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EXHIBIT G WATER INFORMATION ~ ~_:._.~:: ~ -a, :~:~.._ ._. _. ~ ~__ ~._~ _~_~~~ _,m.r - This exhibit summarizes information related to water issues, including potential impacts on surface water and groundwater, water supply, potential wetlands issues, and how storm water will be managed. The exhibit is supported by additional disussions in Appendices A, E, F, H and I. The following subsections aze included in the exhibit • Surface Water • Groundwater • Water Quality • Water Quantity • Waters of the U.S./Wetlands • Surface Water Management Plan SURFACE WATER GCC Rio Grande, Inc. (Rio Grande) has collected climatological data at the site for more than two years. These data, along with the National Weather Service and county USDA Soil Conservation Service data, show that there is approximately 10 to 12 inches of precipitation per year. It is reported by local residents that the specific site may have less total rainfall. However, precipitation rates of 1 inch per hour have been observed, and this can generate relatively large-volume runoff. The site is divided by at least nine separate arroyos. This drainage pattern drains the entire surface of the mining area to the north and northeast. The receiving stream is the St. Charles River that flows east to the • Arkansas River. Some small, existing arroyos have been eroded to The limestone bedrock, while others have a gentler slope that contain several feet of silUloam soil where mnoff is moderate to slow. Surface water will be diverted or captured to prevent accelerated erosion. A sedimentation pond will be constructed as stated in the storm water plan (Appendix F) to capture surface water that enters the surface mine area. Sediment will settle out and the clarified water will be pumped to the connecting arroyo and allowed to continue to the St. Charles River. GROUNDWATER There are no existing shallow water wells producing water for either livestock or human consumption within two miles of the proposed permit area. Extensive shallow drilling throughout the property has demonstrated that there is no significant ground water contained within the geological formations that will be affected by the proposed surface mine. An old springhouse located at the Blake Ranch has been abandoned; however, it is surmised that surface water infiltrates the Ft. Hays Limestone at a higher elevation point in the same arroyo, delivering minor amounts of water in very wet yeazs. Drilling was conducted to explore the soils, overburden (Smokey Hill Shale), the Ft. Hays Limestone, and the Codel Sandstone (upper member of the Carlile Shale Formation). No free standing water was observed in any of the open core holes. In most cases, water circulation used to remove cuttings from the holes was lost, due to the fractured nature of the Ft. Hays Limestone. Exhibit C-7 illustrates the generalized geologic column in the immediate vicinity of the site. • The first confined aquifer on site is the Dakota Sandstone, which lies 450 to 490 ft below the Ft. Hays 1180-MinePertnit Exhibits (1W.05.@)FQJAL.doc G-1 July 8, 2002