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WATER INFORMATION EXHIBIT G <br />1. Surface Water General Discussion <br />The surface water features within and near the permit area are the Gunnison River which is <br />approximately 50 feet north of the permit boundary at the closest point, and ponds created by <br />gravel mining. FEMA has not published a 100 year flood plain for this stretch of the Gunnison <br />River. The excavation is located approximately 30 feet above the normal elevation of the river. <br />All surface water from up to a 100 -yr 24 -hr event will be contained on site through the use of <br />sediment ponds, diversion ditches and reclamation islands which will work as catch benches. <br />The surface water will be contained from the disturbed area to prevent sediment from being <br />transported of site. <br />When mining reaches the bedrock, if a natural channel does not exist in the bedrock, a channel <br />will be installed via a dozer and ripper. This will be done to maintain the pre -mine surface water <br />drainage patterns. Mining around the drainage channel for SWB 6 (See Map G) will stop far <br />enough away ( -10 feet) to maintain the drainage as the low point in the stormwater basin. <br />2. Hydrolo2v and Sediment Control for Mining <br />Water that is encountered in the pit will not be released from the site. The only water that will be <br />found within the disturbed area is stormwater runoff and water used in the wash plant. The <br />runoff that needs to be collected for the entire site is shown in the calculation below: <br />Runoff Curve Number and Runoff Fri Oct 28 10:03:54 2011 <br />Project: Western Pond Runoff By: B. Langenfeld Date: <br />10/28/11 <br />Location: Craig Ranch Pit Checked: Date: <br />Present <br />1•. Runoff Curve Number (CN) <br />Cover description CN Soil Group Area(Acre) <br />Desert Shrub (Poor) 88 D 45.077 <br />Desert Shrub (Poor) 88 D 7.196 <br />Desert Shrub (Poor) 88 D 17.504 <br />Craig Ranch Pit, March 2011 G - <br />