Table 1: Driekoppies dam main features Dam type Combined earthfill with uncontrolled spillway Maximum wall height 50m Embankment length 2400m Gross storage capacity 251Mm3 Full supply level 328.5m above sea level Surface area at full supply level 1870ha Catchment area 900km2 Volume of concrete 201,300m3 Volume of embankment 4.7Mm3 Annual incremental system yield 140Mm3 at 80% assurance Natural mean annual run off 272Mm3 Present mean annual run off 216Mm3 Estimated total cost US$73.6M Construction period 57 months Source: Swaziland Komati Project Enterprise