Diversion ditches intercept water from cut banks and carry water away from crowned roads. Cross-drain culverts move water collected in ditches from seeps and insloped roads across roads for nonerosive discharge down slopes. They will need to be cleaned of soil and leaves periodically. Pipe culverts are more expensive than open-top box culverts, but they are the best choice for permanent roads. Broad-based dips handle cross drainage and drainage from the road surface and are a less expensive alternative to culverts.
Dips slope outward to divert water down slopes.
As with cross-drain culverts, spacing depends on the road grade. Allow roads to settle for two or three months before they are used. Suspend logging operations during extremely wet periods. Have a professional supervise all aspects of design, construction, operation, and retirement of the transportation system. Many timber harvesters are trained in proper road design and installation.