Laserfiche WebLink
WORWEST ENGINEERING EVALUATION OF LTC ROAD <br /> JULY 28,2016 <br /> COR PORAT ION PAGE 6 OF 10 <br /> Potential Impacts and Mitigation <br /> Development of the Hitch Rack Ranch Quarry could potentially impact the condition of Little Turkey Creek <br /> Road, and a discussion of these potential impacts and how the quarry has been designed to minimize the <br /> impacts is included below. The evaluation of impacts and mitigation relies on guidelines and <br /> recommendations in the Gravel Roads Construction&Maintenance Guide prepared by the Federal Highway <br /> Administration (FHWA, 2015). This guide indicates that three basic elements are required to properly <br /> maintain a gravel road, and Little Turkey Creek Road contains none of these. Each of these is related to <br /> providing adequate drainage from the road, as potholes and washboards are typically the result of poor <br /> drainage from the road surface(FHWA,2015). The recommend road cross section is shown in Figure 7. <br /> 1. A crowned surface <br /> 2. A shoulder that slopes away from the driving surface, and <br /> 3. A ditch <br /> S hn Wdor <br /> Road wurfocc <br /> lddW <br /> ll �c�i Subgrade -3itch 1 <br /> Figure 7: Roadway Cross Section (FHWA,2015) <br /> Increased Erosion <br /> Potential Problem:Increased runoff from developed areas could increase water on Little Turkey Creek Road <br /> and increase erosion of the road surface. <br /> Solution: The quarry design includes a water management system that is designed to convey runoff from <br /> the 100-yr,24-hr storm event through detention basins and then into Little Turkey Creek or Deadman Creek. <br /> The discharge from the detention basins is set to drain the basin over a 72-hour period.This flow is a reduced <br /> flow rate from the natural flows and helps to remove sediment and erosion from the peak flows. This <br /> drainage system is specific to the disturbed area around the quarry and is separate from any drainage along <br /> Little Turkey Creek Road. Therefore, no waters from developed quarry areas will reach the existing road <br /> surface,and there will be no increase in erosion from the proposed mine on Little Turkey Creek Road. <br />