Clay Station Mitigation Bank

The Clay Station Mitigation Bank (CSMB) is located in southeast Sacramento County, California. Historically, the 405-acre site supported vernal pool grasslands, but following World War II, the land was converted to agricultural farming. ECORP conducted biological surveys and completed feasibility studies of the site to determine its potential for sustaining restored/constructed wetlands. Using historic aerial photos and current soil data, ECORP prepared a restoration plan that included over 90 acres of vernal pools, seasonal wetlands, and marshes. The CSMB was approved by the U.S. Army Corps of Engineers, the U.S. Environmental Protection Agency and the U.S. Fish and Wildlife Service to serve as off-site mitigation for impacts to wetlands/waters of the U.S. and habitat for federally listed branchiopod species including the vernal pool fairy shrimp (Branchinecta lynchi) and the vernal pool tadpole shrimp (Lepidurus packardi).

 

Wetland construction at the site occurred in two phases with Phase I completed in October 1994 and Phase II and Phase III completed in August 1999. ECORP prepared the wetland construction specifications, assisted in the bidding process, coordinated construction timing and methods with the client and contractor, and provided on-site monitoring during the wetland construction process. ECORP developed the Bank Enabling Instrument for the CSMB, the deed restrictions and conservation easement for the site, the Bank Service Area, the Bank Development Plan, and the Bank Closure Plan.

 

Following bank establishment and wetland construction, ECORP conducted the detailed success monitoring of CSMB. Each phase was monitored for five years for hydrology, invertebrates, and vegetation. The five-year monitoring program for Phase I wetlands was completed in 1999 and the five-year monitoring program for Phase II and III was completed in 2004. Monitoring showed that the constructed wetlands are functioning hydrologically and floristically as intended, and support both vernal pool fairy shrimp and vernal pool tadpole shrimp.

 

The site has entered its long-term monitoring and management phase. The site is zoned as Open Space Preserve, is protected by both a recorded conservation easement and a deed restriction, and is being managed in perpetuity by the Elliott Conservancy. The site is monitored annually by the Elliott Conservancy with annual reports of findings submitted to the U.S. Fish and Wildlife Service and the U.S. Army Corps of Engineers.

 

Since the creation of the CSMB in 1994, ECORP has assisted the Elliott Conservancy with the credit sales and credit availability tracking of the site. ECORP continues to assist the Elliott Conservancy with providing on-call assistance for this project.

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