Page - 1343 - in Book of Full Papers - Symposium Hydro Engineering

environmental impact assessment (EIA). One of the conditions of the water use licence is the environmental authorization. In other words, no listed activity at a dam may take place before receiving the necessary environmental authorization. 3. LESSONS LEARNT FROM LONG TERM IMPLEMENTATION OF DAM SAFETY LEGISLATION According to the latest database of the DSO [14] a total number of 5 462 dams with a safety risk according to the Dam Safety Regulations were registered in South Africa at the end of February 2018 (see Table 4). The large majority of these dams (more than 75.3%) can be classified as small (less than 12 m high) while only 3.46% can be classified as high. The rest is classified as medium dams. When comparing the number of dams with the ICOLD definition of a small dam it is evident that there are 458 dams between 12 m high and 15 m high. Table 4 General dam statistics (using the South African definition for height) Height of dam (from the river bed level to the highest point of the dam) (m) Number of dams Less than 12 m 4 158 12 m to < 15 m 458 15 m to < 30 m 672 30 m and higher 174 Total 5 462 It is important to note that of the 5 462 dams registered, 5 434 dams have been classified by the DSO. Of these 5 434 dams, 57.3% are Category 1 dams that does not require any further regulatory actions other that registration and classification. The remaining classified dams consist of 36.3% Category 2 dams and 5.4% Category 3 dams - both Categories requiring the involvement of an APP and a supporting professional team (for Category 3 dams) and 0.9% dams that does not warrant a classification. In other words, a significant portion of small dams are classified as Category 2 dams due to their adverse hazard ratings. Fig. 1 provides a graphical presentation of the number of dams registered as well as classified annually since the inception of dam safety regulations in 1986. As expected a large number of dams were registered within the first 5 years (2 632 dams in total). What is however interesting to note is that although the number of dams registered per year has decreased since, the number of annual registrations basically stayed constant since 2000. An increase is evident since 2012 – this could be attributed to the implementation of the revised dam safety regulations in 2012 with an increased focus of the so-called dirty water dams. It has taken another 1343