Water Resources Research Act Program

Details for Project ID 2014CA324B

Balancing salmon populations, aquatic biodiversity, and water resource needs during drought in coastal California

Institute: California
Year Established: 2014 Start Date: 2014-03-01 End Date: 2015-02-28
Total Federal Funds: $25,000 Total Non-Federal Funds: $6,083

Principal Investigators: Stephanie Carlson

Project Summary: Climate change and water withdrawals pose grave threats to stream biodiversity in arid and semi-arid regions across the world. Although many species in these regions have adaptations allowing them to persist through drought, the limits of these adaptations will be tested with increased societal demands for freshwater and climate change. Despite these looming changes, ecologists still know relatively little about aquatic communities in intermittent streams (which cease flowing during some portion of the year), or about the use of these streams by ecologically and economically-important salmonid fish species. These knowledge gaps are hampering our ability to design, implement, and evaluate the ecological benefits of water conservation projects. Throughout California, innovative water conservation strategies are being implemented in an effort to balance competing demands for scarce freshwater. In many watersheds, farmers and conservationists are working side-by-side to conserve winter rainfall in off-channel ponds in order to enhance summer dry season habitat for salmonids, but flow targets to guide successful project implementation are lacking. We will address these knowledge gaps by quantifying (1) low flow attributes across a diversity of stream sizes from intermittent headwater tributaries to mainstem perennial streams (including reaches where water conservation techniques are being employed), (2) the effects of flow intermittency and dry season habitat contraction on aquatic biodiversity and community composition, and (3) the effects of habitat contraction on salmonid distribution and dry season survival. These results will be a major step towards providing managers with flow targets to support aquatic biodiversity, including Pacific salmon, during drought.