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WATER INFORMATION <br />1. Surface Water General Discussion <br />EXHIBIT G <br />The surface water features within and near the permit area is the unnamed drainage which is <br />approximately 300 feet east of the mining area boundary. Existing stormwater on the terrace <br />either infiltrates through the gravel or runs off through the un -named drainage. Surface water <br />within the disturbed area will be collected during mining within the pit area and will evaporate or <br />infiltrate. SWMP Area 2 on Map G will drain to a sediment pond which discharges to a drainage <br />to the west. No sediment will be allowed to leave the site and cloud any downstream waters. The <br />site will not affect existing water rights, since the pit will not expose groundwater and will not <br />store stormwater for more than 72 hours. <br />After reclamation, stormwater encountered in the mining area will continue to runoff, infiltrate <br />or evaporate. <br />2. Hydrology and Sediment Control for Minim <br />The only water that will be found within the disturbed area is stormwater runoff and water <br />hauled to the mining area and used in processing and for dust control. <br />2.1 Uphill Runoff <br />Berms will be installed along the south side of the site to divert uphill runoff around the site. <br />These berms can be seen on Map C -2, along with the stormwater basins that flow towards the <br />site. Table G -1 shows the stormwater runoff that each basin will generate (100 -YR, 24 -HR <br />event), which has to be redirected by the berms. In some areas, ponding will occur against the <br />berms, but this is unavoidable due to the rolling natural topography. <br />The 100 -YR event precipitation for this area is 2.60 inches (from NOAA Atlas 2, Volume 3). A <br />curve number (CN) of 58 is used since the soil type uphill of the site, 7C- Morapos Loam, has a <br />high available water capacity (9.2 inches) and is deep (up to 60 inches). Additionally the land use <br />in this area is hay meadow, which limits runoff. See Appendix 1 for the Soil Report on this site. <br />Based on the above inputs, the runoff for these stormwater basins is 0.158 inches deep. The <br />runoff in SWB -1 and -7 will flow along the berms (1 foot tall, and 3 foot tall respectively) away <br />Hayden Gravel Pit, May 2013 G -1 <br />