1.6 BMP C107 - Construction Road/Parking Area Stabilization
Stabilizing subdivision roads, parking areas and other onsite vehicle transportation routes immediately after grading reduces erosion caused by construction traffic or runoff.
Stabilize roads or parking areas wherever they are constructed, whether permanent or temporary, for use by construction traffic.
Install fencing (see BMP C103 - High Visibility Fence), if necessary, to limit the access of vehicles to only those roads and parking areas that are stabilized.
1.6.3 Design and Installation Specifications
On areas that will receive asphalt as part of the project, install the first lift as soon as possible.
Use one of the following methods to stabilize the area immediately after grading or utility installation.
Apply 6-inch depth of 2- to 4-inch crushed rock, gravel base, or crushed surfacing base course.
Apply a 4-inch course of asphalt treated base (ATB).
Apply cement or calcium chloride 1.
Apply a 6-inch depth of hog fuel (only if the area will not be used for permanent roads, parking areas or structures).
Whenever possible, place construction roads and parking areas on a firm, compacted subgrade.
Temporary road gradients shall not exceed 15 percent. Carefully grade roadways to ensure no water will pond on the roadway surface. Provide conveyance ditches on each side of the roadway in the case of a crowned section, or on one side in the case of a super-elevated section. Direct conveyance ditches to a sediment control BMP.
Rather than relying on conveyance ditches, it may also be possible to grade the road so that runoff sheet flows into a heavily vegetated area with a well-developed topsoil. Landscaped areas are not adequate. If this area has at least 50 feet of vegetation, then it is generally preferable to use the vegetation to treat runoff, rather than a sediment pond or trap. The 50 feet shall not include wetlands. If runoff is allowed to sheetflow through adjacent vegetated areas, it is vital to design the roadways and parking areas so that no concentrated runoff is created.
Protect stormwater system inlets to prevent sediment-laden water entering the stormwater system (see BMP C220 - Stormwater System Inlet Protection).
Inspect stabilized areas regularly, especially after large storm events.
Add crushed rock, gravel base, hog fuel, etc. as required to maintain a stable driving surface and to stabilize any eroded areas.
Following construction, restore all areas to preconstruction condition or better to prevent future erosion.
No tracking of sediment onto the roadway is allowed. If sediment is tracked onto road, clean the road thoroughly by shoveling or pickup sweeping.
1. If cement or cement kiln dust is used for roadbase stabilization, pH monitoring and BMPs are necessary to evaluate and minimize the effects on stormwater.