Issued by: Department of Water Affairs and Forestry
WARNING: OWNERS MUST ENSURE DAM SAFETY
26 JANUARY 1996
Many smaller, privately owned dams are in danger of failing this summer because the necessary dam safety precautions are not in place. The Department of Water Affairs and Forestry has issued a warning to dam owners to check that maintenance work on their dams are in order. Many smaller dams are not maintained as prescribed by the dam safety regulations contained in the Water Act. The unusually good rainy season creates possible danger of dams failing. This may result in a "domino-effect" where dams failing upstream cause failures of dams further downstream. Several farm dams have already failed due to inadequate spillway capacity.
Good rains have fallen over large areas, many catchment areas of dams are saturated and many dams are full or nearly full. For large parts of the country the months of normal good rain still lie ahead. This season the rainfall intensity has been very high on small localised areas, which causes heavy flooding.
All dam owners are advised to check the overall condition of their dams in order to minimise dam failures. In cases where dam safety inspections have been carried out in terms of the dam safety legislation, special attention should be given to recommendations made in the reports. Dam failures can lead to loss of life and property and are not in the interest of the country.
Spillways that are too small are one of the commonest defects of existing dams. Dam owners are warned to check that spillways have adequate capacity to take floods, and are free from obstructions such as trees, shrubs and sandbags. Earth or brick walls that have been constructed across spillway entrances and do not form part of the original design of the dam, must be removed. Low spots on the crest of earth dams should be filled with suitable material properly compacted in thin layers, to the general level of the remainder of the embankment. This is to ensure that the full freeboard is available during floods.
Dam owners who have operation and maintenance manuals with contingency/emergency plans for their dams must ensure that the documents are readily available and up to date with respect to emergency preparedness. This is vital to enable an owner to provide the South African Police Service, civil defence organisations and local authorities with relevant information about the dam, at short notice, to assist them with their duties.
ENQUIRIES: MR J H NORTJE TEL: (012) 299 2423
OR MR A G CHEMALY (012) 299 2409