By Scott Holmes
Wednesday,
June 22, 2005 - The City of Pacifica is committed to the restoration of San
Pedro Creek and its watershed. Over the last five years, approximately 15 acres
of riparian habitat, wetlands, and tidal lagoons in the watershed have been
restored. The first successful project that the City completed in the watershed
was in the year 2000 when the Army Corps of Engineers assisted the City and
provided almost $7 million in funding to construct the lower Linda Mar Flood
Control Project.
Most recently, the City and the Corps of Engineers
restored four acres of tidally influenced wetlands at the mouth of San Pedro
Creek. Steelhead are now thriving in the lower reaches of the creek and with
over 50,000 new trees planted, there has been a noticeable increase to the bird
population. Over 75 bird species have been counted with many new to the area. An
important project benefit has been the tremendous improvement in flood
protection, benefiting over 300 houses and businesses, and resulting in a
significant reduction in flood risk. With a few more projects sponsored and
funded by the Corps, Caltrans, etc., the lower Linda Mar Valley will one day be
protected from the threat of the 100-year flood interval. The Corps has been an
excellent partner to the City assisting with flood control and stream
restoration since 1975. The City owes the Corps and its dedicated employees a
tremendous note of gratitude for all of their hard work.
In 2001, the
City of Pacifica attempted another partnership with the Corps through a program
to restore creek banks and wildlife habitat in the Capistrano Avenue reach of
San Pedro Creek. The City and the Corps made considerable progress on the
project until 2003 when the Corps experienced severe Federal Budget cuts and
could no longer assist with funding the Capistrano Project. The City anticipates
that funding from the Corps will return and at some point, the City and the
Corps will resume their partnership in the restoration of San Pedro Creek.
Subsequent to the Corps withdrawal from the project, the City decided to proceed
in obtaining approximately $2 million in grants to complete the project.
In continuation of these ongoing effort to restore the creek, Pacifica
is in the process of eliminating an existing barrier to fish migration at the
Capistrano Bridge crossing while restoring approximately 2,000 linear feet of
riparian habitat along the creek banks. The reach up and down stream of the
Capistrano Bridge is of special concern, as segments of channel are heavily
developed and suffering from severe bank erosion and habitat degradation.
Restoration efforts are circumscribed by concerns over flooding and the
protection of private property.
The need for the Capistrano Fish Passage
Restoration Project originated with the construction of the Capistrano Bridge in
the late 1930's when the long term affects of its design were not known. This
section of San Pedro Creek was also channelized during early agricultural
development of the valley and was then further restricted to its current
location by residential development in the early 1950's. San Pedro Creek also
has dramatic peak flows that originate in the upper watershed, an environment
that has almost rain forest-like characteristics. Typical rainfall in the back
of San Pedro Valley averages over 50 inches per year. As many of the long time
residents can attest, heavy rainfall can turn San Pedro Creek into a raging
river with enough capacity to transport large boulders, houses, bridges and cars
down its channel. Peak flows in the creek can be as high 3,000 cubic feet per
second (equivalent to a swimming pool per second and an average high flow
similar to that of the American River in the Sierras). Channelization of the
creek forces it to remain in the same location with no where to erode but
downward. In many areas, the creek has down-cut over 15 feet. This has caused
the banks of the creek to fail. It also provides poor habitat for fish and birds
and threatens private property.
Unless restored, some areas of creek
could down-cut another 20 feet. This additional 20 feet of erosion will result
in the loss of private property and even homes. During the winters of 1998-1999,
high creek flows caused 5 to 6 feet of down-cutting at the Capistrano Bridge,
undermining the bridge footings.
The bridge remained closed for over two
years while emergency permits were obtained for its temporary repair.
Down-cutting at the Capistrano Bridge has restricted the migration of steelhead
from the lower reaches of the stream to the upper spawning habitat. Currently
the Capistrano Bridge serves as a 16-foot barrier to fish migration. The City is
at risk of losing an entire population of steelhead if this problem is not
addressed.
For the last seven years, the City has worked to complete the
restoration design for the Capistrano Fish Passage Restoration Project. In doing
so, the City has held a series of public meetings and has incorporated input
from creekside residents, volunteers from the San Pedro Creek Watershed
Coalition, the Corps of Engineers, California Department of Fish and Game,
National Marine Fisheries and professionals in stream geomorphology, hydrology
and habitat restoration. The project is a product of community teamwork. The
City is currently working with adjacent property owners for the permission to
construct the project and complete the permit process.
The City
anticipates obtaining the permits by the end of July and beginning construction
in August. The project will be constructed in two phases. The lower reach up to
1,000 feet below Capistrano Bridge will be constructed this summer if the
permits are obtained. If not, this reach will be constructed next year. The
upper reach will be constructed next year.
During construction, the City
will remove the fish barrier at the Capistrano Bridge crossing and the degraded
channel will be reconstructed to have more gentle banks, a wider channel and
terraces for better habitat. The channel bottom will be restored to its 1950
grade (approximately 15 feet higher to allow the fish to migrate upstream to
historic spawning gravels) and a natural-looking step-pool/run complex will be
installed using large rock weirs (structures crossing the creek). Large pine
trees and root wads will be placed in the channel for bank stabilization and
habitat enhancement. Where necessary, rock planted with native species will be
used to stabilize the banks. Approximately six species of native trees and
approximately 20 species of native plants will be planted, a total of
approximately 30,000 plants native to the area.
Once the project is
completed, the creek will have adequate flood control and the banks will be
protected. The project will also reduce streamside erosion by stabilizing the
stream banks through applied natural processes. The fish population will
flourish and the creekside residents will be able to walk down to the stream to
enjoy its beauty.
Currently, most residents encounter a 10 to 15 foot
vertical drop to the streambed. The residents have been great to work with and
the City plans to work closely with the residents throughout the length of the
project. This is the same process that was followed in the lower Linda Mar Flood
Control Project. The habitat enhancement for both animals and people has been a
tremendous success. If you would like additional information on this project or
information about other possible projects in the creek, please contact Scott
Holmes with the City Public Works Department at 738-4660. Feel free to request a
tour of the construction once it begins.
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