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Communication incl. Poster: BibTeX citation key:  Okparaa
Okpara, J. N., Perumal, M. & Andrés-Hernández, M. D. 2009. Modeling the Impacts of Climate Change on Water Resources of Niger River Basin Using Artificial Neural Networks Synergy. Work presented at Third International AMMA Conference, July 20—24, at Ouagadougou, Burkina Faso.
Added by: Devic 2009-09-23 09:48:28    Last Edited by: roussot 2009-10-16 18:00:31
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Categories: General
Keywords: Climate
Creators: Andrés-Hernández, Okpara, Perumal
Publisher: African Monsoon Multidisciplinary Analyses (Ouagadougou, Burkina Faso)
Collection: Third International AMMA Conference

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Abstract
The study attempts to explore and assess the potential impacts of climate change on the hydrology and water resources of Nigerian sector of Niger River basin, with simulation models- Thornthwaite water balance accounting scheme and Artificial Neural Networks (ANNs). The water balance model uses mean monthly climate variables of precipitation, temperature, net radiation, as well as soil water holding capacity and potential evapotranspiration, for estimating water surpluses of five Niger sub-basins and linking these water surpluses of these sub-basins with the corresponding observed monthly average discharges that is dependent on precipitation over the basin using the Artificial Neural Networks (ANNs) model. Arcview GIS offered a vital means for the hydrological modeling, especially the building of grid containing the water holding capacity parameter of the soil, creating climatic surfaces and merging various spatial themes (data layers) that were useful in the interpretation, analysis (soil water budgeting) and change detection of spatial structures and objects. Ninety six monthly data have been used for calibrating the ANNs and twenty four months data were used for verification. Areally averaged temperature and precipitation changes from formulated climate change synthetic scenarios were imposed on each sub-basin for assessing climate change impacts on runoff (water surplus). Results show discernible evidence and the sensitivity of the Niger River basin to the changing climate, annual water surplus is highest only over the Niger south (1241.2mm), followed by Lower Benue (973.6mm), Lower Niger (729.4mm) Upper Benue (495.3mm) sub-basins and the least value is observed at Upper Niger Sub-basin(360.7mm). It is further observed that the water surplus is much more sensitive to the accuracy of potential evaporation estimate (that depends on temperature) in the humid climate than the arid climate. Using synthetic climate change scenarios, it is observed that when temperature increases by 2oC, the mean monthly runoff on the average is expected to change by -10 to -50%, -5 to -40% and 15 to 60% respectively for precipitation changes of -20%, 0% and 20%. By implications then, water, hydro-power, health and food security of the country may be seriously threatened by climate change, unless rainfalls turnout to be on the increase and adequate management strategy put in place. Necessary adaptation measures and nonconventional sources of water that can be exploited in the future are also highlighted.
Last Edited by: roussot