Laserfiche WebLink
July 79, 1968. Comparison of this years' flows to prior years is not made since the <br />operation of the truck wash system tends to influence the natural flow conditions at Pond <br />003. <br />Review of Table 18 (Appendix A) shows a dramatic shift in water quality from 1985 through <br />1989. Prior to the truck wash operation, the average annual TDS of the floes at NPDES 003 <br />ranged from 1,225 io 1,578 mg/l. After the truck wash operation, the TDS range increased <br />to 2,491 to 3,028 mg/l. The water remains generally a MgCa-S04 type, although the <br />percentage of sulfates have increased approximately 21 percent, and bicarbonates have <br />decreased since the beginning of the truck cash operation. This water, as one would <br />expect, is of similar quality to that found at NPDES 002. <br />Surface water Site Sw-S2.2. This site is the furthest downstream surface water site in <br />the Little Grassy and Grassy Creek drainages prior to exiting the permit area. Therefore, <br />it is the most significant monitoring site with respect to shooing the cumulative effects <br />of mining in this area. Review of the hydrog raph of monthly flow measurements again shows <br />the lower than normal flows for the past four years due to drought conditions. <br />Pater at this site is a MgCa-S04 type. Table 19 (Appendix A) shows that TDS values have <br />generally increased over the period of record. During the last four years, increases in <br />mean TDS are largely attributable to changes in annual precipitation (lower), and slightly <br />higher contributions to TDS loads from truck wash operations associated with the 003 pond. <br />Scrinas. <br />Springs #1, 2 and 3. These springs all exist along the Northwest Diversion Ditch (see <br />Exhibit 7-7 of the Seneca II Permit Application Package). Review of Table 21 (Appendix A) <br />shows Spring #t to historically exhibit a [aMg-HCO3SO4 type water with a relatively Low <br />TDS value; however, na flow was observed at this site in the falls of 1987 through 7990. <br />During 7990, Spring #2 exhibited a CaMg-504 HC03 type eater and a slight increase in TDS. <br />Due to their location, it is unlikely that either spring is impacted by mining. The last <br />time that tlow in the fall was noted at Spring #3 was in 1984. <br />Spring #5. This spring is located in the Cow Lamp Creek drainage but, due to its <br />location, is unlikely to be disturbed by mining. No flow was observed at this site in the <br />falls of 7987 through 1990. A 1985 analysis shows this water to be a Mg-S04 type with an <br />extremely high TDS value of 14,200 mg/l. This high TDS value can be attributed to <br />78 <br /> <br /> <br />J <br />