforms the
wetland, giving the pulse of the ocean a solid, earthbound expression. For the resident
animals and plants, both large and microscopic, these pulses mark the routine of day and
night. With each high and low tide, different activities are underway. Bacteria crowd the
mud, absorbing and releasing different nutrients and organic compounds at each tidal
stage and recycling the basic elements. At low tide, mudflat dwellers lie hidden. High tide
brings food to these same creatures-worms, clams, shrimp, and other invertebrates.
Under the cover of water, small fish that hide in burrows at low tide, emerge to feed.
During the fall and winter months, flocks of migratory ducks and shorebirds arrive at
coastal wetlands. The rapid bobbing and dipping of these noisy flocks animate the shallow
water and exposed mudflats, lending a liveliness to the subtle landscape. By late spring the
flocks are gone, and the resident birds-herons, gulls, sparrows, and others- are left to
offer their own show. Nesting terns, floating pelicans, black cormorants, black-necked
stilts, and avocets also remain for the summer.
Most human interaction with wetlands has been by boat or boot for the purpose of
harvesting this richness of wildlife. Although we have relished the bounty of ducks, fish,
geese, crabs, and other animals the marshes support, most of us have remained ignorant
of the wetland's complex workings. The impenetrable mire of the mudflat and sulfulous
odor of low tide have deterred most visitors and set the image of "wastelands" into many
people's minds. Many coastal wetlands were "reclaimed" through dredge-and-fill projects
long before their value was recognized.
Scientists and naturalists only recently began detailed study of the life in San Diego
wetlands. Work at the Tijuana National Estuarine Research Reserve and San Diego State
University has been particularly important in painting a portrait of the wetland world.
Though we do not have a complete picture of this world, there are several aspects we can
explore. Among these are the dynamic nature of wetlands, the adaptation of wetland life to
environmental change, and the productivity of wetlands and their role in the international
migration of birds.

A Dynamic World
Coastal wetlands are a meeting of forces-the ocean pushing its tides and sand against the Cordgrass (Spartina foliosa)
land and the river or creek draining its fresh water and sediment into the sea. These two forces This plant, like many salt marsh
create everchanging conditions in the wetland. They not only bring fresh water and daily high species, has air spaces in its stems
and low tides, but they also produce floods, storm waves, and large sediment inflows. Such a and roots that allow it to with-
dynamic environment may seem too hostile to life. But plants and animals not only exist here, stand the lack of oxygen during
they thrive. long periods of tidal submergence.

Visit an estuary and salt marsh on the hottest day of August. The surrounding hills are
parched to a cardboard brown, and even the chaparral shrubs must go dormant to survive the
summer drought and heat. In stark contrast, the salt marsh, watered by the tide, is lush and
green. For the few plant species that have evolved the necessary adaptations, the saltwater
wetland provides ample sunshine and water. Other plant species cannot tolerate the physical
conditions here, especially the long periods of submergence in water and the high salinity
levels. Each wetland plant species tolerates a particular range of these two conditions.
With high tides submerging the marsh every twelve hours, soils remain waterlogged-a
situation similar to overwatering house plants. Marsh soils are often made up of clay and
drain very poorly. During yearly maximum tides, the plants of the lower marsh may be
submerged for 10 to 12 hours continuously. Only a few species have adapted to endure this
stressful situation. The average high tide will only briefly cover the high-elevation marsh,
wl-dch hes at about 2 1/2 feet above mean sea level. (Mean sea level is usually equated with the
0. 0-foot elevation on most maps). But the low-elevation marsh lying at mean sea level or below
is regularly covered by the high tide for hours at a time.
Soil salinity varies over the marsh surface. The lower marsh is continually bathed by the
tide; its soil salinity is close to that of seawater and does not vary much over the seasons. In the
middle and high marsh, soil salinities can vary greatly. Winter floods leach salts from the
higher elevations while summer drought concentrates salts, creating hypersahne soils. The
upper edges of the marsh are bathed in salt water only several times a year during extreme
high tides, yet their soils are saline enough to exclude most upland plants.
Different species inhabit the high and low marsh zones. Cordgrass grows by itself at the
lowest fringes of the marsh. Airspaces in its stems and roots enable it to withstand longer
periods of submergence than any of the other salt marsh species. A more diverse array of
plant species inhabits the upper marsh zone, with pickleweed often dominant. Other plants,
found in pockets of the higher marsh, include saltwort, annual pickleweed, jaumea, saltgrass,
alkali heath, and sea lavender. Each of these species can withstand only moderate levels of
submergence and has a specific tolerance range for soil salinity.
Among resident wetland animals, the most inconspicuous group is the invertebrates-
worms, snails, crabs, and mollusks. These animals inhabit the mudflats, muddy bottoms, and
sides of tidal channels, the soils beneath marsh plants, and often the plants themselves. For
Z the most part they are sedentary creatures, staying in a small area throughout their short lives.
Each species can endure a certain range of salinities, depth of water, temperature, period of
Z submergence and exposure, and type of substrate (sand versus clay). The sediments beneath
the deep, open water of San Diego Bay will support species of invertebrates that will differ
from those found in the intertidal mudflats, of the same estuary. More brackish areas of the
it
estuary near an inflowing river or creek present different conditions and may support
mvertebrate species not found in the tidal mudflat.

What's A Wetland?
77AI

Most coastal wetlands line estuaries. An estuary
is a semi-enclosed body of water that receives both
fresh water and seawater and includes the bays,
lagoons, and river and creek mouths of the coast.
Along the shores of these estuaries are salt and

and tidal channels. Freshwater marsh may border
brackish (somewhat salty) marshes, mudflats,

inflowing creeks. All constitute wetlands. The
lagoon or estuary itself may also be referred to as a
coastal wetland. Seasonally flooded pools or salt
pannes, closed lagoons and salt evaporator ponds
are also wetlands. So is the riparian forest-the
creek and river floodplains where trees and plants
grow. To avoid confusion, these stream-associated z
forests are referred to as riparian wetlands. < -

Unlike the sedentary invertebrates, fish can swim to areas within a wetland where
environmental conditions are favorable to them. Some small fish, such as the arrow goby or
the long-jawed mudsucker, reside in burrows in mudflats or channel banks. Turbot and
halibut are bottom fish whose larvae develop in the calm estuarine waters. Mullet, sandbass,
killifish, surfperch, and topsmelt are common in tidal channels and open water areas. The
enviroru-nental conditions most important to fish species include salinity levels, water tem-
peratures, the variety of habitat types, and abundance of food sources. Some chen-tical
components, such as the amount of oxygen dissolved in the water, are critically important to
the survival of fish.
Wetland plants and animals are specialists, adapted to particular places in the wetland.
These places are their habitat. Most plants and some animal species can live in only one
habitat, others need a variety. Several types of habitat can be identified in estuaries. Vegetation
type defines some-high or low marsh, brackish marsh, eelgrass beds; water character
defines other habitats-open water, intertidal mudflat and channels, subtidal bottom, and
salt panne. The more mobile animals-fish, birds, and mammals-may feed, nest, spawn, or
rest in different habitat types, and the variety of these habitats within a given estuary is
especially important.

Tidal salt marsh at Tijuana
Estuary

WARM

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Environmental Change
When the wetland environment changes, plants and animals must be able to withstand
the change or they die. Small or short-term variations, such as a winter flow of fresh water
into a tidal estuary, temporarily lower salinity levels and leach salts from soils. Most
estuarine plants, invertebrates, and fish can tolerate salinity levels lower than those of
seawater (34 parts per thousand), but not as low as pure fresh water (less than 1 part per
thousand). Cordgrass has adapted to changing salinity levels. Its seeds germinate best
when salinity levels are low, allowing the species to spread and grow rapidly following
major floods. The return to high salinity levels during summer may kill some of the new
plants, but many survive and the species expands its coverage.
Marsh vegetation continuously varies in response to everchanging physical conditions.
Researchers have studied the boundary between pickleweed and cordgrass over several
years at Tijuana Estuary, a tidal system with a large drainage basin. They found that this
boundary varies each year, with each species expanding or declining as conditions change
and give one plant species a greater advantage over others. Since pickleweed can with-
stand very high salinity levels, a long dry season or nontidal period might favor it while
causing cordgrass to die back because it is less tolerant of hypersaline conditions. Both
plants grow at slightly different elevations in the marsh. A slight change in elevation due to
ghost shrimp (Callianassa sediment deposition would favor pickleweed while scour would favor cordgrass. The
californicus) nature of wetlands is dynamic; static boundaries can rarely be applied.

Water releases from upstream reservoirs have caused major salinity changes in some Prolonged
coastal wetlands, with consequent damage to salt marsh vegetation and wildlife. Under Freshwater Flows
normal conditions, freshwater inflows occur in winter and are rare between May and
October. In the San Diego River flood control channel, for example, a well-developed tidal
marsh existed on the seaward end. Prolonged releases from an upstream reservoir in 1983
leached salt from soils and created freshwater conditions well into the summer. Later
studies by Dr. Joy Zedler of San Diego State University confirmed that the pickleweed was
smothered beneath a dense growth of freshwater tules. The pickleweed could not with-
stand the prolonged submersion created by the water releases, nor could it compete with
the freshwater marsh plants that invaded the area once salinity levels dropped. Even small
discharges of fresh water into wetlands during summer can change vegetation. For
example, at Los Pefiasquitos Lagoon, storm drains carrying small amounts of fresh water
from garden irrigation and roads have created a year-round source of fresh water and an
invasion of the salt marsh by cattails.

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Far left: Saltgrass (Distichlis
spicata) This plant species ex-
cretes salt through special glands
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n its stems and leaves. Left:
Pickleweed (Salicornia virginica)
This common salt marsh plant
eliminates excess salt by storing
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1W joints. These joints turn red in
>
-,Wf autumn and fall off, ridding the
plant of the salt.

Lagoon Closure When the mouth of an estuary or lagoon closes, environmental conditions change
greatly How wetland animals fare during a closure has been studied in detail at Tijuana
Estuary and at Los Pefiasquitos Lagoon.
Tijuana Estuary had been open to continuous tidal action for many years, but due to
high tides and large ocean waves in January 1984, the entrance channel became clogged
with sand. The following April, the mouth closed. Monitoring studies found that water
salinity levels soon after closing reached 60 parts per thousand (ppt) and that large areas of
the marsh dried out. The majority of the intertidal invertebrates and fish species died.
Eight months later, the mouth was dredged open, and the estuary returned to a tidal
condition. But studies by biologist Chris Nordby of San Diego State University for two
years after the dieback showed that the invertebrates and fish have not recovered. The
purple clam, one of the dominant invertebrates before the closing, has become extinct
from Tijuana Estuary. Fish have not returned in the variety of species that had occurred
previously.
Marsh plants were also affected. The dry, hypersaline conditions favored the growth of
pickleweed, but killed many cordgrass plants. Two other high-marsh species, annual
pickleweed and sea blite, were almost eliminated from the marsh following the closure.
Los Pefiasquitos Lagoon has been closed to regular tidal action for many years. It has
lost much of its tidal prism because of sedimentation and because the Highway 1 bridge has
Open tidal channel at Tijuana restricted its mouth. Since 1986, the mouth has been opened periodically with a bulldozer
Estuary. in an effort to enhance the lagoon. Studies have shown intertidal invertebrates and fish
invade on the incoming tide and become established in the marsh channels. However, the
lagoon mouth closes again a short time later, since the tidal prism is not great enough to
keep it open. Hypersaline conditions develop, but some of the fish and invertebrates are
able to survive. A fall or winter rainstorm will occur when the mouth is shut and cause a
sudden drop in salinity that kills most of the marine invertebrates and fish. This pattern of
colonization, closure, freshwater inflow, and dieoff has been documented for three years.
In both these wetlands, the chemical components of the water begin to change with the
closure of the entrance channel and loss of tidal flows. The impounded water evaporates,
leaving its salts behind, and creating a highly saline environment intolerable to many
wetland animals. Intertidal animals must "breathe" by taking in dissolved oxygen
through gills or skin. As the stagnant water heats up and the animals use up the oxygen,
they suffocate. A large influx of fresh water drastically changes salinity levels in the lagoon
killing many aquatic species. The conditions of the closed lagoon far exceed the tolerance
of many plants and resident animals. Before human disturbances along the coast, large
ocean waves may have closed San Diego's estuaries occasionally. But as the lagoons and
estuaries all had larger tidal prisms and unrestricted channels, it's likely that they readily
reopened. These large die-offs probably seldom occurred.

The closure of the mouth of
Tijuana Estuary in 1984 dried
out tidal sloughs and caused
a die-off of cordgrass marsh and
its inhabitant, the Light-footed
Clapper Rail.

