Nexus: Water-Climatehttp://repository.pauwes-cop.net/handle/1/782024-03-28T16:35:25Z2024-03-28T16:35:25ZScanning Climate Change Impacts on Water Resources of the Largest African River BasinsAhmed, Shamseddin Musahttp://repository.pauwes-cop.net/handle/1/512020-01-28T13:13:15Z2018-01-01T00:00:00ZScanning Climate Change Impacts on Water Resources of the Largest African River Basins
Ahmed, Shamseddin Musa
The objectives were to ensemble and analyze the projected signals of climate change recently published in peer reviewed outlets with respect to five African river basins, viz. Nile, Senegal & Volta, Niger, Congo, and Zambezi & Limpopo. Results of 55 papers were assessed (distributed as 30, 25, 16, 13, an d 16%, respectively). Findings stated the dominant tendency for using unmitigated emission pathways (A2 for the Nile and RCP8.5 for the remaining basins), with fewer applications to hypothetical scenarios. Compared to the individual member, the majority of the papers followed the ensemble GCMs approach to obtain robust results compared mostly (40-50%) to the 1960-1990 baseline. Nevertheless, all models agreed in the increasing trend of temperature compared to the dominant uncertain trends in rainfall. The studies applied 19 hydrological models (especially SWAT, HBV and CLiRuN) coupled with limited land use considerations. In contrast to uncertain trends in future rivers’ flow, all basins showed decreasing trends in runoff. This discrepancy in climate change projections delayed the adoption of adaptation plans. Technically, runoff, stream flows and evapotranspiration terms were largely misused. The north-south cooperation is direly needed in building observational datasets, a priori input for characterizing the regional uncertainty and better climate change projections.
2018-01-01T00:00:00ZAssessing the Impacts of Climate Change on Streamflow in Malaba River Catchment, UgandaKangume, Charityhttp://repository.pauwes-cop.net/handle/1/392020-01-28T13:13:15Z2018-01-01T00:00:00ZAssessing the Impacts of Climate Change on Streamflow in Malaba River Catchment, Uganda
Kangume, Charity
Malaba River in Uganda a focal area to the Lake Kyoga basin is prone to climate change because of its heavy reliance on rainfall as its major flow contributor. The impacts of climate change on streamflow in Malaba River were assessed using LARS-WG downscaling model and Soil and Water Assessment Tool (SWAT) model. This was achieved by downscaling the future (2020-2050) precipitation and temperature variables for A1B and A2 scenarios and simulating the projected climate with calibrated LARS-WG and SWAT models for the two scenarios. The SWAT calibration (1992 - 1999) and validation (2000 - 2004) NSE results were respectively 0.55 and 0.35. Results indicated that the projected areal rainfall will increase by 0.34 mm per year for A1B which is averagely 1% less than the baseline period. Areal rainfall for A2 scenario will increase by 0.41 mm per year which is averagely 9% more than the baseline period. The Flow Duration Curve analyses indicated that the A2 scenario displayed higher flows for all the percentiles as compared to the baseline flows while A1B scenario has lower flows for percentiles less than 50, and equal or slightly higher flows for percentiles greater than 50 as compared to the baseline flows.
2018-01-01T00:00:00ZDrought Forecasting Under Climate Change Scenarios Using Artificial Neural Networks for Sustainable Water Resources Management in Upper Tana River Basin, KenyaMutua, Benedict Mwavuhttp://repository.pauwes-cop.net/handle/1/382020-01-28T13:13:15Z2018-01-01T00:00:00ZDrought Forecasting Under Climate Change Scenarios Using Artificial Neural Networks for Sustainable Water Resources Management in Upper Tana River Basin, Kenya
Mutua, Benedict Mwavu
Climate change has continued to impact negatively on water resources globally. For instance, extreme weather conditions especially the drought phenomena have become frequent in Africa. This has prompted water engineers and hydrologists to formulate mitigation and adaptation measures to address these challenges. The frequency of drought event of a defined severity for a defined return period is fundamental in planning, designing, operating and managing water resources systems within a basin. This paper presents an analysis of the hydrological drought frequency for the upper Tana River basin in Kenya using the absolute Stream flow Drought Index (SDI) and modified Gumbel technique. The study used a 41-year (1970-2010) stream flow data and forecasted hydrological droughts for 2, 5, 10, 20, 50, 100, 200, 500 and 1000-year return periods in relation to the selected stream flows. The results provide an overview of drought trends within the river basin and therefore would be very useful in applying drought adaptation policies by water resource managers.
2018-01-01T00:00:00ZClimate and Land-cover Change in Dryland-Catchments, and their Effect on Spate-hydrology of Farming Community in Semi-arid Lowlands of Raya-Valley, Northern EthiopiaNegash, Emnethttp://repository.pauwes-cop.net/handle/1/372020-01-28T13:13:15Z2018-01-01T00:00:00ZClimate and Land-cover Change in Dryland-Catchments, and their Effect on Spate-hydrology of Farming Community in Semi-arid Lowlands of Raya-Valley, Northern Ethiopia
Negash, Emnet
Spate-irrigation, a system foreseen as a potential means of improving agricultural production in rainfall deficit lowlands, is profoundly threatened by climate and land-cover change upstream. Yet, the actual implications of these changes on spate-hydrology has not been well studied. The objective of this study was thus to analyse the hydrological-response of dryland catchments to changing climate and land-cover in the Raya-valley. Longterm climate data were collected from National Meteorological Agency, and land-cover information extracted from Landsat satellite images. Soil Conservation Systems Curve-Number method was then employed to formulate the likely impacts of climate and land-cover dynamics on spate-hydrology. Average temperature, and evapotranspiration of the study area raised at a Coefficient of 0.13oC yr-1, and 16.43mm yr-1 respectively. Rainfall on the other hand dropped at a coefficient of 5.1mm yr-1. Land-cover change and Normalized Difference Vegetation Index analysis also showed improvement in vegetation-cover, enhancing water-retention capacity of the soil upstream. Declining rainfall, coupled with rising temperature and evapotranspiration on the top of increasing water-retention capacity of the soil aggravated moisture stress, thereby threatening spate-hydrology at a coefficient of 0.23x106m3 yr-1. Appropriate policies and strategies would therefore be desirable to address contesting interests on scarce water resources in the face of climate-change.
2018-01-01T00:00:00Z