|Special Public Works Programmes - SPWP - Anti-Erosion Ditches - Training Element and Technical Guide for SPWP Workers, Booklet No. 1 (ILO - UNDP, 84 p.)|
Every year, before the start of the rainy season, the farmer must check the condition of the retaining banks. The main causes of deterioration of the banks are:
- the run-off of rainwater, leading to gullying of the banks;
- the base of the embankment being eroded away by the flow of water (diversion network);
- backfill material becoming packed down;
- gaps forming in the banks due to the water overflowing;
- damage caused by animals crossing over the structures..
Maintenance consists, therefore, of:
- checking that the embankments are still horizontal. Surveying rods can be used for this in the way described earlier in the section dealing with the construction of ditches;
- reinforcing any places where the structure has become weak, by adding earth and compacting as required;
- filling in any gullies or gaps with earth and compacting well.
A close and constant watch should be kept on the slopes to ensure that the protection afforded by grass or vegetation remains adequate.
All weeding and scraping of the surface of the slopes must be strictly avoided. However, if any trees prevent the grass or vegetation growing as it should, they must be cut down.
Price: 10 Swiss francs