Modeling future flows of the Volta River system: Impacts of climate change and socio-economic changes

Li Jin; Paul G Whitehead; Kwasi Appeaning Addo; Barnabas Amisigo; Ian Macadam; Tamara Janes; Jill Crossman; Robert J Nicholls; Matthew McCartney; Harvey J E Rodda

doi:10.1016/j.scitotenv.2018.04.350

Modeling future flows of the Volta River system: Impacts of climate change and socio-economic changes

Sci Total Environ. 2018 Oct 1:637-638:1069-1080. doi: 10.1016/j.scitotenv.2018.04.350. Epub 2018 May 14.

Authors

Affiliations

¹ Geology Department, State University of New York College at Cortland, Cortland, NY 13045, USA. Electronic address: li.jin@cortland.edu.
² School of Geography and the Environment, University of Oxford, Oxford, UK.
³ Department of Marine and Fisheries Sciences, University of Ghana, Accra, Ghana.
⁴ CSIR-Water Research Institute, Box AH 38, Achimota, Accra, Ghana.
⁵ Met Office, FitzRoy Road, Exeter EX1 3PB, UK.
⁶ Department of Earth and Environmental Sciences, University of Windsor, Windsor, ON, Canada.
⁷ Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ, UK.
⁸ International Water Management Institute, PO Box 2075, Colombo, Sri Lanka.
⁹ Hydro-GIS Ltd, 10 Coles Lane, Chalgrove, Oxfordshire OX44 7SY, UK.

PMID: 29801202
DOI: 10.1016/j.scitotenv.2018.04.350

Abstract

As the scientific consensus concerning global climate change has increased in recent decades, research on potential impacts of climate change on water resources has been given high importance. However in Sub-Saharan Africa, few studies have fully evaluated the potential implications of climate change to their water resource systems. The Volta River is one of the major rivers in Africa covering six riparian countries (mainly Ghana and Burkina Faso). It is a principal water source for approximately 24 million people in the region. The catchment is primarily agricultural providing food supplies to rural areas, demonstrating the classic water, food, energy nexus. In this study an Integrated Catchment Model (INCA) was applied to the whole Volta River system to simulate flow in the rivers and at the outlet of the artificial Lake Volta. High-resolution climate scenarios downscaled from three different Global Climate Models (CNRM-CM5, HadGEM2-ES and CanESM2), have been used to drive the INCA model and to assess changes in flow by 2050s and 2090s under the high climate forcing scenario RCP8.5. Results show that peak flows during the monsoon months could increase into the future. The duration of high flow could become longer compared to the recent condition. In addition, we considered three different socio-economic scenarios. As an example, under the combined impact from climate change from downscaling CNRM-CM5 and medium+ (high economic growth) socio-economic changes, the extreme high flows (Q5) of the Black Volta River are projected to increase 11% and 36% at 2050s and 2090s, respectively. Lake Volta outflow would increase +1% and +5% at 2050s and 2090s, respectively, under the same scenario. The effects of changing socio-economic conditions on flow are minor compared to the climate change impact. These results will provide valuable information assisting future water resource development and adaptive strategies in the Volta Basin.

Keywords: Africa; Climate impacts; Ghana; Modeling; River flow; Water resources.