|Special Public Works Programmes - SPWP - Anti-Erosion Ditches - Training Element and Technical Guide for SPWP Workers, Booklet No. 1 (ILO - UNDP, 84 p.)|
|3. Different types of anti-erosion ditches|
There are many types of anti-erosion ditches and ridges. The engineer will decide which type is most suitable for the land in question. In deciding, he will take into account:
- rainfall intensity;
- the nature of the soil;
- the slope of the land.
The choice of ditch is not necessarily final and can be modified to take local experience and opinion into consideration.
Without going into detail on the choice of structure, a few basic considerations must be observed.
The choice of structure depends above all on:
- the slope of the land;
- the permeability of the soil;
- the use to which the land is put (type of crop).
Steeply sloping land (greater than 25%)
This type of land is primarily pastureland or forest. On land such as this, the purpose of anti-erosion structures is to protect the cultivated land which lies below. The appropriate structures here are ditches or terraces, in conjunction with tree plantations or silt catchment pits.