allAfrica.com: Mozambique: Mphanda Nkuwa - Threat Or Opportunity ? (Page 1 of 2)

A campaign by some environmentalists is now under way to deprive Mozambique of one of its most attractive potential sources of electricity, a new dam on the Zambezi at Mphanda Nkuwa, about 70 kilometres downstream from the existing dam at Cahora Bassa.

The latest argument raised by groups such as Justica Ambiental (Environmental Justice) is that the government is supposedly hiding information about Mphanda Nkuwa. Last week they demanded that the government publish the environmental impact study on the project.

They seemed unaware that in March 2002 the Hydro-electric Project Technical Unit (UTIP) of what was then the Ministry of Mineral Resources and Energy publicly presented the findings of that study at a well-attended meeting in a Maputo hotel. The study gave Mphanda Nkuwa a fairly clean bill of health.

One of the great advantages of Mphanda Nkuwa is that the river here tumbles through a deep ravine: this geology means that the artificial lake created by the dam will be small, covering only 100 square kilometres. This compares with the 2,675 square kilometres of Lake Cahora Bassa. As for the oldest dam on the Zambezi, at Kariba, on the Zambia/Zimbabwe border, that lake drowned 5,577 square kilometres of land. This gives Mphanda Nkuwa a much more favourable lake-to-power ratio than either Cahora Bassa or Kariba.

Quite correctly, Justica Ambiental notes that 1,400 people will be displaced by the new dam. But this is a relatively small number. When these families were asked, they expressed an interest in moving to new villages built near the shores of the dam lake, provided they are adequately compensated.

They were also interested in the employment opportunities brought by the dam. Currently there is virtually no waged labour in the Mphanda Nkuwa area, and the inhabitants scratch out a living from subsistence agriculture.

The dam construction will provide 3,000 temporary jobs - more than the entire population of the area. This is an unprecedented inflow of money into a very poor part of Tete province.

Once the dam is complete, however, it will only provide 80 permanent jobs. The lake could provide perhaps 60 other jobs in semi-industrial fishing (just as there is a thriving fresh water fishery on Cahora Bassa lake).

There will be new roads to the dam, and a bridge over the river.

The impact study noted that this "will reduce rural isolation, and will improve local people's access to markets".

Justica Ambiental raises questions about the impact of the dam on downstream activities, arguing that it would cause daily fluctuations in the level of the river.

This is a genuine problem. According to the study, the effects downstream will be nil - but only when the turbines are operating continually (which will be whenever the flow of the river exceeds 1,600 cubic metres a second). Under these conditions the amount of water leaving Mphanda Nkuwa will be the same as that which currently leaves Cahora Bassa.

The problem will arise if, for any reason, the turbines can only operate intermittently. Then, the study said, at Tete city there could be a daily fluctuation in the height of the river of more than 80 centimetres (the current figure is less than 20 centimetres). This level of fluctuation could cause erosion of the river banks and of Zambezi sand banks, which in turn would affect wild life, the quality of the river water, agriculture, and navigation on the river.

The study said that additional research into these impacts would be needed, to establish guidelines for any loss of water rights by people living along the river.

Mitigation of this problem, to ensure a reasonably constant flow of the river, implies good coordination between Kariba, Cahora Bassa and Mphanda Nkuwa, and careful management of discharges.

Set against this problem is the role that Mphanda Nkuwa could play in eliminating catastrophic floods on the lower Zambezi.

UTIP has argued that, if the Kariba and Cahora Bassa dams were forced to open their floodgates at the same time, the rush of water downstream could be halted at Mphanda Nkuwa.

Perhaps the most far-fetched of Justica Ambiental's arguments is that there is a serious earthquake risk to a dam built at Mphanda Nkuwa. It cites as evidence the earthquake of 23 February 2006 in central Mozambique, with its epicentre in Machaze district, Manica province.

Measuring 7.5 on the Richter scale, this was the strongest earthquake on record in the southern African region. But if such an earthquake is regarded as a threat to Mphanda Nkuwa then it is equally a threat to Cahora Bassa - and the existing dam was undamaged. Even more significant, the Chicamba Real dam on the Revue river, much closer to the epicentre of the quake, was also unscathed. The engineers who design dams are not fools, and build them to withstand enormous stresses.

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