NATURAL ENVIRONMENT AND HERITAGE
The constituent programmes include Integrated Catchment Management, Environmental Resource Conservation; and Environmental Resource Monitoring.
Integrated Catchment Management: This includes the establishment of Catchment Management Authorities, Environmental Awareness and Recycling of Waste Material).
Environmental Resource Conservation: This includes programmes such as conservation of the endangered species. One such sepcies is the Maluti Minnow (pseudobarbus quathlambae).The Maluti Minnow Project is very high profile. The Minnow is classified as a critically endangered species and the entire world distribution of the Minnow is restricted to the Lesotho Highlands.
Environmental Resource Monitoring: The water quality monitoring program has been running smoothly since inception.
PUBLIC HEALTH PROGRAMME
The Public Health teams were established to promote and maintain the health of communities affected by the LHWP. This was achieved through provision of health care services to the construction workforce and the local communities, creation of awareness on dangers of drug abuse, provision of adequate clinical facilities, referral and evacuation systems for the construction workforce, prevention and control of communicable diseases and provision of clean water and sanitation.
Phase 1A: Katse Muela Transfer Tunnel
Water enters this 45km-long tunnel through the operating gates of the 98m-high Intake Tower, of which only the access bridge, platform deck and operating room remain above the surface level of the waters of Katse Dam, within sight of the Malibamatso bridge. The tower has intake 'windows' at four different levels below the surface, so that the best quality water can be transferred, depending on the level of the reservoir.
The original plans for the transfer tunnel required a minimum of 6km of the structure's length to be lined with concrete, for structural support. Instability in the exposed basalt convinced the engineers that lining the full 45km of the Tunnel with 300mm thick concrete would be a safer, if more expensive option. The lining was completed by late 1996.
Phase 1B: Mohale Katse Tunnel
This 4.5m diameter, 32km long tunnel links the two major Phase 1 reservoirs, allowing water to flow in either direction, and keeping each dam at optimum operating level.
The delivery tunnel is made up of two sections: the Delivery Tunnel South, from the 'Muela power station to the Lesotho- South Africa border, and the Delivery Tunnel North, from the border to the Ash River Outfall in South Africa.
Construction of the Delivery Tunnel South went smoothly. The 15km tunnel boring machine (TBM) excavation was completed 20 months ahead of schedule, realizing a saving of M85,7 million on the original R421,6 million contract. Included in the structure are two steel-lined sections that form the crossings under three rivers. Under the Ngoajane River is an l8m section of pipe housing the flow meters that measure the volume of water delivered from Lesotho to South Africa. This part o(the tunnel was the first part of Phase lA to be completed.
The 22km-long Delivery Tunnel North was also completed ahead of time (by three months) and under budget (a R52 million saving). Only one TBM was used, with the tunnel being lined concurrently with precast concrete segments, thus saving time. The first section of the tunnel, under the Caledon River (the South Africa-Lesotho border) was constructed using traditional drill-and-blast techniques, and is steel-lined.
Phase 1B: Diversion Tunnel
Another means of increasing Katse reservoir's supply level and the efficient transfer of water to South Africa, the Matsoku Weir and Tunnel, will divert a maximum of 55m3/sec into the dam, so increasing the yield delivered to South Africa by a maximum of 2,2m3/sec.
A base flow of 600 litres/sec will continue down the river at all times, with water only being diverted during periods of peak flow. It is expected to be in operation by the second half of 2001.
The Matsoku Tunnel is 5,6km long, and is being constructed using drill-and-blast techniques to maximize employment for local Basotho labor. It is being lined with 75mm thick steel-fiber reinforced shotcrete. A slight downhill gradient towards Katse ensures that the facility will be gravity-fed.
The weir, 180m long and 20m high, is a solid mass (21 000m3) of concrete. Water is directed by an in-stream ledge towards a fore-bay on the left side of the weir (on picture above). Here, the base flow passes through while the excess water enters the tunnel.
The weir's downstream face features a series of large steps, designed to dissipate the energy of water overflowing the weir.
The construction contract was due to be completed by April 2001.
The hydropower plant at ‘Muela, in the northern Botha-Bothe District, was constructed as part of Phase 1A of the LHWP. The major benefit now derived from ‘Muela Hydropower Station is that Lesotho generates her own electricity needs.
Technically, the station consists of the 60m x 1.30m x 15m underground power house cavern that accommodates three transformers, and three turbine generators rated at 24 Mega Watts (MW) each. The Station is fed water by the Katse Reservoir via a 45km-long concrete lined transfer tunnel measuring 4.35 metres in diameter.
On the surface, there is the Operations Building that houses the control room to monitor and operate the ‘Muela Hydropower Station.The building also houses operations and maintenance staff offices and workshops.
Basically, the power generation process is effected via water that passes through the hydraulic turbines as the prime mover for the generators. Water is then discharged through the draft tubes and concrete lined connection tunnels into a 40 metres high downstream surge chamber and through 1.7km long tailrace tunnel into ‘Muela Reservoir. From the reservoir, water is conveyed by delivery tunnels via ‘Muela Intake Structure to the tunnel outlet at Ash River in South Africa. From the Ash River water flows into the Wildge River and then to the Vaal River.