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• Flows - Streamflow measurements are gauged at the two USGS sites and at Site 29. Due to the size of the <br />streams at the established monitoring locations, flows are rated rather than measured using a more accurate <br />controlled section such as a flume. The USGS maintains continuous recorders at Sites 700 and 900 and <br />provides data summaries to CYCC. Plots of historic maximum and mean flow measurements on Foidel <br />Creek at Site 900 are presented as Figures 15 and 16 in this report. The 1995 Water Year runoff <br />hydrograph for site 900 is presented as Figure 17. Plots of historic maximum and mean flow measurements <br />on Middle Creek at Site 700 are presented as Figures I8 and 19. The 1995 Water Year runoff hydrograph <br />for site 700 is presented as Figure 20. Mean historic monthly flows for Site 29 are presented as Figure 21; <br />Flow data for the 1995 Water Year as Figure 22. Selected flow rate data consisting of historical and 1995 <br />Water Year maximum and minimum recorded flows, and 1995 irrigation season (June through September) <br />mean flows for Sites 900,700, and 29 are presented on Table 16. No new maximum or minimum flows <br />were established during the 1995 Water Year. Flow magnitudes in general were noted to be higher than <br />those experienced during 1994. <br />1995 Water Year data for these sites shows typical seasonal variation with rapid rise and fall of flow rates <br />associated with spring runoff. Historically these three surface water sites often stopped flowing during the <br />fall and winter. Currently however, and since approximately 1985, Sites 900 and 29 have typically flowed <br />year-round due to the discharge influences of other mines upstream of the gaging stations. As shown in <br />Figures 15 through 22, spring runoff continues to comprise most of the annual flow. <br />• Water Quality -Water quality monitoring data for the Mine 3 surface water monitoring stations is presented <br />on Tables 10, 1(}a, 12, 12a, 13, and 13a. Per the approved hydrology monitoring program, water quality <br />samples were collected at all three surface water monitoring sites during the 1995 Water Year. Plots of <br />historic water quality data for Foidel and Middle Creek sites are presented as Figures 23 through 27 and <br />Figure 30. Total dissolved solids concentration data for the period of record at site 29 is presented as Figure <br />23. Period of record field conductivity data for sites 700, 29, and 900 is presented as Figures 24, 25, and <br />26 respectively. 1995 Water Year field conductivity data is plotted collectively for all three sites and <br />presented as Figure 27. <br />The historic base level field conductivity on Foidel Creek (Site 900, Figure 26) measured during spring <br />runoff, averages approximately 1000 umhos/cm. Since 1981 the typical level has steadily increased although <br />this trend appears to stabilize somewhat with 1995 values ranging between approximately 2000 and 3200 <br />umhos/cm, slightly lower than last year. This increasing general Vend is attributable to the effects of other <br />mine discharges upstream of Mine No. 3. The irrigation season field conductivity levels at Site 900 again <br />exceeded 3000 umhos/cm during August and September of 1995. A similar trend is apparent at Site 29 <br />(Figure 25) although markedly lower field conductivity values are apparent for the 1995 Water Year. Period <br />of record field conductivity data for Site 700 (see Figure 24) also exhibits low levels for the year. Field <br />conductivity values at this site are markedly lower than those encountered at Sites 29 and 900. <br />• <br />All other monitored water quality parameters for surface water sites 700, 900, and 29 are observed to fall <br />-5- <br />