Impacts of hydropower dam operations in the Mana Pools National Park floodplains

摘要

The Mana Pools flood plain along the Middle Zambezi River and part of the popular Mana Pools National Park of Zimbabwe has been experiencing both ecological and morphological changes since the construction of upstream hydropower reservoirs. This study investigated the hydro-dynamics from natural and human influenced flows, particularly at the Mana Pools floodplains which are downstream of Kariba and Kafue hydropower dams. Descriptive statistics were used to analyse the differences in flow regime upstream and downstream of the hydropower reservoirs. A standard t-test was done to compare the natural and modified mean annual flows. Results show that the presence of upstream reservoirs has reduced the high peak average monthly flows by 17% and increased the average monthly low flows by 5% at Mana Pools. However, the mean annual runoff has not significantly changed. Results also established that. In line with recent calls for ecological considerations in reservoir management, the study recommends that the reservoir operation in the Middle Zambezi River should mimic the pre-impoundment Middle Zambezi River flow regime at Mana Pools.