It is proposed that one or two of
Mphanda Nkuwa’s four electricity–generating turbines would be operated
intermittently to provide for peak energy demands in South Africa,
Mozambique’s large neighbor. This operating practice would cause daily
fluctuations in river levels downstream, ranging in magnitude from 0.5 to
2.8 meters depending on proximity to the dam. The impacts of these changes
in river level would be felt for over 100 miles downstream and affect
thousands of people dependent on the river for their livelihoods. The
Mphanda Nkuwa Environmental Impact Assessment warns, "intermittent turbine
operation will infringe the rights of people to ’clean’ water, fish, safe
travel, and flood recession farmland."
Mozambique simulated these
mini–floods in June 2001 by releasing water from the upstream Cahora Bassa
Dam. The rising waters eroded clumps of vegetation from the riverbank
throughout the duration of the four–day experiment. If Mphanda Nkuwa was
built and operated in this fashion, it would put the area’s most
productive agricultural land (pictured below) at risk of flooding and
erosion. Subsistence farmers in the Zambezi Valley depend heavily on these
riverbank gardens ("baixa land") for food security. Moreover, the daily
fluctuations would further complicate life for downstream populations by
making fishing and navigation more difficult.
Downstream sandbars, which provide
important habitat for wildlife (including the rare African Skimmer bird)
would be severely eroded by these mini–floods. Fish and numerous
invertebrate species could be either directly affected by the flooding or
through resulting habitat loss. Experts also fear that reeds (an important
building and craft material) and some rare plant species would be
jeopardized.