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Helps Water-Scarce Southwest
By Marcia Wood
September 23, 2002
Cottonwood forests and willow
thickets that line the banks of the San Pedro River in southeastern Arizona
make a welcoming green oasis in an otherwise dry landscape.
Agricultural Research Service scientists
and colleagues from the United States and abroad are scrutinizing the natural
cycling of water through the San Pedro River Basin ecosystem. Their intent: to
provide the science-based information needed to ensure that the 130-mile-long
river will continue to supply ample water for people, plants and animals.
The collaboration, now in its sixth year, is known as SALSA, short for
Semi-Arid Land-Surface-Atmosphere research program. Findings from SALSA should
not only benefit cities, towns, farms, ranches, wildlife, industry and the
military in the San Pedro Basin, but might also be applicable to other major
river basins in semiarid ecosystems around the globe. That's according to
hydraulic engineer David C. Goodrich of the
ARS Southwest Watershed Research
Center, Tucson, Ariz.
Much of the SALSA research focuses on developing new ways to predict how
ecosystem changes caused by people or nature might affect the amount of water
which moves into and out of a vast aquifer that feeds the Upper San Pedro
River. The aquifer is relatively easy and inexpensive to pump. Not
surprisingly, it is the sole source of water for rural and city residents in
the basin and for the Fort Huachuca military base. Today, more water is being
removed from the aquifer than is being replaced by rainfall and seepage,
according to Goodrich.
SALSA investigations may lead to new and better ways to both balance the
basin's water budget and meet the needs of those who use the water. Details are
in the September
2002 issue of the ARS monthly magazine, Agricultural Research.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.