| OCR Text |
Show It is presently believed that some portion of the precipitated salt, approximating 180 million tons, has been redissolved by rainfall and removed from the pond by either Magcorp or by flow over the weir. Much of this has not, however, returned to the lake. This removal of salt has had an impact on the overall salinity of the lake. In its present configuration, the WDPP is capable of operating only at south arm lake levels of 4208 feet or higher. ( The WDPP operation is referenced to south arm lake elevation.) The current configuration of the WDPP will allow the pumping of only north arm brines. Pumping the denser north arm brines reduces the efficiency of evaporation, in that less water can be extracted from the brines before salts begin to precipitate in the West Pond. Operation of the WDPP should begin in the early spring as the lake begins its seasonal rise and continue through the summer evaporation season. Pumping should continue through the fall and into the winter to redissolve the salts left during the summer and return them to the lake. The relationship between lake levels, the pumping of brine from the north and south arms, and the build- up of salts in the West Pond are presented in Figure 7. The upper, more densely stippled shading shows the upper and lower limits of salt precipitation for north arm brines at varying lake level elevations. The lower, less densely stippled shading shows the same limits for south arm brines. Figure 7 shows that the WDPP could operate without precipitation of salts in the West Pond if operation is commenced only at lake elevations of 4210 feet above sea level and higher. With the current configuration of the inlet canal and West Pond, the WDPP can only be operated at lake levels above 4208 feet, with feed brine pumped from the north arm of the lake. Unless the West Pond is significantly reduced in size, which would significantly reduce the effectiveness of the system, operation of the WDPP in its current configuration will result in precipitation of additional salts in the West Pond. 36 |
