The Department of Water Resources (DWR) has begun an innovative program in the San Joaquin Valley to help local levee-maintaining agencies implement flood control projects while preserving habitat for the endangered giant garter snake.
The “advance conservation” program identifies and sets aside habitat, in this case snake habitat, before agencies begin work that could result in the taking of threatened or endangered species or their habitat. DWR has invested $4.1 million of Proposition 1E funds and contracted with Westervelt Ecological Services to create a giant garter snake conservation bank that can ultimately be used by levee-maintaining agencies in the south Delta and the Stockton area south along the San Joaquin River to approximately Fresno.
Traditionally, project developers consider how they will mitigate, or diminish, the harm done to threatened and endangered species each time they work on a new project. However, this project-by-project approach results in piecemeal conservation that can take time, be costly and result in small and fragmented habitat that short-changes the species it was meant to protect.
Mitigating in advance allows for a landscape-scale approach for offsetting environmental impacts and allows for more efficient project approvals, more certainty to cost estimates and takes advantage of conservation opportunities before important habitat is lost to other activities. Advance conservation reduces delays in infrastructure improvements and repairs, especially when conservation lands cannot be easily located or purchased.
Under the advance conservation program, a contract for the creation of credits is purchased from conservation banks, which permanently protect and manage lands with natural resource values. In exchange for permanently protecting lands under certain criteria, permitting agencies such as the U.S. Fish and Wildlife Service and the California Department of Fish and Wildlife approve a number of credits that can be used to offset adverse impacts to habitat or species within a defined “service area” for the bank.
Planning in advance allows DWR to participate in the development of the conservation bank and the purchase of giant garter snake credits in bulk, which lowers the cost of the individual credits approximately 30-45 percent. Because the conservation is planned in advance and combines the needs of multiple infrastructure projects into one area, the bank can achieve improved connectivity, larger preserves and better conservation for the species at risk, which is the premise behind the “landscape-scale” approach.
The Grasslands Mitigation Preserve is located in Merced County near Volta Wildlife Area, which houses the largest known breeding population of these snakes in the San Joaquin Valley. This project should be able to serve all of the giant garter snake mitigation needs for the State Plan of Flood Control in the San Joaquin Valley and levee projects in the southern portion of the Sacramento-San Joaquin Delta. It was jointly funded under DWR’s Central Valley Flood System Conservation Framework and Strategy and Delta Levees programs.
The giant garter snake lives in wetlands and other shallow waterways such as irrigation canals, sloughs, ponds and levee toe drains and uses ground squirrel burrows for escape and to overwinter. Much of the snakes’ natural habitat has been lost or fragmented due to development.
A multi-agency project team comprising personnel from DWR, California Department of Fish and Wildlife, U.S. Fish and Wildlife Service, U.S. Army Corps of Engineers and National Marine Fisheries Service recognized a need for a project in the San Joaquin Valley that would mitigate for flood infrastructure impacts to giant garter snakes.
The Grasslands Mitigation Preserve will be one of DWR’s first advance conservation efforts funded under Proposition 1E and the 14th giant garter snake preserve for which Westervelt’s staff have planned and permitted, designed, managed construction and prepared long-term stewardship plans.