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The gradual accumulation of sediment over years of average rainfall may go unnoticed, Sedimentation
but have pronounced effects on the wetland. Los Pefiasquitos Lagoon clearly shows these
effects. During five years of grading for housing developments just upstream, a delta at the
mouth of Carmel Valley Creek increased in height by 6 to 7 feet and smothered the
pickleweed marsh with sand. This new sediment lies above tide level and is not saline.
Riparian forest now grows in the new sediment, where previously salt marsh vegetation
had grown. The animal species using the riparian habitat will be completely different from
those in the salt marsh.
Following a large storm, large deposits of sediment will not only smother the animals
living in the estuary bottom, but also completely change the sediment type. The animals
that recolonize the new sediment will greatly differ from the previous inhabitants. For
example, the distribution of clam species in intertidal areas is related to the grain size of the
sediment. Purple clams prefer coarse sand, while littleneck clams inhabit areas of finer
sediment. California jackknife clams are found in medium to fine sand, and the white sand
@V-
clam mostly in medium-sized sand. If fine sediment from watershed erosion covers an
intertidal area, only the littleneck clams will recolonize the site previously inhabited by
four clam species. A larger inflow of sediment could change this clam bed into a flat
dominated by other invertebrate species, such as worms. If the amount of sediment is
extreme, or the inflow occurs during a mouth closure, the entire intertidal flat could be
filled in above high-tide level and become a marsh or even an upland.
Wetland plants and animals can survive many changes. They inhabit a waterborne
world where physical conditions vary with both the season and the time of day. But once
the environment changes beyond their tolerance levels, these species die, and the basic
character of the wetland is transformed. For many of San Diego's wetlands, this transfor- littleneck clam (Protothaca
mation has already occurred. starninea)

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The Edge Gets Thinner
When the Spanish traversed this land, they traveled far to the east of the coastline. Their
route was El Camino Real, which traces the upper border of many of San Diego's lagoons and
bays. They chose this route because the wetlands were major impediments to travel. Horses
and wagons could only cross at the far eastern end.
Most of San Diego's coastal wetlands are no longer tidal, and many have lost most of their
marshes and muciflats. Over the entire San Diego coastline, 75 percent of the wetlands are
gone. This loss has led to such dramatic population declines in several species that they now
face extinction. Although no one counted migratory birds in the 1800s, historic accounts give
the impression there were thousands more than we see today. Their numbers declined as the
mudflats, their favorite feeding area, were filled. Fish populations also have declined with the
@1'

loss of shallow tidal habitat.
Let us trace the changes in two of San Diego's wetlands-San Dieguito and Batiquitos
lagoons. Both have undergone drastic alterations causing declines in wildlife. We have chosen
these areas because they have each undergone a different form of loss. Despite changes,
thousands of migratory birds still depend on these areas. These wetlands are more valuable

Far left: San Dieguito Lagoon
as viewed from Crest Canyon in
1915. Arrow indicates current
location of 1-5. Left: The Del Mar
Fairgrounds was built on 200
acres of wetlands in San Dieguito
Lagoon.
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- nx_

than ever before because so few wetlands are left.
We know from archaeological and historic evidence that these wetlands were fully tidal
systems before European settlement. We do not have records of the amount of marsh,
mudflat, open water, or other wetland habitats that existed in the lagoons in the early 1800s.
The earliest maps date from 1887. However, since these were tidal estuaries, we can assume
that there was some salt marsh as well as other intertidal habitats in each lagoon.
San Dieguito Lagoon was the largest of San Diego's six lagoons. Its wetlands once stretched
inland well past the present-day Interstate 5 bridge. Historical maps and records indicate that
the lagoon mouth was open most of the time until the 1940s. Oyster beds and cordgrass marsh
occurred here-both dependent on regular tidal flushing. Between 1910 and 1975, the marsh
was filled to build roads and highways, a race track and fairgrounds, a shopping center, and a
military airfield. Upstream of Interstate 5, sedimentation has been extreme. Areas once
inundated by the tide are now 12 feet above sea level. Treated waste water was released into the
lagoon for over 20 years. Much of the freshwater flow in the San Dieguito River that reached
the lagoon was impounded with dams by the 1920s. By the early 1940s, the lagoon mouth was
closed most years. Since then, the value of the wetland habitat has steadily declined.

Overall, direct filling and sedimentation have destroyed more than half of this lagoon. The
lagoon has tidal habitat-high salt marsh, tidal channels, and mudflats-in its remaining
area. Along the east side of 1-5, many remnant "pieces" of salt marsh delineate the former
extent of tidewater. These pieces are now isolated from the main tidal channel and are quickly
changing to upland as adjacent lands are plowed for agriculture. A 1983 project funded by the
Conservancy and the City of Del Mar restored tidal flows to a 70-acre area. Overall, San
Dieguito Lagoon has been greatly reduced in size, leaving much less habitat for wetland
animals.
.Y, Batiquitos Lagoon, once a fully tidal system, no longer opens to tidal action. Sedimentation
has reduced its tidal prism to a fraction of its former size, and three road-fills block water
flows. The Highway 1 bridge constricts the lagoon mouth and plays a major role in keeping the
lagoon closed to the tides.
amphipods (Vibilia spp.) Stormwater now fills Batiquitos Lagoon during winter months. In dry years, water depths
may only reach several inches. In wet years, the lagoon may hold up to 12 feet of water.
Summer heat evaporates this water, concentrating salts remaining from the time the lagoon
was tidal. As the salts concentrate, the remaining water becomes hypersaline and sometimes
reaches over 60 ppt salt, almost twice the salt concentration in seawater. During dry years, the
lagoon waters shrink or disappear completely.
Batiquitos Lagoon now has a highly variable water regime that changes the types of
habitats available from year to year. A narrow fringe of salt and brackish marsh covers the
edge of the lagoon. Winter submergence with fresh or brackish water favors brackish and
freshwater species, while hypersaline and dry summer conditions will favor certain salt
marsh plants. The marsh may change dramatically as the annual water regime varies.

Igo'
Nummorm-

Batiquitos Lagoon is now closed
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to tidal flows. @*'@ Rkik
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Batiquitos Lagoon in 1898. The
constriction of the mouth by the
railroad already caused frequent
closures. Marsh once extended
east of El Camino Real.

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Some recent sampling found very few invertebrate species inhabiting the lagoon bottom.
Three insect species, one species of ostracod (a microscopic crustacean), and one snail species
made up the majority of the organisms found. The most plentiful invertebrate was a small
aquatic insect, the water boatman. The lagoon supports huge blooms of these highly mobile
insects, which feed on algae and other detrital material, and are able to withstand a very wide
range of salinities. For migratory birds, these insect blooms are a major source of food, but
they are only available when water levels are shallow. Deep water excludes most shorebirds
and dabbling ducks from feeding.
Although it is no longer tidal, Batiquitos Lagoon supports several thousand migratory
shorebirds and ducks when water levels are low. The birds have adapted to feeding on the
insects and ostracods now present rather than the mudflat invertebrates more common in a
tidal lagoon. Most fish and invertebrate species cannot survive in the lagoon and appear to
have been lost from this wetland. Sedimentation continues to fill the lagoon at a rate that could
turn it into an upland in less than 50 years.
Most of these wetland losses are permanent. In the case of San Dieguito Lagoon, the
habitat that remains is healthier than it was ten years ago, but only as a result of a million-
dollar restoration project. Another major restoration project is planned for Batiquitos Lagoon.
Numerous laws now regulate the filling of coastal wetlands. But have these efforts gone far
enough? Will our remaining wetlands disappear as well? The next section reviews the current water boatman (Trichocorixa
problems our wetlands face. reticulata)

Endangered Species:
The Homeless of the Animal World

The California Least Tern once had the beach to
itself and nested in large, noisy colonies on the up-
per beach sands and dunes. Terns hunt small fish
When I hear of the destruction of a species I feel as if all in nearby estuaries and migrate south for the win-
the works of some great writer had perished. ter. Since the beaches of Southern California have
become famous for sunbathers and surfers, the
terns have had to look elsewhere for nesting spots.
- Theodore Roosevelt They have not located many, and their numbers
have steadily declined. When they do nest, they
are often disturbed by dogs or other predators and
lose their eggs or hatchlings. The least tern is offi-
cially listed as a federal and state endangered
A
long most of the Southern California coast, species.
marinas, houses, harbors, and roads have re-
placed vast estuaries and wetlands. The few pieces
of marsh remaining are often in poor condition,
surrounded by development or cut off from tidal
flows. For the animals that depend on marshes and
estuaries, this loss of habitat has been devastating.
Drastic population declines have accompanied hu.-
man expansion on the coast, creating "endangered
species" whose existence is in peril. Six bird species
and one plant species are now so diminished in
number that any further reductions could cause
their extinction. The federal and state Endangered
Species acts provide a measure of protection to
these plants and animals. Preservation of their hab-
0
itat is the key to stopping their decline. Each time X
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more nesting or feeding habitat is lost or human W
disturbance is increased, the survival of these
species is threatened.

The Light-footed Clapper Rail is a resident of The Snowy Plover is a small shorebird that once
the salt marsh. It lives year-round in the dense nested on open beaches and dunes. Like the tern,
cover of cordgrass, feeding on invertebrates, larval it has had a hard time finding nesting spots. It has
fish, and vegetation. The platform nest it builds in resorted to using salt flats, levees that surround
the marsh rises during high tide, but does not float salt ponds, and old fill sites. When disturbed by
away because the tall grass holds it in place. Now humans, pets, or predators, the
few healthy stands of tidal cordgrass marsh re- plover often cannot manage to
main, and these only occur in consistently tidal raise its young. The Snowy
estuaries. Los Pefiasquitos Lagoon once supported Plover is a candidate for
this species. The current non-tidal condition of the federal endangered
lagoon does not favor the survival of either cord- species status.
grass or the clapper rail. The Light-footed Clapper
Rail is found only in Southern California salt
marshes and is listed by the state and federal
governments as an endangered species.

Also endangered is the Belding's Savannah
Sparrow, a small songbird that lives and
nests in the pickleweed marsh
and has adapted to drinking
seawater. It eats insects, seeds,
and some vegetation. When
nesting, sparrows are sensitive
to disturbance and have been
known to desert their nests if
their egg-laying cycle is inter-
j rupted. The sparrow has suffered
population declines with the loss
ot suitable high pickleweed marsh.
The state has recognized it as an
endangered species.

to pesticide pollution, particularly DDT, which has
concentrated in the food chain and caused a thin-
ning in bird eggshells. When a parent sits on its
egg, the egg breaks. Since the banning of DDT in
the 1970s, the pelican has made a comeback, but
still relies on estuaries as a source of fish and a
roosting area. The pelican
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is a state and federally
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species.

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The Least Bell's Vireo is a small migratory song-
bird of riparian wetlands. Since riparian forest has
suffered nearly the same level of destruction as salt
marsh wetlands in Southern California, this bird
must struggle to find appropriate nesting sites. It The Salt Marsh Bird's Beak (Cordylanthus mar-
must also contend with nest parasitism by the itimus maritimus) is an endangered plant of the high
Brown-headed Cowbird, a species that frequents salt marsh zone. It is an annual, germinating in
agricultural lands. As agriculture has spread to the spring and parasitizing other
edge of riparian lands, the cowbird has increased in marsh plants to survive the
numbers. Its reproductive strategy involves laying summer and then dying
eggs in the nests of other birds such as the vireo. back. Both loss of marsh
The cowbird chicks then outcompete the vireo areas and human distur-
chicks, and the vireo parents raise young of the bance to marshes have
wrong species. The vireo is a state and federally severely reduced popu-
listed endangered species. lations of this plant. Salt
Mar
kl@ sh Bird's Beak is a feder-
The Brown Pelican feeds and rests on the open ally listed endangered species.
water of bays and estuaries. It makes spectacular
head-first dives into the water to catch fish. The de-
cline in pelican populations is directly attributable

- - - - - - - - - - - - - - -......

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. . . . . . . . . . . . .
........... . . . . .
Wetland birds come in all shapes and sizes, from
Migration small sandpipers to terns to dabbling ducks. Most
are highly specialized to catch and eat only particu-
E
ach year millions of birds, fish, and mammals lar animals. Shorebirds, for instance, each have a
thrive in coastal wetlands. Birds are most con- different bill shape and leg length. A short-legged
spicuous among the wetland inhabitants. The bird with a small bill pokes in the mud surface for
yearly arrival of flocks of shorebirds and waterfowl small worms and crustaceans. Longer beaks probe
signals both the end of summer and the renewal of deeper, curved beaks scoop through the mud sur-
a timeless pattern of movement. The migratory fly- face, thick beaks crack shells. One species, the
way along the Pacific coast has linked San Diego to Northern Phalarope, turns in circles to stir up in-
the Arctic and parts of the Northern Great Plains sect larvae and small crustaceans from the muddy
for centuries. Millions of shorebirds nest on,the wet bottom and then snatches them out of the water. It
tundra of Alaska and Canada, exploiting the pTofu- contrast, a Forster's Tern dives into the open water
sion of insects, invertebrates, and fish of the arctic to grab small fish, while herons and egrets stand
summer. Many duck species nest in the prairie pot- motionless, then suddenly stab a fish. Dabbling
hole wetlands of the Great Plains. After fledging ducks flip end-up to graze on snails, crustaceans,
their young, these flocks return south, stopping at and vegetation in shallow water. Diving ducks,
the bays and estuaries of the Pacific coast or at inte- grebes, cormorants, and others swim underwater
rior freshwater wetlands. Each wetland is a link in in pursuit of small fish. Each bird species feeds on
a chain of feeding stations where the birds must particular types of animals-worms, clams, crabs,
find adequate food to survive the winter season. shrimp, crustaceans, marsh insects, or small fish.

