Erosion TTool/Implementation of runoff retention zones (RRZ)

Technical articles - Erosion TTool - Érosion des sols

Grandes cultures Grandes cultures Erosion TTool

Illustration of the practice of implementing a runoff retention zone within the serious game Erosion TTOOL. Credit: Delphine Hombrouckx

The runoff retention zone (RRZ) is a water storage and infiltration structure. It allows temporarily retaining a large volume of water over a wide but shallow surface. It is a structure for the protection of property and people.

Description

Advantages

• Limits runoff and stores water.
• Easy to implement and easy to maintain.
• Can improve biodiversity.

Disadvantages

• Subject to regulation.
• Significant implementation cost.
• Loss of cultivable area / valorization of prairie.

Implementation

• This development must be carried out on an agricultural plot upstream of inhabited areas.
• It can be of various types but it is preferable that the water retention be temporary. It can notably be a natural floodable prairie: example in Gers at Isle Jourdain: https://www.oieau.fr/eaudoc/system/files/34239.pdf (page 6).
• The development often requires the creation of a mound as well as an outlet which must allow draining the structure within 24 or 48 hours.
• The entire surface must be grassed to promote soil deposits.

Cost

• Depends on the structure.

• Implementation: several thousand euros

• Maintenance: €460/ha for mowing