How stone bunds are used in agroecology
A set of stone boulders are arranged in the trench to form a V-shaped canal. Small stones are put in the V-shaped canal to behave like stone filters. This arrangement is repeated till a height of 30 cm to 45 cm is attained depending on the slope, the slope length and availability of stones.
Source: http://www.iwmi.cgiar.org/africa/West/projects/Adoption%20Technology/Soi...