Biology Reference
In-Depth Information
spread tree seeds, and engulfed fields—spurring the growth of fish food in
the warm shallows—is now constrained by levees and walls.
Humans now treat most of the watershed's rivers like pipes, instead of
allowing them to be the agents of variability that nature created, according
to Tim Ramirez, a river rat and former assistant secretary of water policy
with the state's Resources Agency. “We still talk about building new dams
because water is being 'wasted' by letting it spill from full reservoirs and
run down the river out to sea. But these 'spills,' the closest thing we have to
the small seasonal floods natural rivers once had, aren't a waste, but a great
benefit to the ecosystem and the fish,” says Ramirez.
Sierra
Nevada
Central
Valley
San Francisco
Bay
Pacific
Ocean
N
0
50
100 miles
Map 2. Watershed of San Francisco Bay, encompassing 40 percent of the state.
(S.F. Estuary Institute)
