© 1997, 1998 Streamline
Publications
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SIMI VALLEY SITS at the head of Ventura Countys 350
square-mile Calleguas Creek watershed. The opposite end of the
waterway empties into Mugu Lagoon and the Pacific Ocean (see article
on Mugu lagoon).
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Concern over exactly what the creek carries to the sea has prompted
California state water quality regulators to issue an order for cities
and county agencies to identify and map the sources of pollution that
end up in the environmentally sensitive lagoon.
In August, 1998, the planned three-year Calleguas Creek
Characterization Study, as the monitoring effort is called, began
monthly water tests at eighteen points along the creek and the
tributaries feeding it. An additional twelve underground sites
(aquifers) will also be tested. The various pollutants will be
identified to help pinpoint their sources. Agricultural pollutants
will be distinguished from urban runoff that contains contaminants
such as animal waste and motor oil.
dichloro-diphenyl-trichloro-ethane
Concern over pesticides stems from their widespread use on farms.
DDTa compound employed worldwidehad also been used
extensively by farmers and by the Navy at its Point Mugu base until it
was banned in the 1970s. DDT was linked to the near extinction
of the brown pelican and other birds native to the lagoon. (Mugu
Lagoon is a stopover for migrating birds as well.) The pesticide has a
life of 50 to 100 years before it breaks down. Scientists have found
DDT at depths of two feet in Mugu Lagoon sediments and expect that it
may be present as deep as 30 feet.
In this muddy containment, the DDT has less impact on the food chain
and as a result brown pelican numbers are growing. Yet, mussels, clams
and certain fish contain elevated DDT levels and are unsafe to eat.
The concern is heightened because of the ocean erosion which chews
away at the sediment releasing the pesticide and other pollutants.
Other
Nasty Stuff
The creek and lagoon contain more than a dozen pesticides,
herbicides and chemicals that present risks to humans and the
environment. Because of cleanup efforts quantities of three toxic
metals and PCBs have been reduced in the lagoon to levels thought to
be safe. However, any comprehensive plan to eliminate or mitigate the
pollution is years away. The problem is difficult because no one can
be sure what actions might correct the problem without causing an even
larger difficulty.
The Characterization Study, which is a key part of the larger
Calleguas Creek Watershed Management Plan, takes the early, necessary,
step of identifying the scope and complexity of the pollution as well
as its various sources. In the meantime, the U. S. Navycustodian
of the lagoonwill continue to monitor the populations of
threatened and endangered species.
Erosion
and Pollution Prevention
Various federal programsnow in place and under developmentprovide
monetary incentives for habitat development on agricultural lands. Use
of cover crops, buffer strip plantings and other techniques that will
reduce farm runoffand the amount of pollutants entering the
creekare part of the answer. Some of these programs face funding
problems and tend to lose their attractiveness to farmers because of
complicated and competitive application processes.
The state Coastal Conservancy has provided $305,600 for bank
stabilization along a tributary of Calleguas Creek. The money is
related to a $52 million federal plan to reduce by two-thirds the
sediment entering the creek. Revegetation, rather than concrete, will
be used in the erosion control effort that will receive additional
grants and contributions from landowners.
While the pollution in Mugu Lagoon is studied, natural forces
continue to work on the salt marshto what end, man can only
guess.
See also Mugu Lagoon: A
Study in Erosion.
Read about endangered
plants and politics.
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