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SECTION 2.0 Annual Hydrology Report for Trapper Mine (2002) 2.1 Climatological Data The 2002 National Weather Service Cooperative monthly summaries and the historical precipitation summary (1978-2002) are included in Section 2.5. 2002 precipitation totaling 11.19", provided 83 percent of the established historical pre-mining (44-YR) annual precipitation mean but only 68 percent of the project-to-date annual precipitation mean (Figure 2-1). The highest monthly precipitation amount was recorded in August (1.96") with the second and third highest totals occurring in September and October (1.57" and 1.34" respectively). Precipitation amounts were well below normal for the months of January, February, May, June, July and December. For the third year in a row, the temporal distribution of precipitation resulted in a much drier than usual growing season. 2.2 Pit Dewatering and Consumptive Water Use for 2002 During 2002, Trapper dewatered approximately 17 acre-feet of water from two active pits and 3.3 acre- feet of water from a G-Pit dewatering well. (Table 1-1 of Section 2.5 shows the pumping volumes for each activity). No new dewatering wells were established in 2002. All pit water was routed into the NPDES drainage system with resulting discharges monitored accordingly. Pit dewatering volumes were markedly lower in 2002 as compared to 2001 partly owing to a lighter snowpack runoff occurring in the spring. Approximately 80 acre-feet of water were used for dust suppression on haul roads and topsoil handling operations in 2002. This is only 4% lower than the 2001 total. As previously noted, May, June and July of 2002 were drier than usual, however during August, September and October higher than average precipitation was received which could have contributed to the 4% decline in dust suppression water. Dust suppression water demands continue to be somewhat offset by the successful application of dust suppression chemical treatments on haulroads. Haul routes were similar in 2002 as 2001. Total water volume used by Trapper Mine in 2002 was approximately 100 acre-feet, slightly lower than the 2001 total. 2.3 Mining Advancement and Ash Disposal Sites The 2002 Annual Hydrology Report maps depict the following mining activities through year-end: a) Project to date utility waste disposal sites. b) Project to date pit advancement (toe of pit). c) Project to date monitoring wells, and natural and spoil springs and seeps. In the 2002 report, all spring and seep sites within the permit area are depicted to provide location information for future reference. Sites that exhibited Flows exceeding 5 gpm during the reporting year are distinguished from sites exhibiting flows less than 5 gpm. Three maps (Annual Hydrologic Report Map 2, Sheets 1, 2, & 3) are provided to present this information. These maps include the locations of monitoring wells that are proximal to active mining and that could be affected in this permit term. 2.4 Monitoring Points Rather than submitting an additional map series, please refer to current Permit No. C-81-010, Map M52, for locations of all the operational hydrologic monitoring points. No new ground water monitoring wells were installed during 2002. No additional NPDES discharge points were constructed during 2002 No new pit dewatering wells were installed during 2002. . Monitoring well GP-1 will be mined through in 2003.