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CHAPTER IV ALTERNATIVES . W .4 CD (<) control syst~m would monitor the unit facilities. Transmission lines would be constructed to provide power for the pucp stations and the col- lector wells. Construction and permanent operating facilities would be located near the evaporation pond area and in Glenwood Springs. Measures would be implemented to mitigate losses to wildlife and cultural re- sources which would result from development of this alternative. Imple- mentation of Alternative DG would result in an annual salt load reduc- tion of 287,000 tons to the Colorado River. Unit Features Collection system.--A total of 11.8 ds of saline flows with an average salinity of 9,545 mg/L would be collected near Dotsero. About 4.8 cfs of the total would be collected from four of the eight irlentified springs, and 7,0 cfs would be collected by pumping saline ground water from wells in the area of the remaining surface springs. . Flows from two springs--Dot 9 and Il--would he collected usin.'!; sur- face diversion spring boxes with dikes. The boxes would be protected from Colorado River high flows by concrete cutoff walls behind the dikes which would tie into the riverbanks. The spring boxes would be precast concrete vaults with a gravity outlet line of polyvinyl chloride (PVC) pipe, A manhole would be installed to provide access to the boxes. Approximately 1.8 cfs would be collected from Dot 9 and I,) cfs would be collected from Dot II. For collection at Dot 10, which has somewhat diffuse flows, a per- forated PVC pipe system would be installed. To prevent intrusion of fr~sh water, this system would be covered by an impermeable PVC membrane over an area of about 15,000 square feet. A PVC gravity line would intercept the flow from the perforated pipes and would be controlled through a precast concrete manhole. About 1.0 cfs would be collected at Dot 10. Presently, flows from Dot 90 are intercepted adjacent to 1-70 and above the Colorado River and enter the river through two culverts under the highway. With implementation of Alternative DC, the culverts would be lined with polyethylene material to extend their service life, and culvert flow would be diverted through manholes into the conveyance pipe- line as discussed later. Approximately 0.7 cfs would be collected ~t Dot 90. . A well field consisting of thirty-one 6-inch wells drilled to a depth of 100 feet would collect subsurface saline flows near Dotsero, The wells would be cased and cemented as necessary to prevent mixin~ of surface and ground water, Twenty-six 2-horsepower (hp) and five S-hp pumps would collect a total of 7 cfs of water. The collection systel'l would have an annual energy requirement of 499,000 kilowatthours (kWh). The well field would preclude the need to collect the four rerM.inin~ surface springs. 21