Best Practice

Terrace & WASCOB

Practice Overview

A system of ridges is designed and built on a hillside to slow down, collect, and divert surface runoff to prevent erosion. Designs vary by site based on topography and land use.

Water and Sediment Control Basins or “WASCOBs” accomplishes the same goal with smaller embankments and a system of intakes and pipes.  

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  • Reduced erosion
  • Reduce surface runoff
  • Sediment capture

How It Works

In farmable fields with moderate to high slopes, a system of ridges/embankments is used to block the path of surface runoff. The water is diverted to a designated area where it can flow downhill over a much less erodible surface such as a grassed waterway. Water is slowed which reduces sheet erosion, and gully erosion is minimized when water is diverted to a designated waterway.

WASCOB designs are meant to block the water, hold it in a basin, and slowly release it through an underground pipe system. This allows sediment and debris in the surface water to settle out before moving downstream which reduces nutrient and sediment transport.

Depending on the site and design, the ridges can be shallow enough to farm atop so loss of production acres is minimized.

Installation Considerations

  • Most efficient on fields with slopes of 2 to 18%
  • Ideal for sites with irregular topography
  • Must have fertile soil without shallow bedrock
  • Plan for working width of farm equipment
  • Must be maintained to limit buildup of sediment and debris