Central California’s steelhead populations have been decimated by the loss of habitat (development) and water diversions says a new University of California, Berkeley report:
“Nearly all of California’s salmon and trout populations are on the path to extinction and if we’re going to bring these fish back to healthy levels, we have to change the way we manage our water,” said lead author Theodore Grantham, a recent Ph.D. graduate from UC Berkeley’s Department of Environmental Science, Policy and Management (ESPM). “Water withdrawals for agricultural uses can reduce or eliminate the limited amount of habitat available to sustain these cold-water fish through the summer. I don’t suggest we get rid of vineyards, but we do need to focus our attention on water management strategies that reduce summer water use. I believe we can protect flows for fish and still have our glass of wine.”
The report highlights events like the sizable water withdrawals that occur during spring freezes, when water is pumped from streams to protect grapes (the water freezes on the grapes, minimizing thermal damage).
As much water can be used in a 2-3 day period than during the whole irrigation season.
And summer removals from streams already suffering reduced flows result in very low survival rates for juvenile steelhead.
How can water supplies be better managed for both fish and grapes?
One possible solution, Grantham noted, is establishing small off-stream reservoirs to store water during times of high rainfall. Vineyards would be able to draw from these water stores during low-flow periods rather than directly from streams.