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• -7 DIVERSION DITCHES The Northwest Diversion ditch will collect runoff from undisturbed areas and divert it around the disturbed area to Grassy Creek This ditch is a temporary structure and is designed to handle a 10-year runoff event. Riprap will be used in the steeper reaches of the ditch. Numerous collection ditches route overland flow from disturbed areas to sediment ponds for treatment. These ditches have been and are planned to be constructed along the several haul roads throughout the permit area. The Grassy Creek Diversion is located in the northwest corner of the mine. This diversion re-routes Grassy Creek to the West of the Northwest Impoundment to avoid mixing waters from disturbed and undisturbed areas. Grassy Creek is a temporary stream channel diversion and has been designed for a 10-year, 29-hour precipitation event, with a resultant peak discharge of 298 cfs. This channel will carry the run- off from this event with a velocity of 7.8 fps. Since the Grassy Creek Diversion ditch is a grass-lined channel, Seneca Coals Ltd. will monitor and maintain the channel when peak discharges are approached. P1ONITORING Currently, Seneca Coals operates 6 stream gauging stations and 2 NPDES discharge points. Stream gauging stations are located upstream and downstream From the mine area, along ephemeral and intermittent stretches of Little Grassy Creek, Grassy Creek, and Fish Creek. These sites are sampled monthly for pH, conductivity, temperature and flow; and quarterly for all other parameters required by the Division. NPDES discharge points are sampled weekly for the NPDES permit-specified para- meters and also quarterly for the parameters required by the Division. The dis- charge from the South Section 12 pond will be monitored as a 3rd NPDES discharge point once it is operational. The monitoring system proposed by Seneca Coals is adequate to measure accurately water quality and quantity of the discharge from the permit area and to detect and assess any impacts from mining to the hydrologic balance. WATER RIGHTS There are ten adjudicated'surface water rights within the adjacent area of the Seneca II mine. Nine of these are registered to the Seneca ZI mine (including 289.6 acre feet from Grassy Creek for the Wedge impoundment). The remaining surface water right is Cook Ditch, which can obtain 2.54 acre feet from Grassy Creek. Cook Ditch is recorded to be located upstream from mining in the NE'aSWa of Section 34, Township 6 North, Range 87 West. The right was adjudicated in 1909 for irrigation. Field inspection of the area indicates that the ditch is not currently in existence and does not appear to have ever existed. The surface water hydrology section is in compliance with Rules 2.04.7, 2.05.3(4), 2.05.6(3) and 4.05.