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<br />The essential hydrologic functions of the Colorado River AVF are those geo- <br />logic, hydrologic, topographic, and soils characteristics that give the area <br />the ability to support flood irrigated agricultural activities. Subirrigation <br />is a marginal function that is limited to a fee of Che lower areas taut are <br />also capable of flood irrigation. Since no mining activities will take place <br />within the AVF, the geologic, topographic, and soils characteristics of the <br />alluvial valley floor will not be affected. Hater quality in the Colorado <br />River stream/alluvial aquifer system could may be slightly degraded but the <br />ability to flood irrigate the alluvial valley floor would not be affected. <br />Cumulative Hydrologic Impacts <br />There are no other active mines is the vicinity of the Roadside aad Cameo <br />!"lots aad no mines are anticipated. There are tea abandoned mines vi thin the <br />permit area, the Old Cameo Hine and the Blue Flame Yl nes. The Old Cameo Hine <br />is stratigraphically lover than the Colorado River and is located North of <br />it. The Blue Flame '.line is located south of the river aad adjacent to the <br />Roadside Mine. The downdip portion of this mine is flooded most of the year <br />since it underlies Rapid Creek and is hydraulogically connected due to effect <br />of subsidence. During winter it has been observed by the writer to be dry. <br />The company says appro~timately 0.47 cfs of mine discharge eater is added to <br />the Colorado River, increasing its net floe by O.OLZ. It has been determined, <br />based on all available information, thaC the mine discharge will not increase <br />the flow in the Colorado River. Moat of the eater pumped from the Cameo mine <br />originates from the Colorado River by way of aquifers located below the <br />alluvium of the river. The eater pumped from the Roadside *fine would <br />naturally contribute to base flows in the Colorado River through aquifer <br />discharge into the river. This situation would occur even without mining in <br />the area. <br />The effects of mine discharge on river eater quality is to increase the amount <br />o_' soluble salt in the Colorado River by about 0.1X, and Sacrease dissolved <br />ferrous material by 0.2X, with no measurable effect on pH. Heavy metal <br />concentrations should not increase since heavy metals are relatively insoluble <br />at the pH levels found in the discharge eater. All these effects are <br />considered minimal and will no*_ significantly decrease the eater quality in <br />the Colorado River, but aonitori~ will continue to make sure these effects do <br />oat change. <br />-10- <br />