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-lo- <br />V. Hydrologic Balance (con't) <br />The results of the overburden analysis indicate a slight potential for the <br />introduction of additional constituents into the surface water system cahich <br />could result in degradation of water quality. Overburden would be placed in <br />a controlled manner at the excess spoil pile and within the backfilled pit. <br />Topsoil will be spread on the overburden and these areas will be vegetated <br />and thereby stabilized. These overburden materials would not be exposed to <br />surface flow under these conditions. If the materials were somehow exposed <br />during the life of the mine, through surface erosion or percolation, and if <br />contaminants were introduced into the surface water, the runoff would still <br />be totally contained within the sediment control system. Should some <br />failure of this system occur an increa the concentration of contaminants <br />will be detected y the water quality monitoring program that is presented <br />in a app is <br />The mine will not advance into the Dowden Gulch catershed during this permit <br />term. Monitoring of surface water in Dowden Gulch will commence one year <br />prior to mining to determine baseline conditions so that a determination of <br />the effects of mining on the hydrology of Dowden Gulch can be assessed. <br />The northeastern portion of the permit area is within the upper reaches of <br />the Dry Creek watershed. The only disturbance related to the mining operation <br />which is in this drainage is the permanent overburden pile. Runoff generated <br />from the pile will be diverted into the Hayden Gulch drainage and routed <br />through the sediment control system. The amount of area removed from the <br />Dry Creek watershed as a result of the diversion is insignificant; it is <br />approximately .002% of the total catershed. <br />The area affected by the loadout in Dry Creek is insignificant with respect <br />to the Dry Creek drainage; approximately .0006% of the total watershed. <br />Runoff from the area will be contained by a system of ditches, culverts <br />and sediment ponds. Any water contained within the system will be required <br />to meet applicable effluent standards upon discharge. Surface water will be <br />monitored for quantity and quality downstream on Dry Creek as stipulated <br />in this document. <br />The potential for detrimental affects of the mine on local surface water <br />quality is minimal. This determination has been made by the Division on the <br />basis of information provided by the applicant. However, it is standard <br />procedure for the Division to require monitoring of surface water upstream <br />(unaffected) and downstream (potentially affected) of the disturbance to <br />provide further documentation of this conclusion. H-G Coal Company has <br />agreed to the continuation of the surface water monitoring program and <br />will monitor all parameters required by the Division. Details of the monitoring <br />program are presented in Section 2.05.6 of Volume I of the application. <br />loo major areas of concern were raised during the sediment control review. <br />These were: 1) Sediment yields that were questionably calculated using <br />the Universal Soil Loss Equation, and 2) Inadequate culvert sizing. <br />