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Meteorological Station located approximately seven miles southwest of the Seneca II Mine. <br />• Climatic conditions are similar between Che two mines. <br />Data from the National Climatic Data Center for the Hayden Station was used to evaluate <br />the precipitation trend. For this year, 18.74 inches of precipitation was measured, which <br />was 1.90 inches (114) greater than the 1961-1990 average. All months but November, <br />December, March, and Sep [amber were above average. Snowpack zvnoff, as estimated by <br />totaling November through April precipitation values, was 8.51 inches, which was 0,10 <br />inches 118) above the 1961-1990 average. <br />The Seneca II precipitation gage measured 18.81 inches this year. This value is 0.61 <br />inches 1381 less than the 1981-1999 average. <br />Ground Water <br />Water Levels. water level data are presented in Appendix B. Water level reports for data <br />collected since 1990 ate presented immediately after the water level hydrograph of all <br />• historic data for each respective well in the same appendix. By presenting all historic <br />data, trends related to seasonal and annual variability and poee ible mining related <br />impacts are more clearly evident. Table 3 (Summary of Ground Water Monitoring Wells) is <br />presented as a reference fox the reader. No wells were drilled or abandoned thin year. <br />Water level measurements obtained in non-flowing wells are taken with water level <br />indicator, or in the case of a few shallow alluvial walla, directly from a steel tape. <br />Pressure readings lin psi) obtained from flowing wells with pressure gages are multiplied <br />by 2.31 to obtain head 3n feat. Fos the sake of brevity, the prefix that precedes all <br />well names will be dropped throughout this report (except in the case of nested walla with <br />a similar number). As an example, Well SCAL46 will be referred to as well 46. <br />- Alluvium. The alluvial monitoring wells are located along Cow Camp (Wells 46 antl 69), <br />Sond (Well 6B), Grassy (Wells 33, 34, 70, and 71), and Little Grassy Creeks (Wells 6, 31, <br />31A, and 32). These wells exhibit seasonal fluctuations in water levels. The spring <br />runoff-infiltration stimulates a water level rise, and as the drier fall season <br />approaches, water levels decline. Generally, water levels at most alluvial wells fell <br />within their historic ranges. However, Well 70 (located on lower Grassy Creek), continues <br />• to exhibit a decreasing water level [rend. Water levels here, as well ae with most <br />3 <br />