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Problem: Road/stream crossings that are poorly designed or outdated can contribute tons of sand to a stream channel, especially with rain and snowmelt.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

 

• 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
• Bridges 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

Culverts:
Culverts are commonly undersized to handle stream flows, and can cause big pools to form as a result.

 

 

 

 

 

 

Open Bottom Arch or Box Culvert:
Wider, longer, bottomless arch and box culverts are an ideal way to accommodate stream flows, especially during high water events.

 

 

 

 

 

Multiple Culverts:
Multiple culverts are not ideal as some of them can get easily blocked with branches and debris.

 

 

 

 

 

 

Bridges:
Bridges are the proper structure for crossings on larger rivers and streams.

 

 

 

 

 

 

Steep Dirt Approaches:
Steep approaches on dirt roads constantly dump sand into rivers with rain and snow melt.

 

 

 

 

 

 

Pavement and Curbing:
Pavement and curbing is the ideal way to prevent erosion of the actual roadbed into the stream.

 

 

 

 

 

 

Spillways:
Spillways with rock at the end of curbing allows runoff to filter into nearby low areas.

 

 

 

 

 

 

 

 

Check Dams:
Check dams are a series of rock piles placed in vegetated ditches that slows runoff and filters out sediment.

 

 

 

 

 

Run Off:
Our transportation system can be a major source of sediment to our creeks and rivers.