Seite - 1346 - in Book of Full Papers - Symposium Hydro Engineering

provides a summary of both large as well as small dams. The most important conclusions are as follows:  With regards to large dams, only earthfill and tailings dams (no large concrete dams) have failed in South Africa. With regards to small dams, the large majority of failures are earthfill dams although some smaller concrete weir structures have also failed.  Overtopping due to inadequate spillway discharge capacity as well as piping and internal erosion make up the large majority of causes of incidents at and failures of small dams 4. CONCLUDING REMARKS From the lessons learnt from the implementation of dam safety legislation in South Africa the following is of importance:  It is of prime importance to convince political decisions makers about the necessity for Dam Safety implementation including the necessary legislative and regulatory environment.  It takes time and significant resources to successful implement a dam safety regulatory system – for example after more than 30 years existing dams are still being registered in South Africa. It also takes time and effort to classify the dams as well as establish regulatory compliance;  Dam Safety legislation, enforced by dedicated and experienced officials (in the DSO), has a positive correlation with the decrease in the number of incidents and failures of dams built since promulgation of dam safety legislation in South Africa. This has also ensured the formal recording of incidents and failures. Not all incidents and failure of especially small dams are however reported to the DSO as required. ACKNOWLEDGEMENTS The authors wish to express their gratitude to all other present and past members of the Dam Safety Office as well as Sub-directorate Dam Safety Surveillance of the DWS that contributed in some or other way to the development of the above-mentioned paper. 1346