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Road Stream Crossing Best Management Practices

Problem: Road/stream crossings that are poorly designed or outdated can contribute tons of sand to a stream channel, especially with rain and snowmelt. Typical problems at road crossings include:
  • Undersized culverts
  • Steep approaches on dirt roads
  • Old bridges and culverts that are breaking down
  • Steep embankments that are not vegetated well
  • Excessive foot traffic at crossings to access streams
  • The culvert or bridge is the “low spot”, thus causing runoff to pool and flow directly into the stream
Common BMP solutions include:
  • Paving and curbing to channel runoff and prevent erosion of the roadbed
  • Spillways to channel runoff into nearby lowland areas
  • Larger culverts to better
    accommodate stream flows and channel widths
  • Longer culverts to prevent steep, eroding embankments that may be difficult to revegetated
  • rsc2_berm.gifBridges or bottomless culverts to allow for natural stream bottoms
  • Fieldstone at inlets and outlets for slope stabilization
  • Geotextile on embankments for revegetation
  • Raising the roadbed so that the crossing itself is not the low spot.
  • Berms to prevent runoff from running over the edge of the road
  • Check dams and ditching
rsc3_culvert.gifCulverts are commonly undersized to handle stream flows, and can cause big pools to form as a result.
Open Bottom Arch or Box Culvert:
rsc4_archbox.gifWider, longer, bottomless arch and box culverts are an ideal way to accommodate stream flows, especially during high water events.
Multiple Culverts:
rsc5_multiculvert.gifMultiple culverts are not ideal as some of them can get easily blocked with branches and debris.
rsc6_bridge.gifBridges are the proper structure for crossings on larger rivers and streams.
Steep Dirt Approaches:
rsc7_steepdirt.gifSteep approaches on dirt roads constantly dump sand into rivers with rain and snow melt.
Pavement and Curbing:
rsc8_pavecurb.gifPavement and curbing is the ideal way to prevent erosion of the actual roadbed into the stream.
rsc9_spillway.gifSpillways with rock at the end of curbing allows runoff to filter into nearby low areas.
Check Dams:
rsc10_checkdam.gifCheck dams are a series of rock piles placed in vegetated ditches that slows runoff and filters out sediment.
Run Off:
rsc11_runoff.gifOur transportation system can be a major source of sediment to our creeks and rivers.
This page last updated on 12/13/2011.