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. Spoils. Three ueLls that are used for monitoring eater quality in the spoils above the <br />Wadge Impoundment are 25-5, 26-5, and 27-5. Weli 25-S, [he upper spoils well, did not <br />have enough eater in its casing to sample this year, although in the past it displayed a <br />MgCa-S04 type water. Well 26-5, the middle spoils eel 1, displayed a MgCa-S04 type eater. <br />Well 27-5, the Loner spoils cell, also displayed a MgCa-504 type water. TDS decreases as <br />one progresses doungradient- This is probably due to the diluting effect of the loner TDS <br />Wadge Impoundment ua ter in direct communication with spoils aquifer water. Year to year <br />trends in TDS are difficult to delineate probably due to the effects of fluctuating Wadge <br />reservoir eater levels- <br />Seven spoils wells were completed in the summer of 1987- Three (Wells 59-5 to 61-5) were <br />completed above Spoils Spring #3 (also known as the Spring Creek area). Four (Wells <br />62-5 to 65-5) were completed above Spoils Spring #1 (also known as the Cow Camp Creek <br />area). Starting in 1990, the furthest downgratlient well in each area was sampled for <br />water quality (Wells 61-5 and 62-5). Data collected by PCC and the U.S. Geological Survey <br />(USGS) in prior years indicate that eater quality from the spoils cells in each respective <br />area are similar. Well 61-5 displays a MgCa-S04 type water, while Well 62-5 displays a <br />LaM g-504 type eater. Average TDS values for Well 61-5 decreased 6y 145 mg/t this year, <br />chile average TDS values for Well 62-5 continue a slight increase since monitoring began. <br />Comparison of Ground Water Quality to Water Use Standards. The Colorado Department of <br />Health (CDOH) drafted basic standards for ground uate r, including standards for <br />agricultural use (i.e., livestock and irrigation). These standards have been summarized <br />and are presented in Table 11 (Appendix A). Parameters denoted with an asterisk on this <br />table pertain to livestock standards, while those not asterisked pertain to irrigation <br />standards- Results of analyses performed on samples obtained from monitoring cells during <br />the 1991 water year have been compared to these standards, and the comparison results are <br />presented in Table 12 (Appendix A)- <br />Table 12 shoos that Alluvial Wells 6-A, 32-A, 33-A, 46-A, 31-A2, 68-A, and 69-A; Wolf <br />Creek Overburden Well 7-WCO and Spoils Wells 26-5, 27-5, and 61-S all exceed the <br />irrigation. dissolved manganese standard of 0.2 mg/l. This standard applies to crops groan <br />in soils with pH values lower than 6-0. In soils with a higher pH (as is found in <br />agricultural soils surrounding the Seneca lI area), a more realistic standard could be 10 <br />mg/l (EPA, 1976). <br />The irrigation dissolved iron standard of 5-0 mg/L was exceeded at alluvial WeIL 32-A. <br />9 <br />