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two million acres of woodlands, wetlands, and deserts. In the 1920s, natural-
ist Aldo Leopold paddled through the “endless green lagoons” (p. 150) of the
Colorado River delta to the Gulf of California. Yet today, 93 percent of the
delta's wetlands and woodlands have been reduced to a barren, unproductive
mudl at.
Major impacts are felt even beyond the delta, in the Gulf of California
itself, where the Colorado River once emptied, bringing nutrients, freshwa-
ter, and sediments and supporting a prolii c marine ecosystem. Freshwater
and saltwater mixed in this region for thousands of years, forming rich nurs-
ery grounds for i sh, shrimp, and waterfowl. But, along with the Colorado
River, marine life in the northern Gulf of California has suf ered a major
decline. Researchers at the University of Arizona have studied changes in the
abundance of the Colorado delta clam ( Mulinia coloradoensis ), a species that
once l ourished at the outlet of the Colorado River in the gulf. h ese clams
provide a measure of ecosystem health, and research shows that, a thousand
years ago, these clams were at least twenty times more abundant in the Gulf
of California than they are today.
h
e Sacramento-San Joaquin Delta
h e Sacramento-San Joaquin Delta is the hub of California's water distri-
bution system and has been at the center of controversy among environ-
mentalists, farms, i shermen, and cities in the state for four decades. Once a
700,000-acre tidal freshwater marsh, the delta has been gradually converted
into a network of channels and islands that limit i sh habitat. Moreover, riv-
ers upstream have been impounded behind reservoirs and diverted for agri-
culture and cities, causing further declines in the delta's habitats. Pumping
of water in the southern delta to the San Joaquin Valley farms and Southern
California via the California Aqueduct has caused currents in the delta to
reverse toward the south, rather than l owing west into the San Francisco Bay
and out the Golden Gate. h ese currents pull small i sh toward the southern
delta, entraining and killing thousands of endangered delta smelt and juve-
nile chinook salmon. h e delta smelt is endemic to the delta and has been
declining since 1990. At er 2000, the smelt declined even further as pumping
through the delta increased.
In the early 1980s, one proposed solution to these problems was the
Peripheral Canal, a forty-three-mile, concrete-lined channel that would have
linked the Sacramento River directly to the California Aqueduct. In 1982,
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