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Page 5, June 13, 2007 <br />Rule 4.05.3(7)(c) Energy dissipators shall be installed when necessary at discharge points, <br />where diversions intersect with natural streams and exit velocity of the diversion, flow is greater <br />than that of the receiving stream. <br />The application is in compliance with this rule. The previously approved free-fall outlet of a <br />section of the culvert onto rock riprap below provides for dissipation of energy prior to discharge <br />through an additional section of culvert that discharges to the river. <br />Rule 4.05.4 See the Rules for the text of this rule. <br />Rule 4.05.3 above was applied to this project. <br />Rule 4.05.7 Discharge from sedimentation ponds, other treatment facilities, permanent and <br />temporary impoundments, coal processing waste dams and embankments, and diversions shall <br />be controlled by energy dissipators, riprap channels and other means or devices, where <br />necessary, to reduce erosion, to prevent deepening or enlargement of stream channels, and to <br />minimize disturbance of the hydrologic balance. Discharge structures shall be designed <br />according to standard engineering design procedures. <br />The application is in compliance with this rule. The subject structure is a diversion that includes <br />a catch basin (energy dissipater)and culverts that control the discharge. The structure reduces <br />erosion, prevents deepening or enlargement of the drainage way, and minimizes disturbance to <br />the hydrologic balance. The structure is designed according to standazd engineering design <br />procedures, and beazs the certification of a registered engineer. <br />Rule 4.05.18(1) No land within 100 feet, or greater distance if required by the Division, of a <br />perennial stream, an intermittent stream, or an ephemeral stream with a drainage area greater <br />than one square mile, shall be disturbed by surface and underground coal mining operations <br />unless the Division specifically authorizes surface or underground mining operations closer to, <br />or through such a stream upon finding: <br />Approval of this technical revision specifically authorizes mining operations closer than 100 feet <br />of the North Fork of the Gunnison River. Findings include: <br />Rule 4.05.18(1)(a) That surface coal mining operations will not cause or contribute to the <br />violation of applicable water quality standards; <br />The application contains no best management practices to minimize the deposition of materials <br />eroded from the site during construction. Recommend the application be amended to describe <br />those best management practices for construction sediment control (sediment logs, silt <br />fencing, and immediate seeding and mulching of disturbed areas). <br />