The San Luis & Delta-Mendota Water Authority and Westlands Water District filed a lawsuit in federal court Friday to compel the U.S. Bureau of Reclamation to examine the effectiveness of the existing measures intended to protect endangered species, the environmental impacts of those measures, and whether there are alternatives to those measures that would better protect both endangered fish species and California’s vital water supplies.

The existing measures, adopted in 2008 and 2009, are based on biological opinions issued under the Endangered Species Act.