scholarly journals Optimising hydropower development and ecosystem services in the Kafue River, Zambia

2018 ◽  
Vol 69 (12) ◽  
pp. 1974 ◽  
Author(s):  
Ian G. Cowx ◽  
Alphart Lungu ◽  
Mainza Kalonga

Fisheries are an important resource in Zambia, but are experiencing overexploitation and are under increasing pressure from external development activities that are compromising river ecosystem services and functioning. One such system is the Kafue Flats floodplain, which is under threat from hydropower development. This paper reviews the effect of potential hydropower development on the Kafue Flats floodplain and explores mechanisms to optimise the expansion of hydropower while maintaining the ecosystem functioning and services that the floodplain delivers. Since completion of the Kafue Gorge and Itezhi-tezhi dams, seasonal fluctuations in the height and extent of flooding have been suppressed. This situation is likely to get worse with the proposed incorporation of a hydropower scheme into Itezhi-tezhi dam, which will operate under a hydropeaking regime. This will have major ramifications for the fish communities and ecosystem functioning and is likely to result in the demise of the fishery, along with destruction of the wetlands and associated wildlife. To redress the problem, it is recommended that an environmental-flow study is conducted, as initiated by World Wildlife Fund, to protect provision of the existing ecosystem services and optimise hydropower development, thus ensuring sustainability of the aquatic resources of the Kafue Flats for future generations.

2017 ◽  
Vol 68 (9) ◽  
pp. 1741 ◽  
Author(s):  
Ibon Aristi ◽  
Joanne E. Clapcott ◽  
Vicenç Acuña ◽  
Arturo Elosegi ◽  
Holly Mills ◽  
...  

Toxic cyanobacterial proliferations in water bodies can cause serious environmental and public health issues, as well as having economic effects. Increased inputs of nutrients and fine sediment caused by forestry have been hypothesised as possible causes of increased Phormidium-dominated proliferations in New Zealand rivers. Little is known about the effect of these proliferations on river ecosystem functioning. In the present study, we evaluated five sites along the Maitai River (New Zealand) differing in pine plantation cover of their catchments. We hypothesised that Phormidium biofilms would trap more sediments and recycle more phosphorus than diatoms, that Phormidium proliferations would increase with forestry cover in the catchment and that the varying abundance of Phormidium would affect river ecosystem functioning. Phormidium did not trap more sediment or recycle more phosphorus (measured as alkaline phosphate activity) than diatom biofilms. However, the cover of Phormidium did increase with the proportion of forestry in the catchment. Organic matter decomposition rates (measured as loss of tensile strength of standard cotton strips) varied very little among sites, whereas river ecosystem metabolism increased with the abundance of Phormidium, especially in the lower part of the river. The results of the present study suggest that pine forestry does promote Phormidium biofilm abundance and affect ecosystem functioning in the Maitai River.


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