Highway embankments constructed within a floodplain may require stabilization to resist erosion during flood events. You may design and construct embankment stabilization with the initial roadway project where the need is obvious or the risk of damage is high. In other locations the following factors may warrant that installation of embankment stabilization to be delayed until a problem actually develops as follows:

Highway channel stabilization measures are usually local in nature. Engineers design them primarily to protect the highway facility from attack by a shifting channel or where the floodplain adjacent to the facility is highly erodible.

If a highway location adjacent to a stream cannot be avoided, you should evaluate protective measures to determine the measure best suited to the situation. These alternatives may include channel change, roadway embankment protection, stream bank stabilization, and stream-training works.

Channel stabilization should be considered only when it is economically justified and one or more of the following basic purposes will be accomplished:

Stabilization measures at the highway site may not be successful if the section is located within long reaches of unstable channel. Local stabilization often results in high maintenance costs and repetitive reconstruction. A stream may respond to local stabilization by changing flow regime or attacking the unprotected bed or opposite bank. The potential for these occurrences should be considered. However, if bank erosion occurs only at isolated locations, stabilization measures at these locations are probably an economical solution even though a period of repetitive maintenance may follow.