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State Reg. <br />hydrograph for site NPDES 004 as shown on Figure 7-31. The . <br />hydrograph was constructed by plotting mean monthly flow <br />against acres disturbed within the mining area. As is evident, <br />flo~N increased shortly after mining began. Base flaw in August <br />and September peaked in 1984 at 0.138 cfs; base flow has since <br />declined, stabilizing at approximately 0.12 cfs. There is no <br />evidence to indicate that flow from the mine area will increase <br />in the future especially in light of the fact that <br />approximately 80 percent of the mine area which lies within the <br />NPDES 004 drainage area has already been disturbed. <br />The increase in flow from the mine area as monitored at NPDES <br />004 is primarily expressed by the discharge from Spoils Spring <br />#1 located immediately above the north edge of the 004 pond. <br />Flo~,v from this spoil spring began during the winter/spring of <br />1984/1985 during which time a furthest downslope lr'adge pit was <br />being filled in. Flow monitoring began in the summer of 1985 <br />with measurements in July and November. Upon request form the • <br />MLRD, frequency of monitoring Spoils Spring lil was increased to <br />biweekly during the summer of 1986. The flow data from this <br />site, summarized in Table 7-61 and plotted on Figure 7-31, <br />indicate that flow increased from 0.085 cfs in November 1985 to <br />0.169 cfs in June 1986. However, flow has since receded back <br />to a base flow level of approximately 0.08 cfs during August <br />and September 1986, roughly the same flow measured during July <br />and November 1985. From these spoil spring data coupled with <br />the flow data for NPDES 004, there is no indication that base <br />flow discharge from the mining area will increase in the <br />future. Future flow monitoring of both of these sites will <br />likely substantiate this assumption. <br />Monitoring of flow at site SW-S2-9 in the undisturbed Bond <br />Creek drainage began in the spring of 1986. The limited data <br />collected to date showed a peak flow of 0.854 cfs in April and <br />a low flow of 0.014 cfs in July. It is likely that no flow • <br />conditions will prevail during the base flow months of August <br />and September. Future monitoring data will be reported and <br />discussed in annual hydrology reports. <br />7-205 Revised 10/01/86 <br />