CORIDGRASS PICKLEWEED

High Tide

CRAB
HORN SNAILS...-...., -

... ... .......
....... .......
MU
. ........ .... .. GHOST SHRIMP

................
.........
BENT NOSE CLAM

... . ................
WORMS
CALIFORNIA JACKNIFE CLAM
GAPER CLAM

ARROW GOBY
EELGRASS

FAT INNKEEPER

Each wetland contains an assemblage of habitats,
each of which provides different invertebrates and
fish for certain bird species. Mudflats, for instance,
th
are a smorgasbord of different animals. Surface
15.1
dwellers like horn snails and amphipods graze the
thin layer of algae covering the mud. Crabs venture
out of their mudflat burrows to search for bits of
food during low tide. But most mudflat residents
are hidden, residing from barely beneath the sur-
face to several inches down. They include worms
of many sizes, shrimp, several types of clams, and
other mollusks. Each invertebrate filters copious
amounts of tidal water, and sometimes mud as JI;
well, to sieve out bits of food. Large and small
shorebirds poke and probe for different inverte-
brates. The bill of each bird species reaches a
different level in the mud and sucks out a different
type of invertebrate. rock crab (Pachygrapsus crassipes)

San Diego

Z.nig.
J.Iy San
Z Diego
Pacific Bay
Ocean

[email protected]*111 0 12 3

ed in San Diego Bay
Wetlands fill
A large flock of birds overwintering in an estu- This web of interaction is intricate and vulner-
ary attests to the enormous productivity of wetland able. Loss at one level-such as an invertebrate
systems. The photosynthetic material of the plant population wiped out by a sewage spill affects all of
cell turns sunlight into sugar and creates food. the higher levels. Many of the migratory bird flocks
Studies at Tijuana Estuary by Joy Zedler found that along the Pacific Flyway depend upon the health of
the mats of algae which carpet the open spaces in San Diego wetlands. Each coastal wetland is both a
the marsh contributed a very large percentage of local asset and an international resource. With over
the primary production of the estuary. These algae 75 percent of California's coastal wetlands already
and the marsh plants form the base of the wetland gone, the loss of even one wetland in the chain
food web. This plant material finds its way into the strains the remaining links and forces bird popula-
animal world in several ways. Snails, crabs, larval tions to depend on an even smaller food supply.
fish, amphipods, and other invertebrates graze the On the San Diego coast many researchers believe
algal mats. Bacteria and fungi break down dead that the birds make use of different coastal wet-
plant parts and algal cells. into bits of detritus. Tidat lands during the winter, depending on which one
waters circulate a soup of detritus and free-floating has the right conditions to produce a large food
algae, called plankton, through marsh channels base. Since each wetland varies in the types of hab-
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and over mudflats, bringing food to worms, clams, itat it contains, different species will concentrate in
small fish, crabs, and other animals. These small different lagoons or bays, making each wetland and
animals in turn are eaten by larger fish and birds. its continued health an essential factor in the sur-
Even larger predators hunt these birds and fish. vival of these birds.

Preserving What's Left

Going back to California is not
like going back to Vermont, or U
Chicago; Vermont and Chicago
are relative constants against
which one measures Otte's own
change. All that is constant
about the California of my
childhood is the rate at which
z
it disappears. F.:
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Joan Didion
z

E
ach year, half a million more people move to California from other states and abroad,
and many of them settle in San Diego County. To accommodate this enormous
population growth, subdivisions, industrial parks, shopping centers, and freeways are
hastily being built, especially near the coast. For coastal wetlands, this development
means rising sedimentation rates from eroding watersheds, raw sewage spilling into
lagoons from overloaded sewer lines, and pressures to fill remaining wetlands as coastal
land prices soar. San Diego's largest wetland, Tijuana Estuary, is now on the verge of
ecological collapse caused by sewage inflows and sedimentation. Many of the county's
lagoons could fill with sediment in the next 30 to 50 years.
Theoretically, the wetlands are now protected by law and government regulations.
Several state and federal agencies regulate filling and dredging through permit authority.
Other state and federal agencies work to preserve remnant natural wetlands and restore
the health of degraded wetlands. But can these public efforts suffice to ensure our
wetlands' survival? There are strong indications that the answer is no.
Even when the laws and regulations are diligently implemented and fully complied
with they offer insufficient protection. Coastal wetlands can only be protected within the
context of their entire system-both watershed and tidal entrance channel. Coastal devel-
opments and highways block beaches and stop tidal inflows to wetlands. Projects up
stream have major impacts on coastal wetlands. But jurisdictional lines fail to provide for a
broad enough view. Unless local governments assure that developments throughout each
watershed are planned with consideration of their downstream effects, wetlands will silt
Western Sandpiper up, lose their tidal flow, and require repeated costly restoration at public expense.

Wetland Preservation and Restoration: A Public Investment
In the 1970s and 1980s considerable acreage of coastal wetlands was bought and preserved.
State and federal agencies, and private conservation groups spent millions of dollars in San
Diego County to purchase wetlands and create a series of reserves and refuges. As a result,
most of the north county lagoons as well as parts of Mission Bay, San Diego Bay, and most of
Tijuana Estuary are now publicly owned.
However, to preserve these areas as wetlands it is not enough to own them or to regulate
filling or dredging them. Almost all of these wetlands suffer from extremely high sedimenta-
tiOn rates due to upstream development that is completed without adequate erosion control
measures or stormwater planning. Local governments typically regulate land grading in
watersheds and rarely have an adequate erosion control ordinance. Additionally, few inland
local governments even recognize a need for strict erosion control and allow such destructive
practices as land grading in winter rains, and clearing and grading of stream channels. The
typical reason given for not requiring better land development practices is economic-
additional requirements burden the developer. However, this reasoning disregards the fact
that these developments create a growing need for expensive restoration projects to maintain
downstream wetlands. Without any restoration, sedimentation will change these public
reserves into uplands.
Wetland restoration projects may remove not only sediment, but also structures; they may
restore tidal or freshwater flows, re-create particular habitats, or enhance the productivity of
the wetland. There are restoration programs currently underway or being planned for nearly
all of San Diego's publicly owned wetlands. In most instances the restoration is required to
remove accumulated sediment or to restore tidal flows. Most of these will be financed by large
sums of voter-approved bond funds administered by the Coastal Conservancy and several
other agencies or by other public funds.
Restoration projects represent a hopeful trend for coastal wetlands. They are complex,
require detailed and thoughtful planning, and are often expensive. In most cases the wetland,
criss-crossed by road fills, cannot be restored to its original state. Instead its value to wildlife
can be enhanced, and it can be carefully managed to avoid further damage from its urban
neighbors. Several restoration projects have occurred in San Diego.
A portion of San Dieguito Lagoon was restored in 1983 to remove accumulated sediment UO
and re-create tidal habitats. The southwestern corner of the lagoon, called the "fish hook," was
smothered by an avalanche of sand in the early 1980s. A subdivision on the bluff above the
lagoon had a poorly designed stormdrain system, which released large volumes of stormwa-
ter into Crest Canyon, a local city park. After several large storms, Crest Canyon became a
deep gully, sending tons of sediment directly into the lagoon. U
In 1983 the Coastal Conservancy granted $1.3 million to the City of Del Mar to dredge this
sediment out of a 70-acre area and to create a tidal basin with mudflats. The dredging Go
generally followed a plan for this lagoon that the Conservancy, City of Del Mar, and local

citizens had developed in 1978. The dredge spoils were placed back into the gullied canyon
and planted over with native trees and shrubs. The City of San Diego, using over $300,000 of
its own funds, installed new underground stormwater pipes through Crest Canyon and
corrected the original problem. The lagoon mouth was bulldozed open, and tidal flows were
restored to the lagoon and reached up the river channel to El Camino Real.
The newly dredged tidal basin sprang back to life. Monitoring studies found that fish and
U
0 invertebrates quickly invaded and multiplied, bird life increased in numbers and diversity,
and endangered species started visiting the area. The project is generally regarded as
0
U successful. By removing sediment and restoring tidal flushing, it restored habitat that had
Z
0 been lost from the lagoon. The project was completely funded by public money The 107-acre
reserve is owned by the Department of Fish and Game. Volunteers from local nonprofit
A bulldozer clears the entrance groups monitor the wildlife of the reserve.
channel of Los Pefiasquitos Another promising enhancement project is underway in Buena Vista Lagoon. It is espe-
Lagoon. The Los Peftasquitos cially interesting because it addresses the cause of sedimentation in the wetland by restoring
Lagoon Foundation has been the watershed. Buena Vista Lagoon is an impounded freshwater lagoon that has filled in
carrying out a program of considerably. Large urban stormwater flows are eroding Buena Vista Creek. As development
opening and monitoring the of the watershed continues, this problem increases, and the long-term prognosis for the
lagoon since 1986. lagoon is not good. Without either continued dredging of the lagoon at a cost of $2 minion
every few years or watershed restoration, the lagoon could completely fill in within 20 years.
The Conservancy, working with the three cities in the watershed, the Buena Vista Lagoon
Foundation, and the lagoon's owner, the Department of Fish and Game, completed a
watershed erosion control plan in 1985. The plan called for strict erosion control measures in
the three cities and for retrofitting the upper watershed to restore its hydrologic balance. In
1987 the Conservancy granted $850,000 to the City of Vista to construct a large stormwater
detention basin to lower the peak volume and the erosive force of stormwater, and to design a
creek channel with riparian vegetation and drop structures to slow water velocities and curb
erosion of the channel. Another $1 million or more will be needed to completely restore the
watershed.
Wetland restoration is a science in its infancy and is often considered more of an art form by
its practitioners. But with careful steps, detailed study, and large amounts of funds, restora-
tion can perhaps undo past degradation and return many of San Diego's coastal wetlands to a
healthier state.
But undoing past problems will not be enough. Projects like those at San Dieguito and
Buena Vista lagoons are only the beginning of what will be needed to maintain coastal
wetlands as their watersheds are being developed. The effects of this watershed disturbance
may not be seen for decades-until a great storm hits. We are left with a choice between
reducing this disturbance now through strict local control of development practices or by
spending millions of dollars of public money to restore the damage later. Our grandchildren
may wish we had made a better choice.

How You Can Help and other documents are available at the city or
county offices or at a local library
As a resident of San Diego County, you can make Speak out for wetland and watershed protection
a difference in preserving coastal wetlands. The to your elected officials. Let them know that wet-
following list suggests ways to get involved. lands have a vocal constituency.
Get to know your wetlands. This booklet includes A local nonprofit group can work to revise erosion
a listing of public trails and nature centers for each control ordinances to reflect the rules used in the
wetland. Experience the serenity of a lagoon or coastal zone. These rules were designed to protect
marsh or sneak a peek at some shorebirds. Maybe wetlands.
you'll see an endangered animal. The local group or individual can visit develop-
join one of the many nonprofit organizations ment sites plan in hand and see if the practices
associated with San Diego's wetlands and listed in being used are those required. Call the local build-
this booklet. These groups work in varied ways to ing inspectors to report violations. One local
preserve wetlands, monitor wildlife, and educate nonprofit, the Buena Vista Lagoon Foundation,
the public. established an erosion hotline to report violations.
Contribute funds to nonprofits that are actively Local governments in a watershed can work coop-
working to protect wetlands. Most of the groups eratively by forming a joint powers authority to
listed are designated as charitable organizations by address erosion problems. The Conservancy can
the IRS, and your contributions are tax exempt. assist in forming these groups and in funding
Volunteer as a docent at one of the nature centers. watershed erosion control plans for most wetlands.
Contact the centers for more information.
Volunteer to patrol San Elijo Lagoon to stop trash
dumping and other destructive practices. You could
organize a similar squad for your local lagoon to
eliminate dumping and abuse.
Volunteer to monitor bird species through one of
the Audubon Society's bird walks. You will need to gild
learn to identify bird species well and to use a pair
of binoculars. Contact either of the local, Audubon
chapters.
Initiate a wetland restoration plan if your favorite
wetland lacks one. The Conservancy can assist in
funding certain plans.
Become involved in local government actions that
affect coastal wetlands. You can request to receive N
the agenda of city council and county supervisors
meetings. Copies of development proposals, EIRs, Mudflat in lower San Diego River channel

Nonprofits can petition local governments to re- 0 Is the project sponsor providing long-term
vise their policies regarding creeks and zone them monitoring, maintenance, and, if necessary,
as open space or conservation areas. A policy of alteration of the mitigation site to achieve a
retaining natural vegetated creek channels should functioning wetland, not just a specified acreage
be adopted. of wetland plants?
Review proposed projects and plans to see if the Developments Near Wetlands
following questions are adequately addressed. Rec- Projects that directly border lagoons, marshes, and
ommend that the responsible government agency creeks can cause the greatest amounts of both sedi-
address all these questions in their environmental mentation and disturbance. The local government
review: and sometimes the Coastal Commission will have
Wetland Filling or Dredging permit authority. They should consider the follow-
Recent studies by Joy Zedler of San Diego State ing questions:
University compared a man-made mitigation marsh 0 Is there an adequate buffer (a minimum of
with a nearby natural marsh in an evaluation of a 100 feet, but the larger the better) between the
wetland fill project for a highway expansion at the development and the wetland?
Sweetwater Marsh. The research found that the 0 Is the development designed so that noisy,
mitigation marsh does not function as a natural
marsh and does not provide the habitat it was
designed to compensate for. Mitigation is a widely
applied concept based on the assumption that
man-made wetlands function the same as natural
wetlands. This research, the first of its kind, seems
to prove this assumption to be false and points to
a need to preserve existing wetlands and relocate
projects out of wetlands to upland areas. Typically
the U.S. Army Corps of Engineers and California
Coastal Commission have the primary permit
authority over filling and dredging in coastal wet-
lands. The most pertinent questions to ask:
'Yp
Is fill absolutely necessary or can the project
j%i
be relocated or designed to avoid wetland losses?
0 Is mitigation proposed to compensate for the
fill? If so, is the mitigation nearby and of the
same habitat type?
Are endangered species using the proposed X
fill site, and how can their use of the mitigation
site be assured?

