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Erosion Control
example of a highway shoulder
bladed of all vegetation
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example of rill erosion which can
appear on a bladed highway shoulder
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Watershed management on highway corridors is complicated by the fact that highway surfaces shed all intercepted precipitation onto roadside surfaces, where it flows over the shoulder as rainwater or snowmelt. Without vegetative groundcover discharges begin a process of sheet and rill erosion (picture on right) that not only has the potential to undercut the paved surface, but also collects and carries silts and fine soil particles into the roadside drainages and culverts. These in turn grow into larger and faster flows that carry heavier particles that accelerate erosion and scouring, ending at some point with a discharge into a stream, riparian area, wetland, lake or reservoir.
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Natural Resources Management focuses on maintenance and/or repair of check dams, wattles (fence structure), erosion mats, mini-benches, and stabilization of exposed soils by seeding, and installation of geotextiles.
Photo right: example of organic erosion mats and aspen logs, AZ SR 73.
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Flow velocity. Water velocities have to be maintained to ensure that water retention on road surfaces is prevented to avoid impediment of tire friction resulting in hydroplaning during the summer (monsoon) storm season or ice formation during the winter months.
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Prescott, Indian Fire, erosion
control block. |
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Filtration of soil particles by vegetation and or detention devices. If wild-land fires occur, we are responsible for installing erosion mitigation measures to reduce the possibility of drainage culverts bescoming plugged with soil, vegetation, or debris.
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Percolation of as much water as possible into the soil profile for purposes of vegetation maintenance and ground water recharge ensuring that the remaining water enters the hydrologic system in a relatively clean condition. |
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