HR: 09:45h
AN: NB31E-06 [Abstracts]
TI: Evaluating ecological effects of small-scale agricultural diversions on stream flow in Coastal California
AU: * Deitch, M J
EM: mdeitch@uclink.berkeley.edu
AF: Department of Landscape Architecture and Environmental Planning, University of California, Berkeley
202 Wurster Hall, Berkeley, CA 94720-2000 United States
AU: Kondolf, G M
EM: kondolf@berkeley.edu
AF: Department of Landscape Architecture and Environmental Planning, University of California, Berkeley
202 Wurster Hall, Berkeley, CA 94720-2000 United States
AU: Merenlender, A M
EM: adina@nature.berkeley.edu
AF: Department of Environmental Science, Policy, and Management, University of California, Berkeley
145 Mulford Hall, Berkeley, CA 94720-3114 United States
AB:
In the absence of summer precipitation, grape growers in the California wine country often pump water directly from the
stream for frost protection, irrigation, and heat protection. Managers may not be able to evaluate the impacts of the many
small diversions on flow or anadromous salmonid habitat because of the uncertainty of human water needs. Building on previous research to predict diversion impacts on streamflow, we monitored flow in Franz Creek (a third-order stream draining 40
km2 in Sonoma County) to evaluate our model, and then measured water coverage in riffles and pools to quantify the
change in salmonid habitat that these diversions would cause. Our model reasonably predicted flow decreases from diversion
for frost protection: flow decreased by up to 80% on each cold morning, causing 50% riffle loss. Though it was not
indicated in our model, the loss of habitat on hot summer days (suggesting diversion for heat protection) was also dramatic:
levels dropped suddenly, reducing volume in intermittent pools by over 50%. Both changes in flow led to sudden reductions in habitat, suggesting that diversions are a major impediment to salmonid restoration in the region.
DE: 1803 Anthropogenic effects
DE: 1842 Irrigation
DE: 1860 Runoff and streamflow
DE: 1884 Water supply
DE: 9902 NABS Student Award Applied Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly