DAMS & HYDROPOWER

SSI has designed more than150 dams, across a spectrum from arch type to concrete gravity, concrete buttress, earthfill, rockfill, masonry or combinations of these, to small low cost earthfill embankment type agricultural dams.  We have commissioned more than 30 large dams including buttresses up to 44 m high, concrete mass gravity walls, double curvature arches up to 37 m high and various earthfill and rockfill walls - as well as a large geomembrane lined dam (4 million m²) and a dam featuring the then largest Hydroplus units in the world. Medium sized concrete masonry dams are also our speciality, as are economical masonry structures using labour-intensive construction methods. We have also undertaken safety inspections for more than 25 impoundments - several classified as High Hazard Category III dams.  SSI engineers in South Africa and Zimbabwe are certified Approved Professional Engineers for dam safety inspections and rehabilitation.  Our expertise incorporates: Hydropower schemes Dams Hydropower schemes Transference scheme

PROJECTS Mohale Dam Project, Lesotho Highlands Water Scheme, for Lesotho Highlands Development Authority (LHDA). SSI’s involvement is as part of the design and construction stage joint venture, Mohale Consultants Group, MCG, comprising Harza Engineering (USA), Snowy Mountain Engineering Corporation (Australia), Highlands Engineering consultants (RSA), BKS Pty Ltd, Melis & du Plessis, Nippon Koei Co (Japan), SM Consulting Engineers (Lesotho) and SSI. The project incorporates a concrete faced rockfill dam approximately 145m high and a diversion system comprising two horseshoe shaped Diversion Tunnels with upstream and downstream cofferdams.  The dam wall itself consists of an embankment containing some 7,2 million m3 of rockfill materials, with a concrete lined ungated spillway on the left abutment and a multiple draw-off compensation water intake structure and outlet works.  This type of wall construction is unique to this part of the world but is well known and popular in China, Australia and North and South America.  Contact Jacques du Plessis jacquesd@ssi.co.za (012) 367-5800