ECM for Cropped Environments - Terracing


A terrace is an embankment constructed perpendicular to a slope to provide a barrier for water flowing down the slope as shown in the diagram. Terraces are often built following the curvature of the land. The presence of terraces reduces erosion by reducing the slope length and thereby reducing water runoff velocity as shown in the diagram below. The presence of terraces increases water infiltration and reduces runoff that can potentially erode soil. Excess water collected on the terraces drains either through a buried underground pipe system such as tile or through grassed waterways. Terrace building can be quite costly because it involves moving large quantities of soil and land grading to change the slope length.

Slope% = rise/run (that is, how high the slope is divided by how long the slope continues for)

The velocity of water increases as slope length increases. Decreasing slope length by planting rows perpendicular to the slope or by adding terraces can decrease the velocity of water and, as a result, decrease its erosive potential. Images by UNL


A terrace in Sarpy County, NE. Image by USDA-NRCS

Terraces and no-till farming work to control erosion on a farm in Montgomery County, Iowa. Image by USDA-NRCS