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-23- <br />IX. Probable Hydrologic Consequences and Cumulative Impacts Assessment - <br />RuZes 2.05.6(3) and 2.07.6(2)(c) <br />The Munger Canyon operation will potentially affect surface water and ground <br />water. Cumulative impacts to the hydrologically adjacent area would result <br />from the Munger Canyon operation impacts combined with the hydrologic impacts <br />produced by other operations (namely the Dorchester Fruita Mines and the <br />McCZane Canyon Mine) within the same hydrologic system(s). An assessment of <br />these impacts is presented here. <br />Probable Hydrologic Consequences <br />The anticipated impacts of the Munger Canyon operation on the quality and quantity <br />of ground water and surface water in the area are minimal. This is due mainly <br />to the small area of surface disturbance related to the mine, as well as the <br />characteristics of the ground water environment. <br />The disturbance related to the operation will encompass approximately 35 acres <br />in Munger Canyon. Compared to the total drainage area in Munger Canyon (5085 <br />acres), approximately seven-tenths of a percent of the Munger Canyon drainage <br />will be impacted by the operation. Although increases in concentrations of <br />total dissolved solids (TDS) and total suspended solids (TSS) are expected to <br />result fmm the disturbance, the areal comparison indicates that the significance <br />of the increases in TOS would be diminished due to dilution, and TSS will be <br />controlled by sediment ponds. Furthermore, once the runoff from the Munger <br />watershed reaches the East Salt Creek Valley, the impact would be diminished <br />further. The disturbance due to the operation only accounts for five- <br />hundredths of a percent of the total drainage area of East Salt Creek above <br />the confluence with Munger Canyon (67,228 acres). <br />There is a potential for the operation to deplete the quantity of flow in Munger <br />Creek. This potential is slight. Water stored in impoundments will always be <br />less than two acre-feet per structure and there are only two structures. The <br />ponds will also be dewatered to the required storage capacity following any major <br />storm event. Additionally, precipitation in the area is so low (8.8 inches <br />annually) that it is expected that very little to no water will be stored in <br />either impoundment most of the time. <br />Very little ground water was encountered during exploratory drilling in and <br />around the permit area. Salt Creek Mining Company does not expect to have to <br />discharge mine water as a result of consistent inflow into the mine. Some <br />depletion of surface water by infiltration into the mine workings through natural <br />and mine-induced fractures may occur. The amount of depletion would be minor <br />due to the steep local topography and low precipitation. The slope varies from <br />2v:lh to 6v:Ih, and the precipitation is 8.8 inches per year. <br />The very low amount of surface water runoff that does occur is concentrated in <br />periods of snowmelt and thunderstorm events. These events produce short duration, <br />high volume runoffs which, when coupled with the steep topography, greatly <br />favors surface water runoff over the infiltration of water. <br />