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. can be designed for gravity flow and intersecting drainage channels can be crossed without difficulty. Chances for failure of the system are reduced and greater protection is afforded to the surrounding environ- ment with a closed pipeline. If the disposal site is located at an ele- vation higher than the collector, a pump and pipeline are required. The disposal site should be located as close as possible to the salt source. Evaporation ponds are a possible means of disposal if a rela- tively level plot of land of sufficient size is available nearby. An evaporation pond system should have a storage capacity sufficient to hold the annual saline spring discharge, plus annual precipitation (rain or snow), plus volume of accumulating salt over the life of the project, and less the annual amount of water lost through evaporation. A series of evaporation ponds is desirable if sufficient level ground is '~vailable. Accumulated salts from evaporation will be concentrated in the last pond of the series. The other ponds would have decreasing salt concentrations, progressing from the last pond back toward the source, with the first pond having a salinity only slightly greater than the saline source. The first ponds in the chain could potentially provide habitat for waterfowl. The ponds with the highest salt concentrations could be hazardous to.waterfow1. w Ul I- (.D Dikes creating evaporation ponds should be high enough to afford protec- tion against overflow resulting from wave action and should provide storage of abnormally high amounts of precipitation. The dike system should also keep overland storm runoff from entering the evaporation ponds. Cost of pond construction will be less when ponds are located on ~ fine-textured soils. The bottom and sides of ponds must be sealed to eliminate seepage. Materials suitable for lining ponds are fine-textured soil (clay), bentonite, and man-made products (polyvinyl chloride-PVC or hypalon), The size of ponds may be reduced by the installation of an aeration system (sprinklers). However, this requires a power source, greater maintenance, and increased operation costs. Preliminary studies by WPRS indicate that evaporation rates are highly variable and are s i gnifi cant1y reduced as concentration of sa lts approach bri ne conditions. This could affect the size of ponds needed or even the viability of the use of evaporation ponds for salinity control. The deep well injection disposal process is only possible where geologic formations are porous enough to accept brine and yet not so fractured that brine would escape to contaminate freshwater aquifers. This pro- cess is currently being used by oil companies as a means of disposing of saline water, a byproduct of oil production. However, deep well injec- tion is a costly process. It requires an adequate supply of power to pump brine under pressures sometimes reaching 3,000 pounds per square inch (ps i) . It may also resul t in damagi ng envi ronmenta 1 side effects if brines leak into freshwater aquifers or pressure-caused earthquakes occur. B. .F10wing Wells Abandoned oil and gas exploration wells may penetrate a number of fresh- 17 ,;;'" . ~. - ,. ~ -<.-,,', -- ~-':~- ,~. . ; 1 ;f "1 , .,'j 1 -. ,- I ~ ~ 1 -1 ;:1 - ,-~ -"i