Recommended design countermeasures for coastal roads exposed to severe overwash conditions
Based on our research to date, the USA CTEREC recommends four countermeasures to reduce the likelihood of damage to coastal roads in hurricanes:
- Locate the road back in the expected sand "deposition" area during barrier island overwash (see the typical post-storm elevation picture below). This will remove the road from the most severe, direct wave attack and scour problems.
- Lower the elevation of the road to match the surrounding sand elevations. The goal is to avoid the "weir-flow-damage mechanism" and to encourage the road to be buried by sand early in the storm.
- Build a sand dune immediately seaward of the road to provide some limited protection and a reservoir of sand for road burial in overwash events.
- Incorporate buried shoulder protection into the road such as was done with the buried revetment in the USA CTEREC's full-scale lab tests. To see this design sketch, click here.
