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<br />DELTA WETLANDS
<br />
<br />The Delta is the connecting point for the entire
<br />Central Valley hydrologic system, California's two
<br />longest rivers, the Sacramento and the San Joaquin,
<br />join in the Delta region and mix with salt water flowing
<br />east from San Francisco Bay. The huge water
<br />volumes that naturally coursed through the Delta
<br />created hundreds of thousands of acres of wetlands
<br />that supported an abundance of diverse life forms,
<br />many uniquely adapted to the Delta environment and
<br />its flow cycles, In the 1800s, the most visible
<br />vegetation were tules, reeds that sometimes reached
<br />15 feet in height, but riparian vegetation such as
<br />willow trees and shrubs also was present. About 87
<br />percent of the 500 square miles of Delta area are
<br />estimated to have been intertidal wetlands at one time.
<br />
<br />Delta wetlands acreage began to decline shortly aher
<br />the Gold Rush, when farmers drained marshy areas
<br />and built levees around low-lying areas and islands.
<br />By 1930, almost 500,000 acres of farmland were
<br />guarded by 1,000 miles of levees, Bigger changes
<br />came in the 1940s and 1960s, when the CVP and
<br />SWP were constructed, altering the historic water
<br />flow patterns that supported Delta wetlands,
<br />
<br />CALFED has made restoration of Delta processes
<br />and ecosystems, including wetlands, a key part
<br />of its efforts to find a consensus solution
<br />to California's water problems. It wants to
<br />reestablish frequent inundation of floodplains by
<br />removing, breaching or setting back some levees
<br />and increasing the extent of freely meandering
<br />rivers. It also proposes to increase areas of
<br />tidal marsh by removing or breaching levees and
<br />raising the elevation of subsided, leveed former
<br />marshlands.
<br />
<br />CALF ED planners take a different view of
<br />flooding than did the engineers and farmers who
<br />built the Delta's flood-control apparatus.
<br />Recognizing that some flooding is inevitable,
<br />CALFED's plan calls for removing selected
<br />dams, breaching levees and using bypass
<br />channels in ways that manage flooding more
<br />naturally and reap some of its ecological
<br />benefits. Giving rivers more access to their
<br />floodplains would help restore wetlands while also
<br />reducing high flow velocities that weaken levees,
<br />according to CALFED,
<br />
<br />CENTRAL VALLEY WETLANDS
<br />
<br />Wetlands in the Central Valley once covered an
<br />estimated 4 million acres from Willows in the north
<br />to Bakersfield in the south, but only about 10
<br />percent of that area remains today. The Central
<br />Valley wetlands historically provided habitat for
<br />numerous indigenous species, and were an
<br />important link along the Pacific Flyway for migratory
<br />birds and waterfowl.
<br />
<br />Beginning in the 1990s the trend of diminishing
<br />wetlands in the Central Valley began to reverse, and
<br />more acreage is being set aside for wetlands.
<br />Between 1993 and 1996, wetland acreage increased
<br />from 450,000 acres to 529,000 acres, and Califor-
<br />nia set a goal of increasing wetlands an additional
<br />225,000 acres by 2010,
<br />
<br />Restoring Central Valley wetlands will take commit-
<br />ments from a wide array of interests, including
<br />federal, state and local governments, farmers, water
<br />agencies and environmentalists. Up and down the
<br />valley, there are examples of such partnerships, such
<br />as fhe Central Valley Habitaf Joint Venture, which
<br />aims to protect or restore enough wetlands and
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<br />productive farmland to support 4,7 million migratory
<br />waterfowl that winter in the valley, Wetlands mitigation
<br />banks authorized by a 1993 state law allow public
<br />and private developers to compensate for adverse
<br />impacts on wetlands in one area by buying or
<br />restoring wetlands in another area.
<br />
<br />The CVPIA also is playing a role in Central Valley
<br />wetlands restoration. Through the act's environ~
<br />mental water guarantee, it firmed up water deliveries
<br />for environmental purposes and increased annual
<br />water supplies to federal and state waterfowl refuges
<br />that receive CVP water and to areas such as the
<br />75,OOO-acre Grassland Resource Conservation
<br />District near Los Banos. Under an agreement
<br />between the Bureau and the San Luis Delta-Mendota
<br />Water Authority, a 28-mile section of the San Luis
<br />Drain (now called the Grassland Bypass) normally
<br />used for agricultural drain water was reopened to
<br />supply clean water to wetlands at the San Luis
<br />National Wildlife Refuge Area, Renewed through
<br />September 2001, the agreement avoids sending
<br />agriculfural drain wafer contaminated with selenium
<br />to the wetlands,
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