intense activities are located away from the 0 Are there provisions that the project sponsor
wetland to protect wildlife? perform long-term maintenance of sediment
0 Is there a provision for fencing to protect basins and other structures?
wetland wildlife from domestic pets?
9 Are erosion control measures adequate to Creek Improvements The goal should be to retain
avoid silting up the wetland? natural vegetated creeks that do not increase the
Watershed Developments velocity of stormflows and cause downstream ero-
In most cases the local government has direct per- sion. In addition to local government jurisdiction,
mit authority over all subdivisions, commercial and the Department of Fish and Game and Army Corps
industrial developments in upland areas. Large pro- of Engineers probably have permit authority over
jects typically require an EIR that should address the creek.
all of the following questions and determine if the 0 Does the project alter creeks on the site?
project will significantly affect downstream wet- 0 Is there a provision for vegetated channels
lands. There are three primary types of problems that retain natural or replanted riparian habitat?
caused by watershed developments-increased * Is there a provision that the new creek chan-
erosion, loss of natural creeks, and increased nel not increase the velocity of stormwaters in
stormwater flows. excess of 6 feet per second for the 100-year flood
Erosion Control The goal should be for the project and not cause erosion of creeks downstream?
to have no detrimental effects on water quality
downstream, by retaining all disturbed soil on the Stormwater Management Most developments are
grading site with no movement onto adjacent designed with the notion of moving stormwater off
streets or down creeks and stormdrains. the site quickly with little regard for its effect on
0 Does the project use the minimum of grading downstream creek channels or canyons. Most local
and limit grading on steep slopes? cities and counties have master drainage plans that
0 Is there a requirement for the project sponsor are periodically updated and should address the
to post a performance bond with the local overall effect of watershed development and storm-
government to ensure that grading is done water on creeks and wetlands.
correctly? 0 Does the project provide that peak stormflows
0 Is grading prohibited during the winter rainy leaving the site shall not increase over the flows
season, October 15-March 15? It is very impor- that occur without the project?
tant that this be required. * Does the project employ stormwater detention
0 Are sediment basins, straw bales, or other basins or other measures on-site to hold peak
erosion control measures required? stormflows and release them at a slow rate?
0 Are there provisions that the project sponsor * Are the release points of stormdrains ade-
have slopes stabilized and revegetated prior to quately protected, or will they create gullies that
October 15? silt up wetlands?

Inventory of
San Diego N
Coastal Wetlands NOT TO SCALE

T
his map depicts the coastal wetlands and water-
sheds of San Diego County. We have made an
effort to delineate most tributary streams within
each watershed, but may have missed a few creeks.
The map illustrates how large a land area drains
into each coastal wetland and affects its functions V.
and its wildlife. z
The inventory which follows describes the his-
tory, natural resources, problems and public access U)
opportunities for San Diego's eleven largest coastal FALLBROOK M
wetlands. Many smaller creeks and wetlands dot
the northern area of the coast. These small creeks
provide habitat for migratory birds, fish and several
endangered species. Beginning at the northern end
of the county these include - San Mateo Creek VISTA
(marsh-30 acres, 132 square mile watershed); San
Onofre Creek (marsh-2 acres, 30 square mile water-
shed); Las Flores Creek (lagoon-10 acres, freshwater
OCEANSI
marsh-60 acres, 20 square mile watershed); French
Canyon (lagoon-10 acres, 5 square mile watershed);
Little Cocklebur Creek (marsh-3 acres, 5 square 0
mile watershed); Loma Alta Slough (lagoon-8 acres,
20 square mile watershed). All but two of these
A
9
areas are closed to the public due to their location
.:.:::::.Santa Mar
on Camp Pendleton. San Mateo Marsh is managed
by San Onofre State Beach. Loma Alta Slough, lo-
cated in Buccaneer Beach Park in Oceanside, is an
:..-:.-:,.San Luis Rey River
eight acre remanant of an original 40-acre wetland.

Lake Henshaw
Lake@@
Sutherland
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hasqultos::: :.::.,...San Diego
.......... ..
Lagoon
..........
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Hedionda Lagoon ..,-CORONADO...
Mission Bay:,--.-.-1.
T" na Estuary.-:::::::::::,:::::::::
qua
.. .. ... .. ... . ........ .
oow.@:@i@@@@@ an Elijo Lagoon......... osaSloughil
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VV,V

Santa Margarita River and Estuary

Location and Size Land Ownership
Estuary-Camp Pendleton Marine Base, 268 The U.S. Marine Corps owns the entire Santa
acres. Watershed-Camp Pendleton Marine Base, Margarita Estuary, the lower watershed, and the
San Diego and Riverside counties, 740 square lower 17 miles of the river. The Marines manage the
miles. estuary as a natural preserve.
History Wildlife Values
The Santa Margarita River is the least disturbed The Santa Margarita Estuary provides several
river system on the Southern California coast. The types of habitat for wetland wildlife and is well
lower 1.7 miles of the river channel floods with protected from human disturbance. Currently,
tidewater, making it an estuary the estuary west of Interstate 5 covers 268 acres,
The earliest aerial photographs date from 1928 including 95 acres of salt marsh, 35 acres of open
and 1938 and show about 370 acres of tidal channels water, 7 acres of mudflat, 6 acres- of brackish marsh,
and marsh in the estuary extending south nearly to and 125 acres of salt flats. Monitoring studies of the
the present location of the Oceanside Harbor. In aquatic life in the estuary in 1987 found 16 species
these same photographs, the estuary of the San of invertebrates, including mollusks, tube worms,
Luis Rey River extends far northward from its pre- crabs, horn snails, and 16 species of fish. Numerous
sent mouth. Only a narrow strip of land separated waterfowl, terns, gulls, and some shorebirds use
the two estuaries, giving the Oceanside coastline the estuary as well.
an almost continuous border of wetlands. The Santa Margarita Estuary has a large number
In 1942 Camp Pendleton was established and the of threatened or endangered species, including the
Del Mar Boat Basin was carved out of 153 acres of largest concentration of nesting least terns in the
the southern Santa Margarita Estuary. Until 1970, world. The Marine Corps has constructed a one-
the Marines used the salt flats of the estuary for acre tern nesting island in the salt flat area. The
tank training exercises. Amphibious personnel terns also nest on the beach berm. Their colonies
carriers practiced landing along the estuary beach are fenced off each year for protection. The estuary
berm. During this same period, wastewater was also supports clapper rails in its brackish areas, sa-
discharged directly into the estuary. These practices vannah sparrows in its pickleweed marsh, brown
were stopped in the early 1970s. pelicans on its open water, and tidewater gobies in
Three enhancement projects have improved the its brackish waters. The goby is a very small fish
habitat for wildlife. In 1965 the river channel was found in only a few streams in Southern California
dredged deeper for waterfowl. Six years later, the and is a candidate for endangered species status.
brackish marsh along the north side of the estuary The Santa Margarita River contains the most
was dredged, transforming it into a salt marsh. In extensive corridor of riparian habitat in the county.
1985 a one-acre least tern nesting island was con- The largest remaining population of Least Bell's
structed in the estuary. vireos occurs on this river.system. The riparian
40

habitat here is of particularly high quality because
the Santa Margarita is one of the last rivers in the
county unimpeded by large dams. Therefore it still
floods, periodically scouring and changing the '40
floodplain. The habitat can then regrow and
contains scour pools, freshwater marsh, young WE Wal
WTI',
understory trees and herbs, and large older trees
that survive the floods.

Current Problems
Before the 1940s, the estuary mouth remained
open year-round, but following 1941, it began to
close periodically. Although the estuary had lost a -7
portion of its tidal prism, the cause of the mouth im" _T_
closures may be related to developments down-
coast. The building of the breakwater at Oceanside @5
Harbor has blocked the southerly movement of
sand and caused a buildup of sand along the Santa
Margarita estuary channel. This abnormally large
sand buildup makes a formidable barrier for the es- Bell's Vireo habitat. The Marine Corps no longer
tuary's ebb tide, and it cannot consistently clear the supports damming the river. However, the Fall-
channel. brook Public Utilities District continues to pursue
The Marines plan a major enhancement project its proposal.
for the Santa Margarita Estuary. The main river In Riverside County near Temecula some large
channel will be dredged and deepened from the land development projects are being planned. The
highway bridge to the ocean, and a second least land grading envisioned for these projects could
tern island created. Several smaller channels would cause a great deal of sedimentation into the river
be dredged north of the main channel to improve and estuary.
the habitat for clapper rail. It isn't clear yet if these Public Access
improvements will allow the estuary to maintain an
open channel. Camp Pendleton owns and manages the Santa
The Santa Margarita River is the longest free- Margarita Estuary for protection of its natural
flowing river in coastal Southern California. Two resources. Public access is not allowed without spe-
small dams impound tributary streams, but 27 cific written permission of the commanding general
miles of the main river are undammed. The town and then only for scientific research purposes.
of Fallbrook has been attempting to build a dam on The Friends of the Santa Margarita River is a
the Santa Margarita River since the 1960s, but has nonprofit membership organization that provides
met with great opposition from local conservation- information about the river and the estuary.
ists. Such a dam would affect large areas of Least Contact: RO. Box 923, Fallbrook, CA 92028.

San Luis Rey River

export to Carlsbad and Oceanside. Logs of wells in
the area show a continuous drop in groundwater
level, reaching an extreme low point in the early
Z 1960s. On and river floodplains like the San Luis
Rey, riparian trees need groundwater to survive
the long, dry summer. All this pumping led to the
intrusion of seawater into the mission groundwater
basin. To alleviate this problem, the City of Ocean-
side discharged treated wastewater into the San
U
Luis Rey River from 1958 to 1974. Additional irriga
e
tion water was also released. Following these
< Al@
actions both groundwater levels and riparian
vegetation increas&d.
1936 Location and Size The estuary at the mouth of the San Luis Rey
was dredged in 1964 to create the Oceanside Har-
Lagoon-City of Oceanside, 40 acres. bor, primarily for recreational boats. A road now
Watershed-City of Oceanside and San Diego crosses the beach berm at the mouth, further
County, 558 square miles. restricting tidal flows.
History Land Ownership
The San Luis Rey River once flowed into a 100- The City of Oceanside owns Oceanside Harbor
acre estuary before reaching the sea. Both the 1888 and the lower river channel from the railroad to the
and 1898 maps of the San Luis Rey River indicate beach. The vast majority of the San Luis Rey River
the river valley was filled with wetlands. Marsh floodplain is privately owned. The City of Ocean-
was indicated from bluff to bluff and filled most side, in constructing its flood control project, will
side canyons. These early maps do not differentiate need to purchase the lower seven miles of river
types of wetlands, but it is likely that the floodplain floodplain.
above the current location of Interstate 5 was fresh- Wildlife Values
water marsh and riparian forest.
European settlement of the area, beginning with The primary wildlife values on the San Luis Rey
the establishment of the Mission San Luis Rey de River are associated with riparian habitat and the
Francia in 1798, brought reclamation of floodplain small marsh area at the river mouth. This area
wetlands for agriculture. In the mission subbasin, contains brackish marsh and supports a few shore-
which encompasses the lower 11 miles of the river birds, waterfowl, and water birds. Brown pelicans
valley, water was pumped for agriculture and for and least terns feed and roost in the lagoon.

Riparian habitat covers nearly 1700 acres of the fill projects and losses of riparian habitat. The
San Luis Rey River floodplain from 1-5 inland to primary permitting agency, the Army Corps of
Lake Henshaw. The densest areas of riparian forest Engineers, has been unsuccessful at enforcing the
occur in the lower river valley, along Pilgrim Creek, regulations in this area. Illegal sand and gravel
and from Guajome Regional Park extending up- mining has also removed riparian forest.
stream to 1-15, and in scattered areas above 1-15. These developments then created a need for a
Monitoring studies have found the third largest major public works project to control the flooding
vireo population in San Diego County on the San of the river over its own floodplain. The City of
Luis Rey River. Oceanside and the Corps of Engineers began con-
Current Problems struction of a large flood-control project on the
lower seven miles of the river in 1988. The river will
The area surrounding the lower San Luis Rey be confined for most of this length in a 400-foot-
River is rapidly urbanizing, and many developers wide earthen channel bounded by two levees. This
and landowners see the floodplain as a prime de- channel would significantly shrink the width of the
velopment area. In a classic situation of misplaced existing floodplain in most areas and allow for ad-
development, industrial and residential projects ditional development as well as reducing the flood
were constructed in the lower floodplain and be- risk to existing buildings.
came subject to flooding. The owners took it upon The flood-control project would remove a total of
themselves to build levees, often without permits. 146 acres of riparian habitat, of which 14.5 acres is
These actions have created a large number of illegal inhabited by Least Bell's vireos, and 46.5 acres is
suitable for vireo nesting. Another 85.5 acres of
U lower-quality riparian habitat would also be lost.
Due to the presence of the endangered vireo, the
Z City and the Corps must mitigate the loss of ripar-
ian wetland and re-create the vireo habitat and
assure it is maintained. However, there are no as-
s the vireo will use the new riparian forest.
surance
The San Diego Association of Governments re-
cently completed a habitat conservation plan for the
vireo in the San Luis Rey River watershed. This
plan sets forth measures meant to avoid the extinc-
tion of the vireo in this drainage.

