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C• Tables 7 through 12 tabulate the percentage of milliequivalents per liter of major ions and total dissolved solids (TDS) for each well sampled in 1986. Historical data is provided for comparison purposes. It is important to noto here that percent anions for 1981 and 1982 are not tabulated since the program that generates these tables cannot use the format in which this old data exists. In addition to a discussion of general water types, any parameter which exceeds potentially applicable water quality criteria will be discussed. This criteria list is found on Table 13. 1. Alluvium Well CW-532, located further upstream on Little Grassy Creek, displays a sodium sulfate type water. Although water type has not changed, TDS at this well has increased since 1981. This is due to mining upgradient of here. Progressing down valley, the alluvium picks up spoils water discharge exemplified by calcium replacing sodium as the major cation at well GW-56-A. TDS increases as one progresses downstream, in addition to progressing with time. Well GW-531-A2 is downstream of the discharge of the Wedge Impoundment. It is also a calcium sulfate type water. TDS fluctuates up and down from year to year, implying that the baseflon TDS has stabilized and that changes are due to ~. annual changes in precipitation. Manganese concentrations at all three wel}s, especially in the fall, exceed the irrigation standard of 0.2 mg/1. This appears to be of little significance because there is no irrigation being employed {n the Little Cressy Creek basin. The one well completed in the Grassy Creek alluvium, GW^533, has a calcium sulfate type water. TDS has remained relatively stable here, and is less than concentrations observed upstream on Little Grassy Creek due to dilution by undisturbed upper Cressy Creek alluvial water. Manganese here also exceeds irrigation standards; however, no irrigation is currently in practice in this basin. In the Fish Creek tributary (Cow Camp Creek) alluvium, water quality is measured at one well, CW-546. Its water quality is notably different from other alluvial water in the Seneca Mine area. This well exhibited a high TDS concentration prior to mining in the vicinity (2,068 mg/1 in November 1982). In 1986, its average TDS had increased to 2,677 mgll. Th{s is considerably higher than the 2,130 mg/1 average TDS observed immediately upstream at the 004 pond discharge. Natural spring d5 is located upstream of the 004 pond ~,'\•. in the same alluvium and is most likely undisturbed by mining. Although ~i is floe is low, it has a very high TDS of 14,200 mg/1 and is also a magnesium sulfate type water. 18