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• presented on Table 16. Anew maximum historic flow (95 cfs) was estimated for Site 29. Flow magnitudes in <br />general were noted to be markedly higher than those experienced during 1995. <br />1996 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 fall <br />and winter. Currently however, and since approximately 1985, Sites 900 and 29 have typically flowed year- <br />round due to the discharge influences of other mines upstream of the gaging stations. Site 700 also now typically <br />flows year-round due to discharges associated with upstream mining operations. As shown in Figures 15 <br />through 20, spring runoff continues to comprise most of the annual flow. Tables l OB, 12B, and 13B provide <br />period of record statistical summary information for water levels at surface water monitoring sites 900, 700, and <br />29. <br />Water Quality -Water quality monitoring data for the Mine 3 surface water monitoring stations is presented on <br />Tables 10, IOA, 12, 12A, l3, and 13A. Per the approved hydrology monitoring program, water quality samples <br />were collected at all three surface water monitoring sites during the 1996 Water Year. Plots of historic water <br />quality data for Foidel and Middle Creek sites arc presented as Figures 21 through 25. Total dissolved solids <br />concentration data for the period of record at site 29 is presented as Figure 21. Period of record field <br />conductivity data for sites 700, 29, and 900 is presented as Figures 22, 23, and 24 respectively. 1995 Water <br />• Year field conductivity data is plotted collectively for all three sites and presented as Figure 25. <br />The historic base level field conductivity on Foidel Creek (Site 900, Figure 24) measured during spring runoff, <br />averaged approximately 1000 umhos/cm. Since 1981 the typical level has steadily increased although this trend <br />appears to have leveled somewhat in 1996 with values ranging between approximately 1800 and 3000 <br />umhos/cm, slightly lower than 1995. The overall increasing general trend is likely attributable to the effects of <br />other mine discharges upstream of Mine No. 3. The imgation season field conductivity levels at Site 900 <br />exceeded 3000 umhos/cm during periods in August and September of 1996. A similar trend is apparent at Site <br />29 (Figure 23) although relatively lower Held conductivity values were again apparent for the 1996 Water Year <br />as compared to 1993 and 1994. Period of record field conductivity data for Site 700 (see Figure 22) also <br />exhibited levels comparable to recent years with no obvious trend evident. Field conductivity values at this site <br />are typically lower than those encountered at Sites 29 and 900. <br />Most monitored water quality parameters for surface water sites 700, and 29 were observed to fall within <br />previously established ranges for the 1996 Water Year with the exception of a new maximum nitrite value <br />recorded for site 700 during April, and a new minimum lab conductivity value recorded for site 29 in April. At <br />site 900, new minimum conductivity and TDS values were established in April while new maximums for <br />hardness, dissolved magnesium, and TDS occurred in September. <br />~J <br />-6- <br />