Public Access
There is currently very little public land (and no
access trails) along the river. The flood control pro-
Ject includes a bike path atop the southern levee
that will be constructed by 1992. A parking lot at
Endangered Least Bell's Vireo the river mouth provides an overlook of the lagoon.

Buena Vista Lagoon

1;! M

Location and Size fills were constructed through the lagoon in 1881
for the railroad, in 1912 for the original Pacific Coast
Lagoon-Cities of Oceanside and Carlsbad, 220 Highway (now Hill Street), and in 1965 for Inter-
acres. Watershed-Cities of Oceanside, Carlsbad, state 5. These roads separated the lagoon into four
and Vista, 20 square miles. Buena Vista Creek is basins.
the main tributary stream. In 1940 a weir was placed at the mouth and the
beach berm was covered with housing, changing
History the basic function of the lagoon. The weir im-
pounded fresh water, greatly increased water
Buena Vista is one of the smallest of San Diego's depths, and excluded all tidal influence. The lagoon
coastal lagoons. Originally a tidal system, this la- was transformed into a calm-water lake. Then, in
goon used to have a small tidal prism and probably the 1970s, a 100-acre marsh at the eastern end of the
closed off most summers. Artesian springs in lagoon was filled for a shopping center. Both the in-
Buena Vista Creek, the main tributary, would have stallation of the weir and the loss of this eastern
provided fresh water in summer and given the marsh have played a major role in creating the
lagoon a brackish character with shallow water, problems that the lagoon faces today. Treated
mudflats, and marsh. Duck club ponds once sewage was discharged directly into the lagoon
marked several acres in the eastern lagoon. Road until 1967.

Land Ownership Current Problems
Most of Buena Vista Lagoon is a State Ecological Buena Vista Lagoon suffers from extreme sedi-
Reserve managed by the Department of Fish and mentation due to the effects of urbanization in the
Game. Land preservation began here in the 1950s watershed. Increased peak storm flows have caused
through the efforts of local citizens groups. A few erosion of Buena Vista Creek. After the lagoon's
small parcels on the lagoon boundaries and the far eastern marsh, which once filtered and collected
western basin are privately owned. incoming sediment, was filled in the 1960s and the
Wildlife Values lagoon was changed to a freshwater lake dissected
Buena Vista Lagoon provides one of the only by road fills, the eastern basin became a sediment
catchment basin. In 1978-79, a series of large storms
freshwater habitats on the Southern California sent tons of sediment into the lagoon. The State
coast. Numerous migratory waterfowl and some spent $1 million to remove a portion of this sedi-
shorebirds visit each year. There are also a lot of ment and to create four islands.
fish in the lagoon; catching a 3-pound bass is not In 1983, the Conservancy began working with lo-
uncommon. Small fish attract diving birds includ- cal cities in the watershed to lower peak flows and
ing brown pelicans, least terns, and Caspian terns thus reduce both erosion in the creek and sedimen-
as well as herons, egrets, and cormorants. Least tation of the lagoon. Preservation and restoration of
terns use the area for foraging following the a natural, riparian creek channel is a primary goal.
fledging of their young and have attempted to nest The Conservancy has spent nearly $1 million to fur-
on the islands in the eastern basin. ther this goal and enhance the lagoon.

Public Access
Nature study and fishing (with a license) are
allowed from shoreline access points. The lagoon
shoreline may be reached from Hill Street, Jefferson
Street, and a cul-de-sac off Marron Road near
Highway 78. The Buena Vista Audubon Society op-
erates a nature center at 2202 Hill St. in Oceanside.
It is open Tuesday through Saturday from 10 a.m.
to 2 p.m. On the second Saturday of each month,
the center offers a wildlife demonstration. More
information and arrangements for special group
presentations may be obtained by calling
(619) 439-BIRD.
The Buena Vista Lagoon Foundation is a non-
profit membership organization whose purpose is
restoring and conserving this lagoon. Contact: P.O.
Northern Pintail Box 157, Carlsbad, CA 92008.

Agua Hedionda Lagoon

Location and Size
Lagoon-City of Carlsbad, 400 acres. Watershed
-Cities of Carlsbad, Vista, and Oceanside, and
San Diego County, 29 square miles. Agua He-
dionda Creek is the main tributary stream.
History
When Spanish explorers reached Agua He-
dionda in the 1700s, it was a tidal estuary, and it
held a great deal more salt marsh than it does to-
day. The earliest map of the lagoon dates from 1887
and depicts marsh covering the western half of the
lagoon. Maps from the 1920s show a large delta
covering the eastern end, where Agua Hedionda
Creek empties into the lagoon. Road fills now sepa-
rate the lagoon into three distinct basins.
In 1954 the lagoon was completely dredged to
provide a deep basin and a source of cooling water
for the Encinas power plant. Over 4 million cubic
yards of material were removed from the lagoon. A
portion of the power plant was built on filled wet-
U
U land. jetties were placed along the mouth of the
U
lagoon to assure that the mouth does not close. A
U separate channel allows for warm water outflows.
A small residential marina development was built
on fill in the eastern basin.

U
0 Land Ownership
San Diego Gas and Electric owns most of the la-
Z goon. In the eastern end of the lagoon an area of
about 200 acres is privately owned. This land will
be transferred to the Department of Fish and Game
The wetlands of Agua Hedionda Lagoon were dredged in 1954 as a condition of the Kelly Ranch development and
to provide a source of cooling water for the adjacent power plant. dedicated as an Ecological Reserve in 1989.

Wildlife Values 1928 - 8EFORE DREDGING DONE IN 1954
LEGEND
The primary wildlife habitat is open water. MARSHAND
..... . MUDFLA TS
Various marine fish species inhabit the lagoon.
... .......
Eelgrass beds provide protection to juvenile fish
and crabs. Diving ducks as well as gulls, grebes,
pelicans, and other fish-eating birds use the la-
goon. An aquaculture operation in the western %
i4
basin raises mussels and oysters. The only marsh-
14
land lies in the eastern basin and as a thin band t
N
.............
along small areas of the shoreline. The Belding's Sa . ....... .
vannah Sparrow inhabits this marsh. Mudflats are
.............
.............
exposed in this area during low tide and are feed-
ing areas for migrant shorebirds. Least terns have
nested in salt pannes in the eastern lagoon.
Agua Hedionda and Macario creeks contain well- 1975 - AFTER DREDGING AND OTHER SHORELINE ALTERATIONS
developed riparian forests with habitat for many LEGEND
MARSHAND
FLATS
species of small songbirds. muD
Current Problems
The watershed of Agua Hedionda Lagoon is
largely in agricultural use or undergoing develOP7
ment. Agricultural operations often use erosion- . ....... V .;t....
causing techniques such as non-contour and wet-
t ... ....
.................
weather plowing. Land, graded for development . ..... 5
C,

during the winter, can cause large sediment inflows
to the lagoon. Since the 1954 dredging, the delta of
Agua Hedionda Creek has extended 50 feet into
the open waters of the lagoon. A recent mitigation
project in the eastern basin has largely been
unsuccessful. The dredging was not done to ade- Public Access
quate depths to create the expected tidal habitats
and least tern areas. The restoration of riparian for- The eastern basin is leased by the City of Carls-
est was not completed properly either. bad and operated as a water recreation area for
The outer lagoon fills with sand brought by the boats. There is fishing from the western shoreline
inflowing tide. San Diego Gas and Electric dredges of the western basin. For further information, con-
this sand from the western basin to avoid clogging tact the Parks and Recreation Department of the
the power plant intake pipes. The sandy spoils are City of Carlsbad. Access to the Ecological Reserve
placed on the beach. Neither the middle nor the in the eastern basin will be available from Park
eastern basins have been dredged since 1954. Drive off of Tamarack Avenue sometime in 1990.

Batiquitos Lagoon

Location and Size opened to the tide and often was dry for much of
Lagoon-City of Carlsbad, 600 acres. Watershed the year. San Marcos Creek was dammed in 1952,
-Cities of Carlsbad, Encinitas, and San Marcos, reducing freshwater flows to the lagoon. Between
and San Diego County, 53 square miles. San 1967 and 1974, treated wastewater was discharged
Marcos and Encinitas creeks are the main into the lagoon.
tributaries. In 1989, Batiquitos Lagoon had not been open to
tidal inflows in many years and seasonally ponds
water up to 12 feet deep.
History Land Ownership
Studies of Indian middens along the shores of Most of Batiquitos Lagoon is owned by the State
Batiquitos Lagoon indicate that the previous inhabi- Lands Commission and the Department of Fish and
tants harvested a variety of marine shellfish here. Game. The Fish and Game lands are managed as
These shellfish require continuous tidal flows to an Ecological Reserve. A few parcels along the
survive and grow. From this evidence, we may edges of the lagoon remain privately owned.
assume that Batiquitos Lagoon was a fully tidal
system until the 1800s. The earliest maps date from Wildlife Values
1898 and show marsh extending east and south of
present-day El Camino Real. The railroad, built in The lagoon is a valuable habitat for migratory
1881 across the lagoon mouth, separated the lagoon shorebirds and dabbling ducks. However, its value
from the ocean and constrained tidal flows. In 1912 to these species is directly related to its water levels
the Pacific Coast Highway further separated the and thus to rainfall. Shallow water levels in early
lagoon from tidal flows and created another fill fall are particularly important to provide feeding
across the lagoon mouth. As a result of these habitat for short-legged shorebirds and ducks. If
changes as well as sedimentation and loss of tidal water levels are several feet deep, these same
prism from watershed erosion, the lagoon was only species must seek food elsewhere. Diving ducks,
open to tidal flows intermittently by 1930. herons, egrets, terns, pelicans, gulls, and other
From 1901 to 1910, the California Salt Company species feed in the lagoon.
operated 25 acres of salt evaporator ponds in the far The endangered least tern nests at several sites
eastern area of the lagoon. A few of the dikes from in the lagoon during the summer. If water levels are
these ponds remain. A 1934 map of the lagoon still covering these sites during nesting season, the
shows duck ponds in the same area. Sediment and terns are forced to use other areas. The Belding's
thick marsh now cover the formerly open water Savannah Sparrow resides in the pickleweed marsh
ponds. Beginning in the 1940s, the lagoon rarely that rings the lagoon.

Current Problems

Air--
Water levels in the lagoon vary widely year to
year, creating a habitat of undependable value to
migratory birds. In its current state, the lagoon also
accumulates all sediment which flows in, particu-
lary fine sediment which is not collected by the
sediment basins that have been installed on several
lagoon tributaries. Topographic surveys over a
three-year period showed substantial filling of the
eastern lagoon. This problem can be expected,
given the large amount of development occurring
in the watershed. If sedimentation rates remain at
their historic levels, the entire lagoon could be filled
4@
in within 50 years.
The Port of Los Angeles evaluated the lagoon for 0
a large mitigation project beginning in 1986. The A L"
Port must compensate for filling its open-water
areas by re-creating marine habitat elsewhere. Al- Public Access
though Batiquitos Lagoon lies 100 miles south of
the Port, it has been chosen as the primary mitiga- There are two trails along the north shore of
tion site. The controversy regarding this proposal Batiquitos Lagoon. Sections of the trail are under-
centers on the proposed change of the brackish going improvement in conjunction with two upland
habitat to intertidal and marine habitats and on the developments. The trail for the east basin shoreline
amount of intertidal habitat needed to support the may be reached from Batiquitos Drive on the west
shorebird and duck species that now use the la- end or El Camino Real or Arenal Road on the east
goon. The Port would dredge the lagoon to create a end. The trail along the western basin may be
tidal prism and stabilize the lagoon mouth with reached from Windrose Circle off Ponto Drive. Na-
riprap. Most existing marsh would remain. The ture study and fishing are allowed only from
dredging and other construction activities will cost shoreline trails.
over $20 million. The Batiquitos Lagoon Foundation is a member-
The Coastal Conservancy played a key role in ship organization dedicated to protecting and
preparing the 1987 enhancement plan for Batiquitos enhancing the lagoon by providing information
Lagoon and an erosion control plan for the lagoon about the lagoon to the public and reviewing en-
watershed. In 1988 the Port of Los Angeles, City of hancement plans for the lagoon and development
Carlsbad, and Corps of Engineers began the envi- proposals in the watershed. They are a cosponsor
ronmental review and permitting process for the of this booklet. Contact: RO. Box 3103, Carlsbad,
project. CA 92009.

San UP Lagoon

Location and Size

Lagoon-City of Encinitas, 530 acres. Watershed
-cities of Encinitas, Solana Beach, and Escondido,
and San Diego County, 77 square miles. Escondido
and La Orilla creeks are the main tributaries.

