Three Cheers for Water Bars (the Forest Road Structures)

You are driving (slowly and with caution, of course) along a quiet, unpaved forest road and admiring the scenery and then — ka-pow — your tires roll into a dip and then over a high bump. The dip and bump are parallel to each other but span the road at an angle. What gives? You just drove across a water bar, a drainage structure that Washington state forest practices rules might require to control water runoff and reduce erosion on forest roads.

A water bar diverts the direction of water and prevents erosion
A water bar diverts the direction of running water and prevents erosion. Photo: DNR

The newly updated Forest Practices Illustrated–an overview of forest practices rules that the Washington State Department of Natural Resources (DNR) enforces on 13 million acres of state and private forestlands–explains how to construct water bars. These structures require maintenance, so they are best used on lightly traveled back roads.

How to build a water bar and why

Water bar cross section
Cross section of a water bar from DNR’s Forest Practices Illustrated. Graphic: DNR.

The purpose of a water bar is to send water from a road and into a nearby ditch, forest floor or vegetated area. The goal is to make water move more slowly across the road surface so it does not send sediment into ditches, streams, wetlands and other areas.

Water bars are among the several alternatives to culverts and other expensive and intrusive structures when roads are built for forestry and other forest practices.

Water bars also help to:

  • Protect road surfaces
  • Protect fill slopes
  • Return water to its natural course
  • Reduce water velocity
  • Protect the discharge point from erosion

Keep an eye out for water bars the next time you are cruising down a quiet forest road. Your back and your vehicle’s suspension system will thank you.

See an overview of these and other important rules for forestry and other forest activities in newly updated Forest Practices Illustrated. This free download is an overview of rules DNR enforces on 13 million acres of state and private forestlands in Washington state to protect streams, wetlands, clean water, habitat and public resources, such as highways, utilities and built structures.