Useful Definitions

Bedload: the sand, gravel, boulders, or other debris transported by rolling or sliding along the bottom of a stream.

Channel Deflector or Vane: act to guide flow away from bank, reduce bank erosion, promote local sedimentation and encourage vegetation growth.  Common names and designs include j-hooks, rock barbs, and single- or double-wing deflectors.

Debris Flow: a moving mass of mud, sand, soil, rock, water and in the case of wildfires, woody material (tree branches of all sizes) that travels down a slope under the influence of gravity.

Ephemeral Stream: ephemeral portions of streams flow only in direct response to precipitation.  Dry washes and arroyos are generally classified as ephemeral streams.

Fill slope: the surface area formed where soil is deposited to build a road or trail.

Hillslope: Hill side.

Inslope (road): grade slopes toward inside ditch.

Outslope (road): grade slopes toward fill slope.

Outsloping: the downhill side of a road where the side of the road slopes with the hill at or near the natural contour and runoff is allowed to drain down the hill without being channeled into a ditch or other water-control device.  Outslopes are usually associated with a road in steep terrain which is literally cut into the side of the hill.

Overside Drains: pipes, downdrains and spillways used to protect slopes against erosion by collecting surface runoff and conveying it down the slope to stable drainage.

Road Template: the shape and cross-sectional dimensions of a roadway.

Runoff: Movement of water across surface areas of a watershed during rainfall events.

Slope/Grade: refers to the inclination of a physical feature, landform or constructed line to the horizontal.