Audubon California has been implementing the following conservation projects with watershed farmers and ranchers. The Yolo County Resource Conservation District (Yolo RCD) {link to www.yolorcd.ca.gov} webpage and publication "Bring Farm Edges Back to Life!" also provides additional information, including guidelines for implementation and cost estimates, for many farm and ranch conservation practices.


Vegetating irrigation canals with native plants

To keep irrigation canals free of weeds, farmers and the agricultural irrigation districts typically scrape, spray or cultivate field edges to minimize the establishment of weeds. As an alternative, canal banks can be vegetated with native perennial plants to create a rich biodiverse corridor with multiple benefits of: suppressing weeds and thus reducing herbicide use; minimizing soil erosion thus reducing maintenance; and enhancing wildlife values and aesthetics. If possible, the slope to be planted should be regrading to a more gentle slope to ease planting and maintenance. The bank is then harrowed or disked and then seeded with native perennial grasses. The water edge is plug planted with native sedges and rushes. A vigilant weed suppression effort the first year after planting is crucial for successful establishment of the native vegetation.

Construction of tailwater ponds

Runoff from field and pasture irrigation can result in a series of problems. Silt-laden runoff from summer irrigation and winter storms removes topsoil, which is deposited downstream in unwanted places. Water runoff also impacts roadside ditches that must be constantly maintained by public work crews and adds to non-point source pollution in larger watercourses. Finally, unrestricted runoff results in a loss of water that might otherwise be reused or recharged to groundwater. The construction of a tailwater pond that catches and stores some or all of the runoff is an effective way to avoid these problems. A double-pond system works by making the first small pond a sediment trap for topsoil that can be excavated and reused on the fields. The second, larger pond serves for multiple purposes of water storage, ground water recharge, water return systems, and plant and wildlife habitat.

Habitat enhancement on riparian corridors and stock ponds

Historical stream channel management in the watershed has left us with mostly narrow, thinly vegetated streams that support little wildlife and are unable to carry the high flows of winter storms. Bare, eroding banks provide substrate for noxious weeds such as Yellow starthistle, Giant reed, and Himalayan blackberry, and contribute to sediment, which is carried downstream. Re-establishment of native vegetation along streambanks serve multiple functions of stream bank stabilization, weed suppression and wildlife habitat. Regrading banks to a more natural benched slope increases the flood capacity of the stream while making room for establishing native vegetation. In rangeland sites, riparian areas or stock ponds can be fenced to manage access to livestock. Carefully prescribed grazing can be used to manage for weeds within a revegetated area. Solar-powered off-stream or off-pond watering systems can be used to supply drinking water to livestock.

Rangeland enhancement through prescribed burning and native perennial grass establishment

Noxious rangeland weeds such as medusahead, yellow star thistle, and goat grass have infested large areas of the upper watershed of Willow Slough. These species decrease forage quality, interfere with grazing, and compete with native grasses and forbs and other desirable forage species. Appropriately timed prescribed rangeland burning in the upper watershed area can: 1) remove the dense mulch layer produced by exotic annual grasses, encouraging the regeneration of native species and more desirable forage species; 2) eliminate the yearÕs seed production of target exotic weeds, such as medusahead and yellow star thistle, and consequently reducing their seed banks; 3) release available nutrients, 4) favor the native grasses such by enhancing tillering and fragmentation of "decadent" native bunchgrasses. Prescribed burning also can be used to remove thatch to prepare a grassland area for seeding with native perennial grasses. Native perennial grasses provide important ecosystem functions in rangeland systems. Their deep and complex root systems help stabilize the soil and can tap water from deep in the soil profile, providing channels to improve rain infiltration and groundwater recharge. Many perennials stay green longer into the summer than annual grasses, and green up sooner in the fall, offering palatable forage for wildlife and livestock at times when it is most needed.