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Adequacy Items <br />SIIB AGRA Project E92-7075 <br />~~~ Page 11 <br />~~ 6i <br />There are no plans to mine beyond the limits indicated on Figure C-2. Provisions <br />will be incorporated in the surface water control plan to divert upland surface <br />flows around the pit azea and to contain runoff from disturbed azeas on the mine <br />site. <br />b. The operator provided surface water subbasin areas. No peak flows were calculated <br />for the unnamed stream channels. Please provide the peak flows for these channels <br />and the entire sub water basins. The following criteria must be used to determine <br />peak flows. <br />1. Acreage of watershed. <br />2. Type of soil. <br />3. Type of vegetation. <br />4. Slope of the drainage area or hydraulic length for the evaluation should also <br />include the impact the mining operation is going to have on the overall <br />drainage water supply contribution to the irrigation ditches and canal due to <br />the creation of a large pit or quarry. <br />Peak flows for the drainage basins shown on Figure G-3 of the Permit Application that <br />are within the mine azea aze summarized on Table A. Calculations of the peak flow were <br />• made using the Rational Method and aze presented in Appendix 11. Currently the Supply <br />Canal intercepts runoff from the majority of the Dowe Flats drainage basin. This runoff <br />would be reduced by the amount intercepted by the azea protected by the mine surface <br />water diversion facilities. <br />c. The operator stated on Page 3 Fust paragraph that "because the drainages are all <br />ephemeral and rarely flow, gauging stations have not been established on the project <br />site". However on Figure G2, Northwest of DFMW-1, there appears to be a <br />gauging station located. If it is a USGS gauging station, there probably is water <br />quality and flow data for the station. Please provide the data. Since the gauging <br />station is outside of the permit area and the two quames are located up stream of <br />the gaugiug station, it will give the Division additional data to make an educated <br />determination of the impact your quarry will Gave on downstream water users. <br />The only gauging station indicated on Figure G-2 is located in the SW1/4, NW1/4 of <br />Section 2, T3N,R70W. This station is located on the Little Thompson River which is in <br />a totally different geologic and hydrologic setting than the site. Data from this station is <br />irrelevant to the subject site. <br />d. On page 3, in the last paragraph the operator stated "The results of the historical <br />surface water quality analysis for SVC-1 and SVC-2 are summarized in Table G4." <br />Table G4 has only water quality data for SVC-1. Where is the water quality data <br />. for SVC-2? Where are these monitoring locations located on the map or Figure G <br />2? <br />L, A G R A <br />Earth & Environments/Group <br />