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<br />• Runoff from approximately 6 acres of disturbed land and 14 acres of undis- <br />turbed land in dryland wheat production is routed through a sedimentation <br />pond in the northeast portion of the permit area. Peabody Coal Company <br />received a water right for this pond on February 9, 1982 (see Appendix G- <br />I). Outflow from the sedimentation pond is monitored at NPDES Discharge <br />Point 001 (Permit No. CO-0037656). Table G-2 presents the results of <br />weekly monitoring at the NPDES discharge point. A copy of the NPDES <br />permit granted to Peabody Coal Company is included in Exhibit N. Compari- <br />son of the NPDES effluent limitations with the data presented in Table G2 <br />indicates that the pH, floating solids/visible foam, and oil and grease limita- <br />tions and monitoring frequency requirements have been consistently met. <br />There have been several excursions beyond the 25 mg/I total suspended solids <br />limitation. These excursions have been caused by algal blooms which are <br />enhanced by nutrient rich runoff from the 14 acres of cultivated land. <br />Peabody Coal Company has attempted on several occasions to rectify This <br />problem through application of copper sulfate algalcide. The problem con- <br />times to persist, so Peabody Coal Company has applied for a variance from <br />• the total suspended solids limitation. A copy of the request for variance <br />submitted to the Colorado Water Quality Control Division is included in <br />Appendix G-2. At this time (February 1982), no action has been taken by the <br />Colorado Water Quality Control Division <br />Mesa Gravel will enlarge the sedimentation pond in the summer or fall of <br />1982 to accommodate the runoff from the expanded operations which this <br />permit application addresses. The design specifications for this enlarged <br />sedimentation pond are detailed below. The enlarged pond will have a stor- <br />age capacity of 1.20 acre-feet which is 2 times as large as the existing pond <br />(0.56 acre-feet). It is anticipated That the enlarged storage capacity will <br />provide holding times sufficient for organic matter resulting from algal <br />blooms to settle out before water is released. A manually activated de- <br />watering device will also be utilized to help assure adequate water quality. <br />Peabody Coal Company will apply for a water right to the additional .64 <br />acre-feet storage capacity of This pond over the existing pond's storage <br />capacity. <br />• <br />G-3 <br />