Yolo Bypass Habitat Drainage Improvement Project

The project includes five major components that will enhance the Yolo Bypass Wildlife Area’s ability to manage wetland resources

The Yolo Bypass Wildlife Area Habitat & Drainage Improvement Project is led by Ducks Unlimited and supported by a coalition of partners, including California Department of Fish and Wildlife (CDFW), Yolo County, Yolo Basin Foundation, and the Metropolitan Water District of Southern California. The project includes five major components that will enhance the Yolo Bypass Wildlife Area’s ability to manage wetland resources and agricultural operations and is identified as the top priority in the Yolo County’s 2014 Yolo Bypass Drainage & Water Infrastructure Improvement. Project improvements will allow the CDFW to:

• expand the acreage of managed wetlands within the wildlife area.
• increase the productivity of existing wetlands.
• improve management for rice fields.
• reduce on-site flooding from the South Davis Drain.
• increase Department and public access to the Wildlife Area.

The design and permitting process is complete with construction scheduled to begin in 2020. Ducks Unlimited secured $2 million in funding to implement Project Components 1, 3, & 5 through the Delta Conservancy’s Ecosystem Restoration & Water Quality Proposition 1 Grant Program. In 2020, the Wildlife Conservation Board awarded Ducks Unlimited an additional $1.7 million for the same components.

Partners continue to seek project funding through state grant programs and CDFW's 2021-22 budget. The full benefits of this large-scale restoration project cannot be realized until construction of all Project Components is complete.

This project element will improve access to the wildlife area as well as drainage along the South Davis Drain by alleviating flooding at Rice Corner. The South Davis Drain’s capacity is constrained by the existing drainage culverts at the corner, which are blocked due to a variety of factors including vegetation and beaver dams. As a result, backed up drain flows inundate surrounding lands and flood access roads. This work will replace culverts and parallel road crossings with a single precast concrete bridge (Con-span) to improve capacity and accelerate drainage of the surrounding wetlands, rice fields, and roads. Several smaller culverts will also be replaced with larger versions and new water control structures added.

Green’s Lake functions as an irrigation reservoir and includes a channel that extends south to the South Davis Drain. This work will create flexibility by separating water drainage and water supply infrastructure near the lake’s current drainage channel. With these improvements, wildlife area farmers and wetlands managers will improve control of water flows. Water levels in Green’s Lake will be maintained when the South Davis Drain releases water through the wildlife awrea following a storm event, or in the fall/spring for management of the wetlands and rice fields.

Includes removing the two parallel road crossings over the South Davis Drain at the “Y” and replacing them with a single precast concrete bridge. The “Y” road crossing is a major constraint to draining the western side of the wildlife area. This crossing serves as the main access road for all agriculture operations, wetland management and public access north of the Putah Creek channel. Combined with the Rice Corner Con-span, work will improve the capacity of the South Davis Drain and includes culvert and channel improvements in three separate areas to improve flows between the channels. The excavated material from channel improvements will be side-cast onto the adjacent dirt road parallel to the channel and compacted in place to form a wider road improving maintenance access and increasing the ability to drain South Davis Drain water into the Toe Drain by way of the Cross Canal.

Construction will install a new water pump north of the Cross Canal in the eastern portion of the wildlife area. Floodwater in this area is difficult to manage due to a lack of adequate infrastructure. The new pump station will allow drawdown of rice fields and wetlands if there is minor flooding in March through June. It also includes roadway improvements that will increase access to the wildlife area and aid in separating Toe Drain flood waters from managed wetlands and rice fields.

Wildlife Area managers originally intended to convert a 220-acre area of land located directly south of the Parker Pond to managed wetlands but lacked water. By excavating a segment of the southern edge of the pond to create a sump, or low area, and adding a new water lift station, the pond’s water storage capacity will increase and allow managers to inundate the 220 acres on demand. The wetlands are currently only inundated with the Yolo Bypass floods and therefore are often dry.