The Coastal San Luis Resource Conservation District (CSL RCD) began
working with Vard Ikeda of Ikeda Brothers Farming when the Dixson Ranch
was preparing for the Dixson
Ranch Agricultural Easement , which was awarded October, 2001. The
Ikeda Brothers are the farmers of record on Dixson Ranch. The Ikeda family
is involved in all aspects of their farming operation and are an integral
part of the Pismo Oceano Vegetable
Exchange (POVE). Please
click here to go to their website and learn more!
In addition to farming on Dixson Ranch, Ikeda Brothers Farming owns
and operates other farms in the Arroyo Grande Creek watershed. In
July 2001, Vard Ikeda took USDA-NRCS staff on a tour of the Ikeda Ranch,
located adjacent to Arroyo Grande Creek, to assess possible projects for
the Soil & Water Conservation Assistance (SWCA) program. Vard described
the erosion that occurred in his fields due to runoff during heavy downpours.
During heavy rains, runoff from rangelands and roads above his farm would
flow through culverts under county roads and onto his fields, scouring
away valuable topsoil and carrying it across neighboring farm fields and
continuing to scour all the way to Huasna Creek.
Vard had tried cover crops, but still had issues with erosion during
heavy storms. Several NRCS Staff Engineers suggested an Underground Outlet
practice, but the flatness of the Ikeda’s Prime Agricultural Land made
it difficult to design an Underground Outlet with enough of a drop in elevation,
to enable water to flow adequately from the intake to the outlet. The Underground
Outlet practice is traditionally designed to run along field roads, but
the lack of fall in elevation made that design impractical at the Ikeda’s
farm.
In early 2006, current NRCS Engineer Mark Barnett came up with the
idea to design the Underground Outlet to run diagonally across the Ikedas’
farm fields to an energy dissipating basin (Structure for Water Control).
This new concept allows the pipeline to fall the appropriate elevation
to provide drainage across the nearly flat fields, and also incorporated
the addition of lateral inlets to pick up the water from adjacent and "upstream"
fields.
The energy dissipation basin installed at the receiving end of the
drainage pipelines reduces water velocity and energy, so that the potential
for erosion is eliminated and the settling out of sediment is enhanced,
before the water overtops the rim of the basin and flows over a 40 by 100
foot vegetated filter strip, into a 20 by 100 foot area of restored upland
vegetation, and finally into the riparian area adjacent to Arroyo Grande
Creek. The basin is designed to allow access by backhoe for periodic
sediment removal.
Construction on this innovative project design was completed in 2006.
A total of 3040 feet of pipeline for the main Underground Outlet and 1580
feet of lateral Underground Outlet pipeline (with inlets) were installed,
providing drainage to a total of 380.5 acres of farmland.
Project Benefits: This project benefits the Ikeda Brothers farm
by reducing soil erosion during heavy storm flows, and by improving drainage
on the farm fields after heavy storms. The latter aspect decreases
the amount of time that soils are too wet to allow equipment access.
In addition, the incorporation of the energy dissipation basin and vegetated
filter strip reduce risk of erosion from storm flow drainage, and reduce
sedimentation of Arroyo Grande Creek.
Project Funding: Cost share funding was provided by a NRCS
Environmental Quality Incentives Program (EQIP) grant as well as SWCA
funding (no longer an active program), and through the Coastal San Luis
Resource Conservation District with funds provided by CA
State Coast Conservancy. Combined funding provided over 80% of
project costs and made this project feasible. Project support was
also provided through a grant from the State
Water Resources Control Board and US Environmental Protection
Agency (under Federal Non-Point Source Pollution Control Program Clean
Water Act Section 319H).
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