Proposal for Pilot Evaporation Pond

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Paradox Valley Unit Proposal for Evaporation Pond If the existing 10-inch pipe is no longer usable, a new 4-inch diameter PVC or HDPE pipe would be installed within the existing pipe. If this is not feasible,the new pipe could be installed alongside the existing10-inch pipe to deliver brine to the evaporation pond. During the design process,brine samples will be analyzed to measure types and concentrations of volatile organic compounds (VOC's) and other organic chemicals. A stripping plant or air stripping system will be incorporated if concentrations of VOC's are too high to disperse by natural ventilation and sunlight at the pond, or if they pose risk beyond acceptable tolerances and regulations for the environment,wildlife, or the public traveling by the vicinity. The stripping system would remove chemicals from the brine before it enters the pond and would be designed for the brine's chemical constituents, concentrations, and flow requirements. Depending on the results of the brine chemical analysis,a permit for the pilot evaporation pond may be sought without initially including a chemical stripping system. This could provide an additional component for test pond observations and would help in determining stripping plant needs for future larger scale evaporation pond operations that may be pursued. If a stripping system is not in- place upon commencement of test pond operations, a retrofit system would be added promptly, or pond operations abandoned, if unacceptable adverse conditions are observed at the pond that could be mitigated by a stripping system. Review of Evaporation Ponds and Migratory Birds at Great Salt Lake,Utah The Great Salt Lake Minerals Company's evaporation ponds adjacent to the Great Salt Lake in Utah cover 36,000 acres and have similarities to the proposed pond at Paradox in that they are both near the western boundary of the Central Flyway for migratory birds,have similar climates,have comparable brine composition(see Figure 5), and are close to a source of fresh water. The evaporation ponds bordering the Great Salt Lake have been in operation for many years. Two of the large evaporation ponds operated by the Great Salt Lake Minerals Company border the north arm of the Great Salt Lake, which is the area most visited by migratory birds. Despite the close proximity of the evaporation ponds,few documented negative impacts on the migratory birds have been identified. The birds appear to visit the fresher water areas of the lake that provide an appropriate habitat. The U.S. Geological Survey(USGS) identifies the Great Salt Lake as "one of the largest migratory corridors in Western North America." The USGS estimates that the Great Salt Lake supports between 2 and 5 million shorebirds, nearly 1.7 million eared grebes, and hundreds of thousands of waterfowl during the spring and fall migration. The Dolores River and other water sources near the Paradox Valley are not identified as supporting large migratory bird populations like those supported by the Great Salt Lake. However,the migratory birds that do pass through the 8