Land use and climate change impacts on the hydrology of the upper Mara River Basin, Kenya: results of a modeling study to support better resource management
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Open Access
- 18 July 2011
- journal article
- Published by Copernicus GmbH in Hydrology and Earth System Sciences
- Vol. 15 (7), 2245-2258
- https://doi.org/10.5194/hess-15-2245-2011
Abstract
Some of the most valued natural and cultural landscapes on Earth lie in river basins that are poorly gauged and have incomplete historical climate and runoff records. The Mara River Basin of East Africa is such a basin. It hosts the internationally renowned Mara-Serengeti landscape as well as a rich mixture of indigenous cultures. The Mara River is the sole source of surface water to the landscape during the dry season and periods of drought. During recent years, the flow of the Mara River has become increasingly erratic, especially in the upper reaches, and resource managers are hampered by a lack of understanding of the relative influence of different sources of flow alteration. Uncertainties about the impacts of future climate change compound the challenges. We applied the Soil Water Assessment Tool (SWAT) to investigate the response of the headwater hydrology of the Mara River to scenarios of continued land use change and projected climate change. Under the data-scarce conditions of the basin, model performance was improved using satellite-based estimated rainfall data, which may also improve the usefulness of runoff models in other parts of East Africa. The results of the analysis indicate that any further conversion of forests to agriculture and grassland in the basin headwaters is likely to reduce dry season flows and increase peak flows, leading to greater water scarcity at critical times of the year and exacerbating erosion on hillslopes. Most climate change projections for the region call for modest and seasonally variable increases in precipitation (5–10 %) accompanied by increases in temperature (2.5–3.5 °C). Simulated runoff responses to climate change scenarios were non-linear and suggest the basin is highly vulnerable under low (−3 %) and high (+25 %) extremes of projected precipitation changes, but under median projections (+7 %) there is little impact on annual water yields or mean discharge. Modest increases in precipitation are partitioned largely to increased evapotranspiration. Overall, model results support the existing efforts of Mara water resource managers to protect headwater forests and indicate that additional emphasis should be placed on improving land management practices that enhance infiltration and aquifer recharge as part of a wider program of climate change adaptation.Keywords
This publication has 27 references indexed in Scilit:
- Projected Changes in Mean and Extreme Precipitation in Africa under Global Warming. Part II: East AfricaJournal of Climate, 2011
- Effects of land cover change on flood peak discharges and runoff volumes: model estimates for the Nyando River Basin, KenyaHydrological Processes, 2010
- SWAT model application and prediction uncertainty analysis in the Lake Tana Basin, EthiopiaHydrological Processes, 2009
- Using satellite‐based rainfall estimates for streamflow modelling: Bagmati BasinJournal of Flood Risk Management, 2008
- Modelling hydrology and water quality in the pre-alpine/alpine Thur watershed using SWATJournal of Hydrology, 2007
- Estimating rainfall and water balance over the Okavango River Basin for hydrological applicationsJournal of Hydrology, 2006
- Unbiased Recursive Partitioning: A Conditional Inference FrameworkJournal of Computational and Graphical Statistics, 2006
- Estimating Uncertain Flow and Transport Parameters Using a Sequential Uncertainty Fitting ProcedureVadose Zone Journal, 2004
- Hydrological response of a catchment to climate and land use changes in Tropical Africa: case study South Central EthiopiaJournal of Hydrology, 2003
- Effective and efficient global optimization for conceptual rainfall‐runoff modelsWater Resources Research, 1992