History
San Elijo Lagoon was once a fully tidal system,
as evidenced by archaeological studies. Field notes
that accompany the first map of the lagoon, dating Land Ownership
from 1887, state: "it is for a mile inland a shallow la- The Department of Fish and Game owns the
goon in winter and in the dry season a glistening middle basin and a portion of the western basin.
akaline plain." This description indicates that year-
round tidal inflows may have stopped by this time; San Diego County owns much of the eastern basin.
however, the map does show an open lagoon Both the middle and eastern area are managed as
mouth. At the time of the description, two man- an Ecological Reserve. The western basin is owned
made obstructions crossed the lagoon-the rail- partially by the San Elijo Lagoon Foundation and
road, set mostly on fill with a small bridge, and partially by private owners.
a 1000-foot-long levee across the middle of the
lagoon. Wildlife Values
Between the 1880s and 1940s numerous dikes
and levees were built in San Elijo Lagoon. Some San Elijo Lagoon is primarily a shallow-water
were for duck ponds and roads, and later ones were brackish wetland that rarely experiences tidal flows.
for sewage treatment ponds. The large fills for high- Following winter storms, water levels increase and
ways and railroads no doubt reduced stormwater the lagoon mouth opens, draining the stormwater
velocities and increased the rate of sediment depo- and allowing tidal inflows for a short period. Most
sition. Several large reservoirs on Escondido Creek of the year the lagoon mouth is closed. Migratory
also reduced freshwater inflows. Highway I created shorebirds and waterfowl visit San Elijo Lagoon in
a large dike along the lagoon's western boundary large numbers. The shallow water areas are produc-
and severely restricts the entrance channel and tive feeding grounds rich in invertebrates and
tidal inflows. From 1940 until as late as 1973, San aquatic insects. Small fish also flourish in the la-
Elijo Lagoon received wastewater from the City of goon when water quality is good. Seven species of
Escondido. These changes have transformed the terns feed on these small fish as do herons, egrets,
lagoon from its 1887 description. and other water birds.
50

The former users of the lagoon have left many Santa Carina Drive on the south side of the lagoon,
levees and diked-off ponds. These areas are some- along El Camino Real near the corner of Rancho
what isolated from the rest of the lagoon and Serena at the east end of the lagoon, and off Man-
harbor freshwater marsh or, in several cases, salt chester near San Elijo Drive on the north side of
marsh. This patchwork of marsh types makes for a the lagoon. Contact the Parks and Recreation De-
high diversity of habitats and a large number and partment of San Diego County at (619) 694-3030 for
variety of wildlife species. more information.
Nine endangered species visit or reside in San Three organizations are concerned with this
Elijo Lagoon. Least terns feed here and nest on the lagoon. The San Elijo Lagoon Volunteers patrol the
islands created for them in the eastern basin. Clap- lagoon for illegal hunting, fishing, dumping, and
per rails inhabit the eastern lagoon and also live in other activities. Contact San Diego Parks and Rec-
the dense freshwater marsh. Not far from the rails, reation for more information.
Belding's Savannah Sparrow nests in pickleweed The recently formed San Elijo Lagoon
marsh. Brown pelicans use the open water areas of Conservancy monitors and assists in maintenance,
the lagoon to rest and feed. planning, and management of the reserve. Contact:
2365 Newcastle Ave., Cardiff, CA 92007.
Current Problems The San Elijo Lagoon Foundation monitors
Sedimentation problems are not well studied at maintenance and management of the lagoon and
San Elijo Lagoon. Much of the Escondido Creek owns some land in the western basin. Contact:
floodplain directly above the lagoon remains P.O. Box 1001, Solano Beach, CA 92075.
natural, covered with marsh and riparian forest.
Sediment is stored within this area and little may mow
be reaching the lagoon. Efforts to channelize the
creek could easily change this situation since this
floodplain remains privately owned and subject to
development proposals. Erosion of the bluffs sur-
rounding the lagoon by urban stormwater, and
sedimentation of wetlands, are quite apparent,
particularly along the southeastern lagoon edge. '7
Beginning in 1989, the County Parks Department
plans to open the lagoon mouth more frequently
and increase tidal flows to the lagoon. The railroad
and Highway I bridges constrain the lagoon ............ K,
mouth, making it difficult to maintain an open
channel for very long.

Public Access
The public is allowed to hike or fish from desig
nated trails around the lagoon. These trails may be SIM-
U
reached from the end of Rios Avenue, the end of

San Dieguito Lagoon

Location and Size World War 11. The construction of Interstate 5 in
Lagoon-Cities of Del Mar and San Diego, 300 1966 through the middle of the lagoon isolated the
acres. Watershed-City of San Diego, County of wetlands on the eastern edge of the lagoon. An-
San Diego, 350 square miles. The San Dieguito other fill for a shopping center in the 1970s further
River is the main tributary. reduced the wetland acreage.
From 1940 to 1974, 200,000 to 300,000 gallons of
History sewage effluent were discharged daily into treat-
ment ponds in the western area of the lagoon.
San Dieguito Lagoon was the largest of the six The liquid portion of this sewage was released into
San Diego coastal lagoons and has the largest wa- the lagoon channels and created a thick layer of
tershed. Near the mouth of San Dieguito Lagoon sludge on the lagoon bottom. Two large dams were
are Native American midden sites that contain constructed on the San Dieguito River, greatly
some of the oldest dated shell material in Cali- reducing freshwater inflows. The result of all these
fornia. These shells are over 50,000 years old, activities was year-round closure of the lagoon
suggesting that ancient man inhabited the shores mouth beginning in the 1940s. Only large winter
of this lagoon. floods forced the mouth open.
The earliest maps of this lagoon date from 1887 The Conservancy began an enhancement project
and depict several miles of tidal channels, marsh, for San Dieguito Lagoon in 1978. The original en-
and mudflat extending from the lagoon mouth well hancement plan produced by the City of Del Mar
inland past the present location of Interstate 5. Al- was implemented in part with a $1.3 million grant
though the railroad had been built by this time, the from the Conservancy in 1983. A tidal basin was
lagoon mouth clearly had an open channel. The dredged in a 70-acre area of the southern lagoon,
marsh area alone is believed to have been over 600 and an enormous gully in Crest Canyon was re-
acres, while the entire lagoon probably covered stored with the dredge spoils. The lagoon mouth
1,000 acres. was opened, returning tidal flows in the river chan-
San Dieguito has undergone major filling activ- nel all the way to El Camino Real.
ities and lost over half of its marshes. The railroad,
Highway 1, and Jimmy Durante Boulevard were
built on fill in the lagoon. Early land development
(1905) by the South Coast Land Company filled the
sout
hern lagoon between Highway 1 and the rail
road. The Del Mar Fairgrounds were built on a 200-
acre section of the northern lagoon in 1935. The
wetlands east and west of Jimmy Durante Boule-
vard were progressively filled or developed. Del
Mar airport was built on lagoon wetlands during Striped Mullet
52

Land Ownership shallow-water fish habitat that is used by mullet,
The Department of Fish and Game owns and mudsucker, and topsmelt, among others. A wide
manages 107 acres of the restored area of the la- array of invertebrate species has recolonized the
goon as an Ecological Reserve. The City of San restored area and the river channel as well.
Diego owns a 20-acre abandoned sewage treatment Current Problems
pond now overgrown with riparian trees as well as
another 29 acres of wetlands. The 22nd District Ag- San Dieguito Lagoon is the only lagoon in
ricultural Association owns 23 acres of wetlands which most of the land is not publicly owned. The
and beach in the western lagoon in addition to the privately owned lagoon and river channel are con-
fairgrounds. The remainder of the western lagoon stantly being threatened with development.
as well as the river channel and remnant wetlands On the western side of 1-5 there are several de-
east of 1-5 are privately owned. velopment proposals. The Fairgrounds is seeking to
build an additional off-ramp from northbound 1-5.
Wildlife Values Another private landowner of the western lagoon
Tidal salt marsh has survived along the river attempted to develop a hotel on the old airport site
channel and in the tidal basin, and non-tidal pick- and met with vigorous local opposition. A small
leweed marsh exists in several areas of the eastern housing development is proposed for an area near
lagoon and near the old airport site. Tidal mudflats the lagoon shoreline and Crest Canyon. Another
cover the river channel and tidal basin margins. adjacent development caused sedimentation into the
There is also riparian habitat in the lagoon as well restored tidal basin, and the developer must re-
as considerable filled area that could be restored to dredge the damaged area. In 1988 the Port of Los
tidal marsh. Angeles and the Port of Long Beach began a fea-
Since the restoration of tidal flows and dredging sibility study of using this lagoon as a mitigation
of a new tidal basin, water birds are more common site for their proposed landfills.
at San Dieguito Lagoon. Shorebird use in particular
has increased as intertidal feeding areas were re- Public Access
stored. Osprey recently began using the western The only area of the lagoon open to public access
lagoon. The flooded grassland in the eastern river is the Department of Fish and Game Ecological Re-
valley is visited by Canada geese in the winter. serve. Nature study and fishing are allowed from
Two endangered species use San Dieguito the shoreline and the Grand Avenue bridge. Crest
Lagoon. The least tern forages for fish in the tidal Canyon, a local park, has hiking trails with views
basin, but has not been successful at nesting in the ofthelagoon.
western basin recently. The terns used to nest just Two nonprofit organizations are associated with
east of 1-5 on the salt panne areas now surrounded this lagoon. The San Dieguito River Valley Land
by tomato fields. The Belding's Savannah Sparrow Conservancy was formed to conserve, restore, and
inhabits the pickleweed marsh of the lagoon. Fish enhance the river valley. Contact: 201 Oceanview,
and Game is currently planting cordgrass on a trial Del Mar, CA 92014. The Friends of the San Dieguito
basis to create new habitat and reintroduce the River Valley are concerned with the conservation of
clapper rail to the lagoon. open space through lobbying and education efforts.
The restoration project created additional Contact: P.O. Box 973, Del Mar, CA 92014.

Los Pen'asquitos Lagoon

Location and Size Sewage effluent was discharged into the lagoon
Lagoon-City of San Diego, 630 acres. from 1962 to 1972 in quantities ranging from 500,000
Watershed-Cities of San Diego and Poway, and to I million gallons per day. Accidental spills of mil-
San Diego County, 98 square miles. Los Pefias- lions of gallons of raw sewage have been a
quitos and Carmel Valley creeks are the main continual problem in the lagoon since 1984. The
tributaries. City of San Diego has now completed some repairs
of their sewer pumps, which should help to avoid
these spills.
History Land Ownership
When the Spanish explored the coast and named
Los Pehasquitos Lagoon in 1769, they encountered The State Department of Parks and Recreation
a comparatively deep-water estuary that supported owns most of the lagoon and manages it as part of
numerous kinds of marine animals. The 1889 map Torrey Pines State Reserve. The Conservancy owns
of Los Pefiasquitos Lagoon, also labeled Soledad 20 acres of the upper lagoon near the outlet of Los
Valley, shows an open mouth located at the north- Pehasquitos Creek. The City of, San Diego owns
ern edge of the beach berm. Marsh extended up much of Los Pefiasquitos Creek Canyon and man-
Carmel Valley and far up Sorrento Valley. At this ages it as a preserve.
time the railroad crossed the eastern edge of the Wildlife Values
lagoon and followed west along the present course
of Carmel Valley Road. In 1925 a new railroad Pickleweed marsh dominates the western por-
embankment was built through the center of the la- tion of the lagoon, while riparian vegetation covers
goon, creating a major impediment to tidal flows. the eastern lagoon and outlets of Los Pefiasquitos
Twelve years after the railroad construction, High- and Carmel Valley creeks. A series of tidal channels
way I was built across the mouth of the lagoon. As near the lagoon mouth provide open water habitat
with the other lagoons, this highway constricted and mudflat areas for invertebrates. Salt panne that
the lagoon mouth, and the lagoon began closing. seasonally floods occurs in the upper lagoon and
Analysis of sediment cores in the lagoon showed probably supports aquatic insects. Bird use of the
a substantial increase in the sedimentation rate since lagoon differs between the salt marsh and riparian
the plowing and grading of the lagoon watershed. habitats. Waterfowl and other water birds such as
Before European settlement, the lagoon had been herons and egrets use the western and central por-
slowly filling in at a rate of 10cm (4 inches) per cen- tions of the lagoon. Shorebird use is relatively low
tury. The sedimentation rate in 1980 had increased because there is little intertidal or unvegetated
to 50cm (20 inches) per century and may be consid- shallow water habitat. The riparian habitat hosts
erably higher now due to the grading and develop- numerous species of songbirds as does the adjacent
ment in the watershed over the last nine years. sage scrub habitat.

