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Clean Water Act Effluent Limitations (40 CFR Part 434) <br />Monitoring data for the past five years indicate that the PSCM has not caused exceedances of either <br />limitation identified in 40 CFR Part 434 that is applicable to reclamation areas on coal mines <br />(settleable solids of 0.5 ml /1 and pH of 6.0 to 9.0). Peabody Sage Creek Mine only notes settleable <br />solids values that are at or above the detection limit of 0.4 ml /1; no exceedances of 0.4 ml/l were <br />noted. <br />Impacts to Alluvial Valley Floors (AVFs) <br />An AVF is present in the Fish Creek basin downstream of Pond 004. This AVF was originally <br />discussed on page 7-279, Tab 7 of the Seneca II Mine permit and the discussion was inserted into the <br />Peabody Sage Creek Mine permit. There is a 63 -acre parcel where irrigation was practiced on this <br />AVF from the point where Cow Camp Creek is confluent with Fish Creek to the confluence of Fish <br />Creek and Trout Creek. However, the irrigation ditch for this parcel washed out in 1997 and has not <br />been used since. An impact projection analysis, conducted by the Seneca II Mine as noted in Tab 7, <br />Section VILA. Lc in C-1980-005 and included in the Peabody Sage Creek Mine permit, concluded <br />that total dissolved solids (TDS) increase in the Fish Creek stream flow as a result of surface water <br />discharges from NPDES4 on the order of 76 mg /1 and 74 mg /1 for the months of June and July <br />respectively. The projection equates to TDS concentrations in the Fish Creek streamflow ranging <br />from 497 to 607 mg /1. <br />June and July TDS values at Site SSFI I (upper Fish Creek) and Site SSF13 (lower Fish Creek) from <br />2003 to 2015. The maximum increase of TDS between the sites in June was 50 mg/ I (average = 25 <br />mg/1) compared to a predicted 76 mg/ 1 increase. The maximum increase of TDS between the sites <br />in July was 70 mg/1(average = 21) compared to a predicted 74 mg/ 1 increase. The predicted TDS <br />values in June and July of 497 and 607 mg/1 were occasionally exceeded at Site SSF13 (680 mg/ 1, <br />2,000 mg/1 is the crop tolerance level). <br />Protection of the Hydrologic Balance <br />According to Rule 3.03.2(2), the Division must conduct an inspection and an evaluation to determine <br />whether pollution of surface or subsurface water is occurring, the probability of future occurrence of <br />such pollution, and the estimated cost of abating such pollution. <br />Based on the review of the water monitoring data for the SL -4 bond release area of the Peabody Sage <br />Creek Mine, the observed hydrological impacts are consistent with those predicted in the probable <br />hydrologic consequences (PHC) section of the DRMS permit (C-2009-087). <br />Water pollution is not occurring from the SL -4 bond release area of the Peabody Sage Creek Mine <br />and, based on a review of the monitoring data and on -the -ground observations, there is no potential <br />for future water pollution from the bond release area. Water quality at the alluvial Ground Water <br />Point of Compliance well is within the prescribed limits. Based on the foregoing observations <br />regarding hydrologic impacts, the Division finds PSCM has minimized disturbance of the hydrologic <br />balance in the bond release area and adjacent areas, and prevented material damage outside the <br />permit area. <br />C-2009-087 Page 12 of 14 <br />