Downstream and Coastal Impacts of Damming and Water Abstraction in Africa

Abstract

Anthropogenic factors associated with damming and water abstraction, and the resultant environmental pressures, are reviewed in six African river catchments using records and forecasts of climatic, demographic, and land-use change. Changes in the states of the flow regime through catchment drainage systems to the coastal sea are considered in conjunction with climate change and other human-induced pressures. The impacts of these changes on downstream and coastal environments and their communities are described in past, present, and future perspectives. Linkages between the issues and the pressures of damming and water abstraction are appraised and scientific, policy, and management responses proposed aimed at remedying existing and perceived future negative impacts. The study proposes that there is a need to integrate catchment and coastal management to account for the whole water flow regime together with its human dimensions. Management priorities relating to the operation of existing damming and abstraction schemes and planning of future schemes include the following: consideration of ways in which water discharges could be adjusted to provide improvements in downstream and coastal environmental and socioeconomic conditions; addressing the problem of sediment trapping impacting on the sustainability of dam reservoirs; and assessment of downstream and coastal impacts of future schemes in the light of climate change forecasts.

The impacts of hydropower development on rural livelihood sustenance

“…These roles are highly dependent on the river continuum, which is profoundly affected by river damming (Vannote, Minshall, Cummins, Sedell, & Cushing, 1980). River damming is increasing at unprecedented rates with millions of reservoirs having been constructed globally in the last century (Smith, 1971;WCD, 2000) to harness water for electricity generation, domestic or industrial use, food production, navigation, fisheries, and recreational as well as for flood control purposes (Graf, 2002;Snoussi et al, 2007).…”

“…This is necessitated by the fact that more than 1.6 billion people are still without access to electricity, while 1.1 billion people are without access to a reliable water supply (United Nations Development Programme (UNDP), 2006). Moreover, water and electricity have been recognized as essential resources for promoting economic growth and enhancing community livelihood (Snoussi et al, 2007;Yüksel, 2009). The UNDP has also emphasized the importance of affordable energy in the developing world as a critical input for the realization of Millennium Development Goals by the year 2015 (UNDP, 2006).…”

Sustainable water management - perspectives for tourism development in north-eastern Morocco

“…open channels) • Health problems due to poor water quality • River dams lead to reduced recharge causing sea water intrusion Alonso-Almeida, 2012; Boelee & Laamrani, 2003;Bzioui et al, 2010;Carneiro et al, 2008;Carneiro et al, 2010;Doukkali, 2005;Fetouani et al, 2008;Tekken et al, 2009;Tekken & Kropp, 2012 Climate Change • Increase in the frequency of droughts • Disturbances in hydrological cycle • Precipitation decrease, temperature increase • Higher evapotranspiration rates • Increasing wind erosion • Coastal inundation and sea water intrusion into coastal aquifers due to sea-level rise • Siltation of river dams Bzioui et al, 2010;Kadi, 2004;Moustadraf et al, 2008;Schilling et al, 2012;Snoussi et al, 2002;Snoussi et al, 2007;Snoussi et al, 2008;Schyns & Hoekstra, 2014;Tekken et al, 2009;Tekken & Kropp, 2012 criteria or indicators for water management, nor measures to secure water supply in cases of water shortage situations. The description of sustainability lacks a commitment towards the specification of concrete water resources protection measures.…”

“…The water situation has become more than temporarily critical, thus mainly caused by shifting climate patterns, increasing economic activities and associated population growth, agricultural water use and decreasing levels of groundwater and its degradation, e.g. due to salinization (Carneiro et al, 2008;Snoussi et al, 2007;Snoussi, Ouchani, & Niazi, 2008;Fetouani, Sbaa, Vandoosterc, & Bendra, 2008).…”

Methodology for geohazard assessment for hydropower projects

“…The imposed changes in sediment load can lead to riverbed degradation directly downstream, while the imposed changes in flow can lead to narrowing of river channels and decreased sediment transport capacity (ICOLD 2009a). Also, damming a river can increase coastal erosion by reducing sediment supply to the coast (Slagel and Griggs 2008;Snoussi et al 2007;Bohannon 2010).…”