2004-12-06_REVISION - M1977472 - Laserfiche WebLink

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BLM East Gravel Pi[ Exhibit G Water Information WATER QUALITY, SURFACE & GROUND The gravel pit is located along the divide between the Michigan River and the Canadian River subwatersheds, both tributary to the North Platte River. The streams' classified uses are Class 1 Coldwater aquatic life, Class 1 recreation, water supply, and agricultural, except the Michigan River, which is Class 2 recreation. There are no designated use impairment stream segments in the North Platte River watershed, and the project area is considered to be meeting Standard #5. Maintaining the "eggshell" border throughout the duration of the mining operation will result in minimal surface runoff. [f any runoff did leave the north half of the site, it would likely travel to Ballinger Draw (west-northwest) or Suddeth Draw (east-northeast). These ephemeral draws have livestock impoundment's within a mile of the pit that would retain any surface runoff [hat [raveled that far. Runoff from [he access road and any of the southern half of the pit (if any) would be captured by an abandoned irrigation ditch that is adjacent to the site. It is unlikely that any other surface water would be impacted by the pit development. If pit development were to result in runoff pathways, then erosion control measures would be implemented to control runoff and eliminate accelerated erosion. Direct impacts from closing the pi[ would be the same until successful revegetation occurs, after which more surface water runoff would remain in the immediate location of the pi[. HYDROLOGY AND WATER RIGHTS: Ground water uses within a mile of the mine include the Road Gulch Spring, Box Spring, Victor Spring, and Dry Fork Spring. BLM holds [he water rights on all of these drainages. It is likely that the mine location is a ground water rechazge zone, with precipitation infiltrating through the gravel and then traveling along the Coalmont Formation. Any recharge from the mesa would be expected to travel away from Box and Victor Springs as the Coalmont Formation in the area is dipping to the south/southwest. Some of Road Gulch's and Dry Fork's recharge, however, would come from the mesa. The proposed mining plan would leave the perimeter of the mesa top gravel unmined, and a portion of the recharge zone would be maintained in its existing condition. Prior to respreading the topsoil, a gravel "lens" of at least 12 inches shall be spread on the disturbed site. The smaller lens won't have the storage capacity of the pre-mined gravels, but precipitation will still be able to infiltrate the gravels and travel down the dip as before. There are no other known waters or water rights that would be impacted by this proposed mining operation.