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• Purpose and Scope of this Exhibit 7, Item 17 <br />The Item addresses topsoil stockpile 15G located within reclamation block EP015. The <br />topsoil is needed for reclamation of nearby Haul Road A, and therefore must remain in <br />place for the immediate future. Its entire watershed is small, approximately 3.1 acres. Of <br />this 3.1 acres, 2.7 acres drains onto the lands proposed for bond release. The remaining <br />0.4 acres is the portion of the access road to the topsoil pile that drains westerly toward <br />Haul Road A. The area addressed here includes the 2.7 acre footprint of the pile itself <br />and those portions of the access road leading to it that drain northerly onto lands <br />proposed for bond release. The current configuration of this area is shown on Exh. 7 -17, <br />Figure 1. <br />Because of its small size and the generally gentle slopes surrounding it, runoff form this <br />disturbance can be accommodated by means of an exemption as provided for in Rule <br />4.05.2 (3). The measures described in the following section demonstrate that adequate <br />sediment control can be provided for the area by means of a low earthen berm to be <br />constructed around the downstream limits of the topsoil pile. To prevent the berm from <br />impounding water longer than necessary to drop the suspended sediment, the design <br />includes an internal gravel drain extending through the berm, acting essentially as a check <br />dam. <br />Modeling using SEDCAD attached herewith indicates that the facility will prevent <br />• release of suspended sediment onto the reclaimed lands, as described in more detail <br />below. <br />Description of the Alternative Sediment Control System <br />The system includes a low earthen berm, 4 feet in height at its maximum section, to be <br />constructed immediately downstream of the topsoil pile, and shallow v- ditches or <br />drainage swales or to conduct all runoff from the access road and the topsoil pile <br />footprint into the area behind the proposed berm. The location and layout are described <br />in Exh. 7 -17, Figures 1 and 2. <br />The berm will provide alternate sediment control for the upstream 2.7 acres of topsoil <br />pile and access road. The pile is currently stabilized with a vegetative cover. The more <br />critical time frame is in the future when the pile has been removed and final graded but <br />the permanent vegetation cover on the regraded site is not yet mature. <br />The presence of the internal gravel drain as shown in the detail within Fig. 2 allows the <br />facility to drain freely after runoff events. The entire system is intended to be left in <br />place after the topsoil pile and access road have been removed and reclaimed. Because <br />of its low height and flat slopes (3H:1 V) it will blend into the surrounding reclaimed <br />topography. <br />Exh. 7 -17 -2 Revision No.: TR -90 <br />Revision Date: 04/13/11 <br />