Erosion and Sediment Pollution Control Program Manual.pdf

ROADSIDE DITCH - Sediment Removal Efficiency: VERY LOW. This device is not an ABACT for
special protection watersheds, but may be used to make other BMPs that are ABACT work more
effectively. In most cases, the ditches paralleling temporary access roads and haul roads need not be
lined if sufficient ditch relief culverts are provided, erosion resistant soils are present, and flow velocities
are less than 2 feet per second (fps). However, protective liners are required for roadside ditches
discharging to special protection waters, where discharging directly to surface waters, or where
necessary to prevent the erosion of the channel itself. A typical cross-section for a roadside ditch is
shown in Figure 3.1.
USDA Forest Service
USDA Forest Service
FIGURE 3.1 - Typical Roadside Ditch Section
FIGURE 3.2 - Access Road Layout
Sizing and spacing of ditch relief culverts should be according to Table 3.3. Rock filters are not
required where roadway surface is stabilized, ditches are provided with protective liners, and cut banks
are stabilized. Suitable outlet protection should be provided at each culvert outfall.
363-2134-008 / March 31, 2012 / Page 30