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i , <br />5 <br />V. Hydrologic Balance: Surface Water - Rules 2.04.5, 2.04.7, 2.05. <br />n nc ~ __~ w nr <br />Information on surface water can be found in the permit application in <br />Sections 3.3.7, 4.2.3, 4.2.3, 4.5.3 and 5.1 of Volume I. The information <br />contained in these sections is not sufficient for the Division to predict <br />worst case scenarios for mining related impacts on surface water conditions of <br />the permit, adjacent and general areas of the mine. The following issues must <br />be addressed by the applicant to the satisfaction of the Division before a <br />finding of compliance with this section can be made. <br />1) Figure 4.2-5 of the permit application shows the five year extent <br />of underground mining extending into the South Canyon Creek drainage. <br />The applicant must describe the anticipated impacts of mining to the <br />hydrologic balance of South Canyon Creek. A surface water monitoring <br />plan for South Canyon Creek also must be submitted by the applicant. <br />2) The applicant must submit flow regime data for the Colorado River <br />sufficient to identify critical low flow and to identify seasonal <br />variations in flow and chemistry. Specifically, flow data must be <br />submitted in connection with the monthly field measurements of <br />chemistry submitted in the application. <br />The following are the findings of compliance which the Division can make at <br />this time: <br />Diversions - Temporary <br />The temporary diversion, Channel A, which drains the undisturbed area above <br />the mine portals has been designed with a slope of .002, or 1.7 inches of drop <br />in 100 linear feet. It seems unlikely that such accuracy can be maintained <br />during construction and it is likely that ponding will occur along the ditch, <br />which will result in excessive saltation. Therefore, the following <br />stipulation is required. <br />Stipulation No. 3 <br />WITHIN THREE MONTHS OF PERMIT ISSUANCE, THE PERMITTEE MUST SUBMIT TO <br />THE DIVISION NEW DESIGNS ALLOWING FOR A GREATER SLOPE ON CHANNEL A TO <br />INSURE FLOW THROUGH THE CHANNEL LENGTH. THE PERMITTEE MUST COMMIT TO <br />INSPECTION OF THE DITCH AFTER RUNOFF EVENTS TO LOCATE AREAS OF <br />EXCESSIVE EROSION. THE PERMITTEE MUST ALSO COMMIT TO APPROPRIATE <br />EROSION PREVENTION IF NEEDED. <br />Stream Channel Diversion <br />The permanent diversion of the ephemeral drainages located above the refuse <br />embankment has been designed with a slope of.001, or .8 inches of drop per 100 <br />linear feet. A slope this low will not ensure proper drainage and will likely <br />require high maintenance to clean the channel of sediment deposition. The <br />Division does not feel this slope meets the requirement of Rule 4.05.4(4) to <br />construct the permanent diversion "with astable longitudinal profile". Since <br />