Belding's Savannah sparrows inhabit the pick-
leweed marsh and are particularly abundant in an
area of salt grass near the mouth. Clapper rail were
more numerous in the lagoon when cordgrass was
present before the 1940s. Only two clapper rails
have been heard in the past year. Least terns; also
once nested in the salt pannes in the lagoon. Now Z
the terns only feed in the lagoon area.
Current Problems

Los Pehasquitos Lagoon suffers from two major
and interrelated problems: sedimentation and lack
of tidal flow. Thousands of acres in the lagoon wa-
tershed have been graded and paved in the last
eight years. The effect of these massive earth-mov- 0
ing operations is now becoming apparent in the
lagoon. The tidal channels have filled in signifi-
cantly; salt marsh is being smothered and changed
to riparian forest or upland. Despite a number of
controls on grading in the coastal zone portion or
the watershed, the lagoon is filling in. Large sums lagoon. Developments a bit further east outside the
of public money will be required to restore this coastal zone pay no fees, but may cause problems
lagoon. in the lagoon. It is not clear that these fees will be
Due to both sedimentation and the Highway I adequate to complete restoration projects in the
bridge, the lagoon rarely stays open, even after a lagoon.
bulldozer opens the mouth. The Conservancy and
the Los Pehasquitos Lagoon Foundation prepared Public Access
an enhancement plan for the lagoon in 1985. As
part of this program the Foundation has been There are currently no trails that cross through
opening the mouth during periods of low tide, low the lagoon or mark its edges. There is a parking lot
surf, and lagoon high-water levels. The lagoon has near the mouth that has access to the beach, and
consistently closed off after these openings, staying both Carmel Valley and Sorrento Valley roads bor-
open a maximum of three weeks. der the lagoon. The bluffs of Torrey Pines State
The Foundation receives funding for these Reserve above the lagoon offer a panoramic view of
enhancement activities from developments in the this wetland.
coastal zone area of the watershed. The develop- The Los Pehasquitos Lagoon Foundation is a
ments pay a small fee for each house or commercial membership organization active in enhancing and
area to compensate for the erosion and sedimen- preserving the lagoon. Contact: P.O. Box 866, Car-
tation problems the developments cause in the diff, CA 92007.

Mission Bay, Famosa Slough,
and the San Diego River

Location and Size Engineers began dredging the bay and rerouting
Mission Bay-City of San Diego, 4,600 acres. the river once again. Dredge spoils were used to
Watershed-City of San Diego, County of San build lands within the bay and to construct levees
Diego, 53 square miles. Tecolote and Rose creeks for a new river channel. The final project created
'ity Mission Bay Park, a complex of recreational islands,
are the main tributaries. Famosa Wetlands-C
of San Diego, 31 acres. San Diego River-tidal beaches, and waterways, and the San Diego River
wetland-City of San Diego, 300 acres. Watershed flood control channel. The channel carries the river
-Cities of San Diego and Santee, and County flows directly out to sea. Only two remnants of nat-
of San Diego, 440 square miles. ural marsh remain-Kendall Frost Marsh Preserve
and Famosa Slough.
History Land Ownership
The Spanish originally called this large estuary The City of San Diego owns most of Mission
False Bay because its entrance was near enough to Bay, the lower flood control channel from 1-5 to the
San Diego Bay to occasionally fool ship captains. ocean, and Famosa Channel. The University of Cal-
False Bay spread over 5,000 acres and was once a ifornia Natural Land and Water Reserve System
deep-water embayment. At the time of the Spanish owns the Kendall Frost Marsh Preserve. Famosa
settlement the San Diego River drained into north- Slough is privately owned.
ern San Diego Bay. Marshes and mudflats extended
from the southeastern shore of False Bay to the Wildlife Values
northeastern shore of San Diego Bay. High tides Mission Bay contains three types of aquatic habi-
isolated Point Loma from surrounding lands. tats-sandy bottom shallow water, eelgrass beds,
Shortly after California achieved statehood in and rocky shoreline-and two types of intertidal
1850, the Army Corps of Engineers, in one of their habitats-mudflat and marsh. The aquatic habitat
first river projects, rerouted the San Diego River to supports over 25 species of marine fish and nu-
drain into False Bay. The old river delta could now merous invertebrates. Eelgrass is particularly
be filled and developed and the port facilities in widespread in Mission Bay due to the shallow
San Diego Bay would no longer silt in. Instead all depths.
the sediment from this large watershed began to Most birds using the bay are species preferring
deposit in False Bay. By the turn of the century, open water habitats-diving ducks, pelicans, cor-
False Bay was very shallow, and local residents morants, grebes, and loons. The small area of
claim they could walk across it at low tide. mudflat limits shorebird use. The small marsh at
During the 1940s the City of San Diego began Kendall Frost supports both clapper rail and savan-
looking at False Bay as a potential small-craft nah sparrows. Least terns nest on several islands in
harbor and recreation area. The Army Corps of the bay.
56

The Famosa wetlands and the lower San Diego SAN DIEGO HISTORICAL SOCIETY-TICOR COLLECTION
River channel are important migratory bird habi-
tats. The river channel is a fully tidal system with
mudflats, salt marsh, and, east of 1-5, riparian for-
est. Famosa Slough, despite its small size and
urban surroundings, hosts a wide variety of bird
species and contains freshwater, brackish, and salt
marsh habitats. Least terns forage in both the
Famosa wetlands and the river channel.
The upper San Diego River floodplain contains
over 800 acres of riparian forest and supported over
30 pairs of vireos in 1988. The majority of these W
vireos nest in Mission Gorge and Mission Trails
Regional Park.
Current Problems
Water quality problems at Mission Bay affect Dredging of Mission Bay in 1956.
both its value as an aquatic habitat and as a water
recreation area. The two tributary streams, Tecolote the plan would conserve the existing riparian forest
and Rose creeks, carry both urban pollutants such through redesign of projects and attempt to in-
as dead plant materials, oil, grease, and fertilizers, crease the habitat in some areas through revegeta-
and high sediment loads into the back bay. In addi- tion activities.
tion, sewer lines back up occasionally into the back Famosa Slough has been a subject of controversy
bay. The lack of water circulation in the back bay al- for over a decade. The owner of the slough has con-
lows these pollutants to accumulate, and the area sistently sought to develop his land while local
has been quarantined for several months at a time. citizens groups have fought for public ownership.
In 1989 the City of San Diego completed several As of 1989 the City of San Diego was negotiating
projects that should reduce water quality problems. with the owner to purchase the slough.
A $1.4 million creek stabilization project should re- Public Access
duce erosion from Urban stormwater in Tecolote
Creek. The City is also repairing and replacing Mission Bay has numerous public facilities.
many of the sewer lines and inspecting local restau- Contact the City's Visitor Information Center at
rants to reduce grease inflows, the main cause of (619) 276-8200. Hiking and bicycling paths top the
sewer problems. levees of the San Diego River flood control channel.
Numerous residential, industrial, and trans- Famosa Slough can be viewed from West Point
portation developments threaten to remove the Loma Boulevard.
riparian forest of the San Diego River floodplain. The Friends of Famosa Slough are a nonprofit
The San Diego Association of Governments re- organization concerned with public ownership of
cently completed a habitat conservation plan for the slough and protection of lower river channel.
riparian habitat on the floodplain. If implemented Contact: 2776 Nipoma St., San Diego, CA 92106.
57

San Diego Bay

U
J it '-J 0
U

ll live
T 0
U
Air

Iim

Filling wetlands in 1915 to build the Embarcadero at the foot of Broadway, downtown San Diego.
Location and Size
Bay-Cities of San Diego, Coronado, National whales used the bay as a calving ground. Native
City, Chula Vista, and Imperial Beach; subtidal and Americans lived along the shoreline, harvesting
intertidal areas-11,130 acres, salt ponds-1,400 fish and shellfish from the productive shallow
acres. Watershed-Citie� of San Diego, Coronado, waters.
National City, Chula Vista, Imperial Beach, La The earliest maps of the bay show a nearly solid
Mesa, Lemon Grove, and El Cajon, and County of border of mudflats around the shoreline. Marshes
San Diego, 415 square miles. The Sweetwater and filled the mouths of the Sweetwater, Otay, and San
Otay rivers and Chollas and Paradise creeks are the Diego rivers as well as Paradise and Chollas creeks.
main tributary streams. The bay was relatively shallow, contained large wet-
land areas, and received a great deal of fresh water.
History Americans first came to San Diego Bay to trade
In 1769 the Spanish chose San Diego Bay as the with the Spanish and to hunt the whales and later
site of their first northern colony to make use of to settle in the area. By 1830, sixteen American
this fine natural harbor. These first explorers saw a whaling ships were operating in the bay. This in-
very different landscape than exists today. Gray dustry peaked in 1871 with the near extinction of

the gray whale. Seven years after California be- lands) of San Diego Bay under a grant from the
came a state in 1850, the Army Corps of Engineers California Legislature. The State Lands Commis-
diverted the San Diego River away from the bay sion retains ownership of 42 percent of the bay,
into False (Mission) Bay because the river kept mostly underwater areas. The military controls al-
silting in San Diego harbor and interfering with most 20 percent, and city and county governments
shipping. The large marshy river delta was then have jurisdiction over less than 1 percent of the bay.
filled and developed into the City of San Diego. Over half of the salt ponds in the south bay are pri-
Major maritime development of the bay extended vately owned, and the remainder is owned by the
from the late 1800s to well past World War II. Dur- State Lands Commission and operated under a
ing this period 100 million to 140 million cubic yards lease. As a result of a lawsuit in 1988, the Fish and
of bay sediment were dredged and used to fill Wildlife Service received ownership of the entire
tidelands and widen the beaches along the Silver Sweetwater and Paradise Marsh complex, a 315-acre
Strand. Piers and port facilities were created for refuge.
both domestic and military uses. In 1962, the San
Diego Unified Port District was created, consolidat- Wildlife Values
ing the port facilities of five shoreline cities. Naval Several types of habitat in San Diego Bay are im-
facilities in the bay are home base to nearly 20 per- portant to wildlife-open water, mudflat, marsh,
cent of the Navy's active fleet. Other military uses and salt evaporation ponds.
include an amphibious and underwater demolition Open water covers 10,165 acres of the bay below
training base and a Marine Corps recruit base. the low-tide line. Deep and shallow subtidal habi-
The development of San Diego Bay into a major tats and eelgrass beds predominate. The north and
military and domestic port has been accomplished central bay areas have been dredged for ship chan-
through the destruction of most of its wetlands. nels and port facilities and have depths varying
The bay is now much deeper and narrower than it from 18 to 70 feet. Shallow subtidal habitat ranges
was 150 years ago, and most shoreline development from the low-tide line to 18 feet deep and is concen-
sits on fill. Only the south bay contains significant trated in the southern bay and a few other shore-
areas of marsh, mudflat, and salt ponds. Overall, line locations. Eelgrass beds cover about 800 acres
27 percent of the bay's tidal area has been filled. throughout the bay.
In 1888 a dam was built on the Sweetwater River Many types of fish and invertebrates inhabit
to provide drinking and irrigation water. The Otay the deep and shallow subtidal areas. Surveys have
River also was dammed, in 1919. As a result, fresh- found 80 to 90 fish species in the bay. Generally, the
water inflows have been reduced to 75 percent of deeper north bay supports open-ocean fish, while
their historic levels, and the bay is now primarily a the warmer, shallower south bay supports smaller
saline system. estuarine fish.
Eelgrass beds are a productive refuge for juve-
Land Ownership nile fishes and crustaceans. Studies of San Diego
The San Diego Unified Port District administers Bay found that more species of fish use eelgrass
37 percent of both the submerged and the historic than the other subtidal habitats. Certain species,
tidelands (both filled and remaining natural wet- such as topsmelt and shiner surfperch, use eelgrass

beds to spawn. Their offspring remain in the pro- Of the marshes that once bordered San Diego
ductive, protected eelgrass until they are large Bay, only 10 percent remain. This remnant consists
enough to enter the open ocean. Recreational and of 203 acres, primarily at the Sweetwater and
commercial fish as well as small forage fish live in Paradise Marsh complex. Resident birds include
the eelgrass beds. savannah sparrow and clapper rail. Least terns
Diving ducks, primarily surf scoter and scaup, nest on a large fill within the marsh complex.
congregate on the open waters of the bay during
the winter. These species have declined by 90 per- Current Problems
cent since the late 1960s. The suspected cause of Current resource problems in San Diego Bay fall
this precipitous decline is the enormous increase in into several categories-water quality issues, pro-
boat traffic in this same period. During the 1880s posed dredge-and-fill projects in wetlands, and a
great concentrations of waterfowl used the interti- proposed southern bay entrance.
dal areas of the north bay. One observer counted During the 1940s and '50s the bay was described
50,000 Black Brandt on a single day in Spanish as a "metropolitan cesspool *" Fifteen sewers dis-
Bight, an inlet which once existed on North Island. charged raw or minimally treated sewage directly
After the filling of much of the bay tidelands, into the bay. The water was a murky green-brown
brandt have seldom been seen. almost devoid of aquatic life. An ocean outfall was
The mudflats of south San Diego Bay are the constructed at Point Loma in 1963 at the insistence
largest shorebird feeding area in San Diego County of the Regional Water Quality Board. Long-term
and are a significant stopover for shorebirds of the studies of the bay's fish and invertebrates have
Pacific Flyway. Only half of the mudflat habitat that shown that those species that died from the pollu-
existed in 1850 in the bay remains, a total of 766 tion of the 1950s began to return in the 1970s.
acres. In winter months, feeding shorebirds and Current water quality problems are less obvious
other water birds crowd onto these mudflats. and center on high levels of certain toxins in bay
The salt ponds of the south bay provide addi- sediments. PCBs occur in several locations, most
tional feeding habitat for shorebirds and roosting notably in Convair Lagoon, where contaminated
and nesting areas for many species. Salt production shellfish are quarantined. Copper in the mud at the
creates water-filled hypersaline ponds, which are 24th Street Marine Terminal copper ore loading fa-
inhabited by tiny brine shrimp. Northern pha- cility exceeds safe levels and must be cleaned up.
laropes, eared grebes, and other birds feed in these Both copper and tributyltin leach from antifouling
ponds. The drawdown and drying of the salt ponds paint on boat hulls, and mud near shipyards con-
create a mudflat-like feeding ground for numerous tains large amounts of paint chips and toxins.
shorebirds. Waterfowl and many other water birds These compounds kill shellfish. Storm drains bring
rest on the water that remains calm during high oil and grease washed off sidewalks and roads into
tides and storms. The levees surrounding the the bay, causing fin rot in fish. As the bay water-
ponds, which are isolated and typically barren of shed is developed, the concentrations of these
vegetation, serve as nesting grounds for five spe- compounds could greatly increase. The Regional
cies of terns, including least terns, as well as black Water Quality Control Board has initiated the San
skimmer and snowy plover. Diego Bay Clean Up Project, which is sampling
60

