Erosion TTool/Creation of a channel (or swale) and a mound
From Triple Performance
Swales (swales) are closed ditches, equipped with an overflow that temporarily stores runoff water at the top of the plots. They are generally shallow, have gentle slopes, and are vegetated.
Description
Advantages
- Allows to channel runoff.
- Channels water and promotes infiltration into the soil.
- Retention of water.
- Limits flood risks and reduces water flow.
- Reduces the risk of drought.
- Serves as a buffer zone during rainy episodes and floods.
Disadvantages[1]
- Loss of agricultural surface.
- Regular maintenance is essential.
- Possibility of contamination of the groundwater.
- Risk of silting up.
Implementation
- The soil must be compacted to resist incision by water into the soil and thus avoid erosion.
- Soil working lines and wheel tracks must respect the original topography in order to guide runoff water.
- There are several types of swales:
- The vegetated swale which has permanent and dense vegetation allowing high roughness.
- The swale with ridges which consists of small transverse mounds creating a succession of compartments pouring into each other (slows the flow).
- A concrete example in Gers (Arton): Noue.
Advice[2]
The dimensions of swales are to be determined by:
- The desired storage capacity.
- The local topography.
- The available surface.
- The depth of the recessed area is at most 0.5 m.
