Biology Reference
In-Depth Information
Downstream of these rivers in the delta, very little natural marsh or river
floodplain remains in today's network of canals, cutoffs, and diversions
built to deliver water. “Historically the delta had very diverse habitats, and
any organism adapted to living there had a lot of choices,” says Stuart Sie-
gel, a scientist who has contributed to many generations of delta restora-
tion visions. “If you were a fish, you could always find more than one spot
that worked for you.”
Scientists and resource managers are bringing variety back to the delta
in two ways: improving the “shallows”—shoals, dead-end sloughs, season-
ally flooded areas—that grow food and nurture fish, and connecting im-
proved habitats.
Migrating birds over Central Valley wetlands. (Courtesy of Natural Resources Con-
servation Service)
Even temporary and artificial shallows can be a magnet for fish. Take
the example of the 84-square-mile Yolo Bypass. The bypass is a vast area of
farmland on floodplain into which the Sacramento River can overflow
during winter storms, and then rejoin its main stem via Cache Slough (see
Map 12, p. 220). Scientists view the Yolo-Cache Slough complex, and the
two already-flooded islands at its heart, as one of the delta's most promis-
ing candidates for restoration. After floodwaters broke through the Lib-
erty Island levee in 1998, 500 acres of tule marsh grew on the site. Here,
in the least-subsided edge of the delta, scientists envision creating a
