2012-01-06_PERMIT FILE - C1982057 (24)

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Stream Buffer Zones • As defined in Section 4.05.18 of the Colorado Surface Coal Mining Reclamation Act, the mining operation shall not disturb the stream buffer zone within 100 feet of a perennial stream or stream with a biological community. None of the streams of the Seneca II-W complex are categorized as perennial, although during wet years some streams may flow year round. The streams are intermittent; however, the baseline hydrology monitoring program has not been sufficient to determine whether biological communities as defined by Section 4.05.18(3) are present. Thus, mining and reclamation activities in the vicinity of Dry Creek are designed to comply with the stream buffer criteria. Two haul roads and one topsoil stockpile have been constructed within the 100-foot stream buffer zone along Dry Creek. The Seneca II-W Mine Entrance Haul Road (MEHR) crosses Dry Creek just downstream of the confluence of Hubberson Gulch and Watering Trough Gulch (see Exhibit 13-12.1, Tab 13). Haul Road G (HRG) and Topsoil Stockpile RR (TSRR) are located approximately one mile downstream of the MEHR, and HRG also crosses Dry Creek at this location (see Exhibit 13-19.1A). Disturbances to the stream buffer zone in the vicinity of the MEHR are limited to the placement of a 60-inch culvert in Dry Creek, the MEHR, and a small overland flow conveyance ditch approximately 550 feet in length that conveys water along the north side of the MEHR (see Exhibit 13-12.1)• The ditch is designed to adequately convey runoff from the MEHR without contributing additional suspended solids to streamflow along Dry Creek. Because of the low gradient of this ditch (0.8 percent), no energy dissipation was needed at the ditch outlet point. Stream buffer zone signs have been placed along the northern and southern edges of the MEHR within the permit boundary to identify the stream buffer zone at this location. • 7 Revision 9/98