toxin areas, identifying their sources, and regulat- Public Access
ing toxic discharges.
The demand for private, recreational marinas in Numerous points on the bay shoreline are acces-
San Diego Bay is very high. Several marinas that sible to the public. Contact the Port of San Diego at
would affect wetlands have been proposed. One (619) 291-3900 for information. The nonprofit
would be constructed in National City, near 32nd Bayfront Conservancy Trust operates the Chula
Street, and another in Imperial Beach, along the Vista Nature Interpretive Center. The Center is
Otay River. Both could have detrimental effects on open from 10 a.m. to 5 p.m., Tuesday through Sun-
wetlands. day, and is accessible only by shuttle bus. The bus
A second entrance to San Diego Bay has been leaves from the corner of E and Bay streets, just off
proposed for many years. It would be constructed 1-5 in Chula Vista, at 5 and 35 minutes after the
through the Silver Strand at Crown Cove. Because hour. Admission to the center is free, but the bus
of the length of the bay, boat travel from marinas in costs 50 cents for anyone over 17. The Center offers
Chula Vista or Coronado Cays to the open ocean is numerous special programs including bird walks
considered to be too long. A second entrance would the first and second Sundays of every month from
make the south bay more accessible to recreational September through April. Special group tours may
boats. The effects of such a second entrance on the be arranged by appointment. Contact: 1000 Gun-
south bay wetland habitats would be damaging, powder Point Dr., Chula Vista, CA 92010. (619) 422-
however. The shallowness of the south bay and its BIRD (-2473).
broad mudflats attract thousands of birds and sup- The Southwest Wetlands Interpretive Associa-
port many fish. Increasing tidal circulation and tion is a nonprofit organization concerned with
deepening of this area would decrease the size and preservation of the south bay. Contact P.O. Box 575,
quality of the habitat. As of 1989 this proposal was Imperial Beach, CA 92032.
being studied by a coalition of several south bay
cities and remained very controversial. Np 11
The riparian forest of the Sweetwater River sup-
ports endangered Least Bell's vireos. The largest a
congregations of this species occur around the U
southeastern Sweetwater Reservoir and upstream
=A,71@
it
to Jamacha Valley. A number of developments could R
affect this area, including sand mining, highway E_ 14
expansion, increased water storage, and housing
developments. The San Diego Association of Gov-
r
ernments released a habitat conservation plan for
the river in 1988. Numerous development proposals @J
along the riparian floodplain of the Otay River have
been made. The Conservancy and local govern-
ments began an enhancement plan for the lower Z
river floodplain in 1989.

Tijuana Estuary

ary's seaward edge has resulted in waves washing
Sand directly into the marsh. Vegetated dunes pro-
tect wetlands by capturing and holding sand blown
inland from the beach. They gradually grow taller
until large waves erode the sand away and the pro-
cess resumes. During the 1960s and '70s, apartment
A buildings were erected on most of the northern
dunes, the beach, and some filled marshland.
Dune plants cannot withstand much trampling or
off-road vehicle abuse. As the population of Impe-
rial Beach grew, the dunes became more and more
denuded. Without shrubs and grasses, the dunes
no longer captured sand and shrank in height. In
1983 waves washed over the dunes during high surf
and high tides, moving sand into the northern
marsh and the entrance channel. Four months later
Long-billed Curlew the mouth closed, and both the northern marsh
Location and Size and the mouth had to be dredged. The entrance
Estuary-Cities of San Diego and Imperial channel now measures only 100 feet wide and is
Beach, 1320 acres. Watershed-Cities of San Diego susceptible to closure.
and Imperial Beach, County of San Diego, State of
Baja California Norte, Mexico, 1730 square miles. Land Ownership
In 1982 NOAA designated Tijuana Estuary a Na-
History tional Estuarine Sanctuary (later it was renamed a
Unlike many of San Diego's wetlands, Tijuana National Estuarine Research Reserve). The Conser-
Estuary is not dissected by highways and railroads. vancy purchased a large area for the Reserve and
Development has proceeded along the estuary's turned it over to the City of San Diego. The U.S.
edge and filled some marshes. The estuary's fea- Fish and Wildlife Service, U.S. Navy, and California
tures have been affected mainly by sedimentation Department of Parks and Recreation are also major
from watershed erosion and wash over of sand landowners. Of the 2,530 acres in the Reserve, only
from denuded sand dunes. Since 1852, the estuary 800 are still privately owned.
has lost 80 percent of its tidal prism. Between 1852
and 1986 the Tijuana River flooded severely seven Wildlife Values
times and sediment filled 200 acres in the estuary. Tijuana Estuary is one of the largest and best
The southern arm lost 250 acres due to both sedi- studied wetlands in Southern California. It contains
mentation and agricultural reclamation. several habitat types; intertidal salt marsh is the
The destruction of sand dunes along the estu- most extensive.
62

In the high marsh, pickleweed supports a large
population of Belding's Savannah Sparrow, which
feed on abundant insects. The endangered Salt
Marsh Bird's Beak also grows here. The lower
marsh is dominated by cordgrass and is home to
the Light-footed Clapper Rail. In 1983 Tijuana
Estuary supported 17 percent of the statewide
population of this endangered species. After the
estuary mouth closed in 1984, much of the cord-
grass died and the rail became extinct in the
estuary. Since then several rails have been seen,
but the population has not recovered.
Salt pannes are ponds in the marsh that dry out
in the summer. In winter waterfowl feed on the
blooms of aquatic insects and vegetation. In sum-
mer the dry, salt-encrusted panne has an under-
ground world of burrowing insects. One species of z .
these insects, the tiger beetle, is proposed for fed-
eral and state listing as threatened. Least terns and k
snowy plovers also nest on these dry pannes. The City of Tijuana, Mexico
Intertidal channels and mudflats are the primary part of the city. The sewer line breaks and leaks raw
feeding area for shorebirds that migrate to the estu- sewage into the southern portion of the estuary. An
ary. There is some evidence that birds which feed at intercept line carries 15 million gallons of sewage a
Tijuana Estuary also feed at south San Diego Bay day to the Point Loma treatment plant for process-
and move between the two wetlands. Tidal chan- ing. But over half the city lacks a sewer system of
nels support estuarine fishes, which attract least any kind. Septic systems, pit toilets, or street gut-
terns from their large nesting colony on the beach ters serve thousands. Stormwater washes much of
and dunes. this raw sewage into the Tijuana River and down
Current Problems into the estuary. A sewage flow of 12.5 million
gallons a day was measured in 1988 in the river.
Tijuana Estuary faces three primary problems- Within the next five years a new water supply
watershed pollution and sedimentation, nearby pipeline will reach Tijuana, greatly increasing this
large-scale land grading, and disturbance from wastewater outflow.
illegal immigration. The wastewater has two effects on the estuary. It
Over two-thirds of Tijuana Estuary's watershed carries large amounts of nutrients, pollutants, and
lies in Mexico and encompasses the City of Tijuana. possibly toxins into the estuary, causing quarantine
This booming border town of 1.5 million people has and public health risks. It also reduces summer
a limited and often non-functional sewer system. salinity levels, killing many marine invertebrates
One outdated sewage treatment plant serves only a and fish.
63

The United States and Mexico are cooperatively in helicopters. This ground traffic has damaged the
evaluating many proposals for how to stop the flow marshes and created numerous compacted trails.
of sewage into the estuary. These proposals range Public Access
from building a larger pipeline to bring more sew- Views of the estuary are available from the Impe-
age to Point Loma, to building a new regional rial Beach side of the Reserve. There are nature
wastewater plant on the California side of the bor- walks on the first Saturday of every month. Meet at
der, to building a new treatment system in Mexico 9 a.m. at Fifth and Iris streets. Special walks for
with a new ocean discharge pipe. Most of the pro-
school groups are available once the group's
posals do not address the problem of extending a teacher has completed a training session. Contact
sewer system to the households in Tijuana that cur- Pat Flanagan, reserve education coordinator, at
rently lack one. For Tijuana Estuary the primary (619) 238-3189 for information.The sand dunes are
concern will be to minimize freshwater inflows closed to all public access to protect their fragile
during the dry season. plants. On the southern side of the Reserve, Border
The Tijuana River also brings sediment into the Field State Park at the end of Monument Road of-
estuary. After the 1980 flood, over two inches of fers a good overview. Call the Department of Parks
sediment had accumulated in parts of the marsh. and Recreation to see if the park is open before vis-
Sedimentation, which contributes to the loss of . iting: (619) 237-6766. The interpretive center at 301
tidal prism in the estuary, is caused by poor agri- Caspian Way in Imperial Beach is scheduled to
cultural practices in the watershed on both sides of open in 1990.
the border. The County of San Diego is investigat- The nonprofit Southwest Wetlands Interpretive
ing the possibility of buying portions of the lower Association has been concerned with preservation
river valley, restoring its riparian habitat, and so and restoration of Tijuana Estuary for the past ten
possibly reducing sediment flow into the estuary. In years. Contact: P.O. Box 575, Imperial Beach, CA
1988 the Conservancy funded an environmental re- 92032.
view of a major enhancement plan for the estuary
which would remove accumulated sediment and Diatoms
restore a large tidal prism.
A large sand and gravel excavation project is
being proposed on Spooners Mesa bordering the
southern estuary. Over 50 million cubic yards of
sand and gravel would be removed, diminishing
the height of the mesa substantially and producing
copious dust, noise, and disturbance to the estu-
ary's wildlife. As of mid-1989 the environmental
review for the project was just beginning.
Because Tijuana Estuary lies next to the
Mexican-U.S. border and is isolated, it is a nightly
highway to hundreds of illegal immigrants. Border egg and larvae of a wetland fish,
patrol officers pursue them both on the ground and topsmelt

Acknowledgements
Our special thanks to Dr. Joy Zedler, Dr. G. Mathias Kondolf and Dr. Ted Winfield for
reviewing the entire manuscript and adding their valuable comments. For contributing
information, photographs or illustrations we'd like to thank-Dr. Keith MacDonald,
Tom Firle, Pierce Harris, Greig Peters, Robert Hoffman, Stephen Neudecker, Pat
Flanagan, Mark Weitzel, Paul Jorgensen, Elizabeth Copper, Evelyn Ashton, Slater Buck,
Adam Birnbaum, Nancy Kaufman, Nancy Gilbert, Martin Kinney, Robin Stribley, Jay
Barnett, Nancy Weare, Pat McCoy, Phil Unitt, Gary Page, Scott Fulmer, Michael
McLaughlin, Jim Peugh, Paul Fromer, Glen Lucos, Dave Weaver, Bill Dysen, Gary
Sanchez, Ruth Potter, Alice Goodkind, Pam Beare, Keith Merkel, Bill Tippets, Teresa
Stewart, Susan Welker, Robert Patton, Phillip Roullard, Scott Jenkins, Michael
Armbrust, William Brown, Kenneth Gardner, Dale Frost, Ian Tait, Kendal Morris, and
Erwin Caughman.
Much of the information in this booklet was derived from research completed at
Tijuana Estuary and several other wetlands. The California Sea Grant College Program
and the Marine and Estuarine Management Division of the National Oceanic and
Atmospheric Administration provided most of the funding for this research.

COVER PHOTO BY PAUL JORGENSEN

Illustration Credits
California Department of Fish & Game, p. 47
Lee Emke, p. 9
Judith Feins, pp. 15, 25 courtesy of the California Coastal Commission, California Coastal
Resource Guide, University of California Press, (D 1987
Julie Goodnight, pp. 30, 39
Anna Kondolf, pp. 5, 6, 7, 8, 11, 28, 39
Douglas W, Moore, pp. 27, 30
Kendal Morris, pp. 27, 32
Peter Moyle, p. 52 Inland Fishes of California, (0 1976. Reprinted by permission of University
of California Press
Pedro Salgado, p. 18
San Diego Unified Port District, p. 31
Deboyd Smith, pp. 24, 50, 64. A Guide to Marine Coastal Plankton and Marine Invertebrate
Larvae, (0 1977. Reprinted by permission of Kendall/Hunt Publishing Company.
Dena Smith, pp. 3, 10, 21
Judy Ward, p. 28

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