Cordilleran Section - 97th Annual Meeting, and Pacific Section, American Association of Petroleum Geologists (April 9-11, 2001)

Paper No. 0
Presentation Time: 10:30 AM


COLBURN, Ivan, Dept. of Geological Sciences, California State Univ, Los Angeles, Los Angeles, CA 90032,

One million acre-feet of agricultural waste water with salinity of 3.34 ppt annually carries 4.5 million tons of salt into the Sea. Since 1905 this process has changed the Sea from the largest fresh water lake by surface area in California to a hypersaline one with salinity of 44 ppt. The Imperial Valley and Coachella Valley Water Districts have obtained the right to sell 300,000 acre-feet per year of their unused Colorado River water allotment currently flowing into the Salton Sea to San Diego County Water Authority. This projects to a 30% reduction in runoff water and dissolved salt to the Sea. Moreover, there will be a drastic reduction in the Sea's water depth causing a significant shift of its shoreline toward the center of the Salton Trough. Also projected for the Sea is a rise in its temperature, a rise in its capacity for dissolving salt, an increase in its rate of evaporation, and a decrease in its level of dissolved oxygen. By 2010 the Sea's volume will have shrunk 78% and its tds increased to 221 ppt. To "save" the Sea requires finding a cost effective method of reversing the Sea's projected rising salinity and shrinking volume. If 25% of the Sea's water, amounting to 970,000 acre-feet, were removed, desalted, and then replaced in the Sea it would only change its salinity from 44 ppt to 33 ppt. Using the cost of operating the City of Santa Barbara's desalting plant of $1,300/acre-ft. the one time cost of desalting 970,000 acre-feet of the Sea's water would be one billion two hundred and sixty one million dollars ($1,261,000,000.00). Meanwhile, 3.15 million tons of salt will annually be added to the Sea from agricultural runoff water. The present-day geologic and man-made environmental conditions and the cost of desalting the Sea's water constitute an insurmountable obstacle to "saving" it.