Plans for the Musina Dam

• The report does not offer a preliminary on-site geotechnical investigation for recommended dam and weir sites (meaning that there could be unanticipated difficulties for construction which may affect costing and construction time). • The report does not sufficiently address options for institutional arrangements and associated compliance with legislative requirements (nor does it give an estimate of how long it will take to navigate the regulatory requirements). In particular, it is not clear through what process permission from the three other Limpopo riparian countries to construct the weir and also pump a large amount of water from the Limpopo will be sought, and how long that may take. • The study does not report on any possible engagement with prospective investors such as municipalities, the Department of Water and Sanitation or Lepelle Northern Water to consider integration with existing water supply infrastructure in the area.

Plans for the Musina Dam

The plan for the Musina Dam starts with the construction of a weir in the Limpopo main stem, just downstream of the Beit Bridge. This weir will enable taking up to 60% of the Limpopo’s flow, leaving 40% for “ecological requirements” downstream. This is 60% of the estimated flow of 1714 Mm3, which comes to around 1 026 Mm3 .

An earlier claim that only “flood waters” will be harvested is not referenced in the pre-feasibility study. A multi-purpose dam with the main function of flood protection, the Mapai dam, is being planned further down on the Limpopo and closer to the floodplains themselves, in Mozambique.

There is a marked seasonal flow pattern in the Limpopo, with high flow from November to April, and a much lower flow (around 10% of the high flow) in the other six (winter) months. The plans suggest that there will be pumping from the Limpopo in the winter months as well. As explained in the previous report (Munnik 2020), the Limpopo River and its shallow and deep aquifers are interconnected, therefore abstraction particularly in the winter months will affect the system as a whole.

According to the proposal for the Musina Dam, the Limpopo River water will then be pumped to a settling dam, and from there into the Musina and Sand River dams. The pumps will require 130 MW and 208 MW respectively. From here, it will be pumped further to the SEZ site about 50km south with a head of about 260m.

Fig 2: Musina and Sand dams as presented in the pre-feasibility study. Map by Toni Olivier.

The Musina Dam is the smaller of two dams that are planned. Its dam wall is designed to be 45 m high and 488 m long across the Sand River, projected to yield 13 Mm3/a without Limpopo water, and 57 Mm3/a with the Limpopo water. Because Limpopo River water has a high sediment 25