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The road system for the site will stay very similar to the existing site. The only new roads will be <br />along the west boundary of the site to allow for topsoil handling and light duty traffic. <br />4. Hydrolopy and Sediment Control for Mining <br />The major hydrologic design item for this operation is to safely pass runoff from the irrigated <br />pasture land uphill from the operation to the west and north. The stormwater runoff will be <br />controlled by a set of ditches, isolation berms and major storm water channels. The berms will <br />allow the pit bottom to serve as a sediment pond for all storm events within the disturbed area. <br />The diversion ditches provide the necessary isolation by carrying all upstream runoff away from <br />the site. <br />There are 6 ditches used for isolation. See Map C-213. The collection ditches will be V-ditches of <br />1.5 feet depth and 2H:1 V side slopes cut out of the natural gravel. In most areas no lining will be <br />needed due to the mild slopes of the site. Where ditches encounter steep grades, a rip-rap lining <br />will be used. Ditch #1 controls water encountered in the southern portion of Mining Area 2 from <br />the west. The water from this ditch will be channeled to the unnamed natural drainage to the <br />southwest of the permit area. Ditch #2 drains the next northern area which goes through two <br />culverts at CR 305. Ditch #2 will discharge into the Grass Lined Channel #2. The large gully <br />currently in this location will be slowly filled during the pit's life using naturals produced by the <br />crushing/screening process. The design of the channel can be seen below. Ditch #3 will collect <br />the stormwater that falls between CR 305 and the 2H:1 V slope. Ditch #3 will also discharge into <br />the Grass Lined Channel #2. Ditch #4 will collect stormwater that falls between the access road <br />for the pit and the relocated gas line. Ditch #4 will discharge into the Grass Lined Channel #1. <br />Ditches #5, 6 will be installed once the center pivot field if fully backfilled. See Map F for the <br />location of these ditches. These ditches will collect stormwater and excess irrigation water from <br />the center pivot field. Ditches #5, 6 will discharge to the irrigated pasture on the reclaimed pit <br />floor. During large events this water will drain past the pit floor and be collected by Grass Lined <br />Channel #1. The ditches will remain in place after reclamation and are therefore designed for a <br />100 year 24 hour event. They primarily have small drainage areas. <br />Cugnini Pit, November 2009 D-7