PERMFILE51254 - Laserfiche WebLink

Home Browse Search

r 1 1 1 1 4.4 ROADS Roads represent a significant portion of the area to be disturbed by American Soda over the life of the Yankee Gulch Project Erosion and sediment controls will be implemented during construction, operation and reclamation phases to ensure that adverse environmental impacts associated with roads are minimized. Erosion and sediment controls and methods to be used during road construction, use and elclamadon are detailed below. In the construction phase silt fences (Fgure 1), straw bale filters and check dams (Figure 2 and Fgure 3), geotextile fabrics (Figure 4), and temporary drain structures (Fgure 5) will be used to control erosion and sedimentation. To minimize sedimentation and control erosion, low water crossings with culverts sized to pass base flow conditions and adequate surfacing materials will be used where permanent roads are located across intermittent or peremial streams (Fgure 6). Additionally, perennial strearrr crossings will allow adequate freeboard for inlet head to allow all weather use of roads. Ephemeral stream low water crossings may use durable surfacing materials with or without culvert installation at Arerican Soda's discretion. To ensure uninterrupted use during the operational phase, roads will be constructed to meet prescribed specifications. To promote safety, facilitate the smooth flow of traffic, reduce road and equipment maintenance costs, and to promote structural stability, road specifications will require adequate crowning or sloping to ensure positive drainage from the traveled surface, and provide adequate erosion and sediment control structures and practices to safely convey surface water runoff away from roads. Typical road layouts include embankment, side hill, cut slope and gentle slope topography drainage situations (Figure 7). During a road's operational life, maintenance activities will be performed to ensure that proper surface configurations are maintained Surfacing will be of adequate thickness and durable materials capable of supporting the types and amounts of traffic expected to use the road during its use period. Surfacing materials will also minimize or prevent erosion and sedimentation from the road's surface. Drainage systems will be provided for roads which are capable of safely carrying runoff from roads into undisturbed drainage channels. Road drainage systems will typically include the use of ditches, berms, diversions and channels of various configurations and sizes (Fgure 8); drop stmctures (Fgure 5); water bars (Figure 9); and culverts (Fgure 10) with outlet protection as needed (Figure 11) to achieve positive drainage and protect the integrity of the roadbed. When culverts are used, particular attention will be given to providing adequate slope to ensure that installations are self-cleaning since natural sediment loads are high and culverts are easily plugged. Channel linings in road drainage features will be specified and placed as necessary to control erosion and sedimentation (Fgrue 12). Channel linings that may be used individually or in combination include soil, vegetation, geotextile fabrics or rock rip-rap depending upon flow velocities and channel configuration. ' Water bars may be used to protect roads from erosion during operational use, and during restoration and reclamation. When used, water bars will be located to take advantage of low points or dips in the road surface. Their outlets will avoid loose fills and will discharge to ' stable areas whenever possible. Water spreaders will be used at the outlet ends when necessary. Typical spacing for water bars based on road slope and erosion hazard are provided in Table 4. ' Following closure of each mining panel, reclamation activities will include the removal and restoration of road corridors. When roads are retired their surfacing materials will be salvaged ' Americm Soda, LLP. Q-4 Soil Coaarvation, Fiosion and Sediment Convol, Redamatloa and Revegetadoo flm ' October 28. 1998