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Permit Number C-1994-082 Page 14 of 17 <br />14 are not included in the SL-6 Phase III portion of the bond release application. Sample data were <br />collected and reviewed for all required parameters. Sample data have been reported on a quarterly <br />basis in discharge monitoring reports filed with the CDPHE and the CDRMS. These DMRs indicate <br />that no exceedances of permit limits have occurred in the past three water years. <br /> <br />Clean Water Act Effluent Limitations (40 CFR Part 434) <br /> <br />Monitoring data for the past three years indicate that the Yoast Mine has not caused exceedances of <br />either limitation identified in 40 CFR Part 434 applicable to reclamation areas on coal mines <br />(settleable solids of 0.5 ml/l and pH of 6.0 to 9.0). Yoast Mine only notes settleable solids values that <br />are at or above the detection limit of 0.4 ml/l; no exceedances of 0.4 ml/l were noted. <br /> <br />Impacts to Alluvial Valley Floors (AVFs) <br /> <br />The Division determined that there are no potential AVFs in the Grassy Creek watershed and two <br />potential AVFs in the Sage Creek watershed. The AVFs within the Sage Creek watershed include <br />two small fields located in the upper reaches of Sage Creek near the failed Sage Creek Reservoir site <br />and approximately 86 acres of flood irrigated alfalfa hay along Sage Creek in Section 30. <br /> <br />Sage Creek Reservoir Site <br /> <br />Two fields located just upstream from the former Sage Creek Reservoir dam (Sections 13 and 18) are <br />identified in the Yoast application as sub-irrigated native wetlands and sub-irrigated grass hay fields. <br />The native wetland area is the area once covered by the Sage Creek Reservoir, which failed in 1985. <br />This area is currently used for grazing. The area immediately upstream from the former reservoir site <br />is currently used as a grass hay field. <br /> <br />These fields are located in the upper reaches of Sage Creek, and therefore are not typical of alluvial <br />valley floors in this area with agricultural potential. However, the upper field (approximately 10 <br />acres) is currently being farmed for hay, and the second field has the potential to be put to use as a <br />sub-irrigated hay field. Furthermore, during a site visit on May 19, 1995, the upper grass hay field <br />was being flood irrigated by means of an irrigation ditch along the eastern edge of the field. Due to <br />the existence of flood irrigation and the presence of sub-irrigation of the unconsolidated stream laid <br />deposits in the fields immediately upstream from the past Sage Creek Reservoir, these fields are <br />determined to be alluvial valley floors. <br /> <br />The field just above the breached Sage Creek dam is dissected by the streambed. This area is <br />undeveloped rangeland that is currently used for grazing. The limited size of the field would make it <br />difficult for farm equipment to operate. This field is not typical of agriculturally productive alluvial <br />valley floors in this region. <br /> <br />Land management information and farm productivity values for the hayfield in Section 18 are <br />provided in Exhibit 16-3 of the PAP. The field in Section 18 is the smallest of three fields managed <br />as part of a limited sheep ranching operation. Dominant grass species in the field are Smooth Brome <br />and bluegrass. The field produces one hay cutting per year at a maximum rate of 2 tons/acre for a <br />maximum production of 20 tons/year. The maximum annual production from the total ranching