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Free-Water Surface Evaporation Rates In/Around The Anza-Borrego Desert
This page should not be necessary. It would not be but for the fact that some members of the BWD Board of Directors and at least one architect in Borrego believe, or at least claim, that water surface evaporation from swimming pools, spas, etc., is not a serious source of water loss in the Anza-Borrego Desert. To refute this pernicious and counter-intuitive notion, and in case anyone else should be foolish enough to subscribe to it, we are providing the following information:
http://www.werc.usgs.gov/mojave-symposium/abstracts.html
Many factors define an area's climate, but free-water surface evaporation is
an excellent indicator of the climatic variables that also partly control
transpiration of plants, such as solar radiation, air temperature, and wind.
Annual free-water surface evaporation along the Mojave River ranges from
about 60 to 85 inches.
http://www.serg.sdsu.edu/SERG/techniques/microcatch.html
Rainfall and Climate of the California Deserts: In all areas, the
potential evaporation far exceeds the average precipitation. In 1975,
at the United States Date Gardens at Indio, for example, total
precipitation amounted to only three inches (76mm), while free
evaporation (from an open pan) was 112.96 inches (2869 mm), more than
forty times the years of precipitation (Lenz, 1981).Most of the Colorado
desert (Coachella Valley and related area) normally receives less than five
inches (127 mm) of rain per year.
http://www.waterboards.ca.gov/coloradoriver/documents/board_orders/year_2002/02-012wdr.pdf
Blythe - Riverside County
The California Regional Water Quality Control Board, Colorado River Basin
Region finds that: The annual precipitation in the area is
approximately3.6 inches and the average temperature is 73.6 degrees
Fahrenheit. The evaporation rate is approximately 90 inches annually.
http://www.eh.doe.gov/nepa/docs/deis/eis0365/chapter_3-2.pdf
Because the Salton
Sea is situated in a closed basin, water flows into it but does not
leave, except by evaporation. The evaporation rate is about 6 ft/yr (2
m/yr) (Ponce et al.2003).
Ponce, V.M., et al., 2003, Modeling Salinity Balance in
Proposed Salton Sea Restoration Using a
Diked Impoundment,
San Diego State University, San Diego, Calif. Available at
http://attila.sdsu.edu/~ponce/saltonseapaper.pdf
http://www.usbr.gov/lc/region/saltnsea/deis/07-Chapter_3_part_1.pdf
The Salton Sea has no outlet. With an
evaporation rate of 5.78 feet per year, the entire volume of the
Salton Sea, with its maximum depth
currently at about 50 feet, would evaporate within about 10 years if all
inflow sources were stopped.
08/18/2006