Impact of multi-annual drought on streamflow and habitat in coastal California salmonid streams |
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| Authors: | Matthew J Deitch Mia Van Docto Mariska Obedzinski Sarah P Nossaman Andrew Bartshire |
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| Institution: | 1. Soil and Water Sciences Department, IFAS West Florida Research and Education Center, University of Florida, Milton, Florida, USAmdeitch@ufl.edu;3. Trout Unlimited, Emeryville, California, USA;4. Coho Salmon Monitoring Program, California Sea Grant, Windsor, California, USA |
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| Abstract: | The 2012–2015 drought in north-central coastal California ranks among the three most prolonged periods of below-median annual rainfall in the past 65 years. In three critical coho salmon streams, summer baseflow was less each additional dry year; streams with summer flow early in the drought had no flow for more than two months in latter years. By the third dry year, summer discharge was 1–5% of recent wet-type years, and 10–20% of the first dry year. Multiannual drought also caused increased dry channel conditions: the percentage of flowing channel reduced from 28 to 55% from the first to the third dry years among three study streams. In the first year following drought, dry-season streamflow resembled early to-mid-drought conditions, while in the second, it approached pre-drought discharge. This multiannual drought foreshadows how multi-annual drought predicted under future climate scenarios may affect critical salmonid streams later this century. |
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| Keywords: | California drought streamflow salmon conservation instream habitat Mediterranean climate temporal variability |
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