Your search found 3 records
1 Benon, Z. T.; McCartney, Matthew. 2008. Evaluation of the water budgets of the equatorial lakes of the White Nile. Paper presented at the International Nile Basin Development Forum, Khartoum, Sudan, 3-5 November 2008. 15p.
River basin management ; Lakes ; Ecosystems ; Water budget ; Simulation models ; Hydrology ; Water balance ; Rainfall-runoff relationships ; Evaporation / Uganda / Congo / Upper Nile Basin / White Nile Basin / Lake Victoria / Lake Albert / Lake Kyoga / Lake Edward / Lake George
(Location: IWMI HQ Call no: e-copy only Record No: H041834)
(0.27 MB)
2 Collick, A. S.; Easton, Z. M.; Ashagrie, T.; Biruk, B.; Tilahun, S.; Adgo, E.; Awulachew, Seleshi Bekele; Zeleke, G.; Steenhuis, T. S. 2009. A simple semi-distributed water balance model for the Ethiopian highlands. Hydrological Processes, 23:3718-3727. [doi: https://doi.org/10.1002/hyp.7517]
Rainfall-runoff relationships ; Soil water ; Water balance ; Models ; Calibration ; Hydrology ; River basins ; Watersheds ; Climate / Ethiopia / Sudan / Egypt / Nile Basin / Upper Nile Basin / Yeku Watershed
(Location: IWMI HQ Call no: e-copy only Record No: H042577)
(0.31 MB)
The discharge of the Nile River is highly dependent on the flow generated in the highlands of Ethiopia. However, little is known about the local (i.e. small scale) watershed hydrological response, due in part to a lack of long duration, continuous hydrological data. The goal of this paper was to develop a realistic, simple model that is useful as a tool for planning watershed management and conservation activities so that the effects of local interventions on stream flow can be predicted at a larger scale. The developed model is semi-distributed in that it divides the watershed into different regions that become hydrologically active given different amounts of effective cumulative rainfall after the start of the rainy season. A separate water balance is run for each of the hydrologic regions using rainfall and potential evaporation as the major inputs. Watershed parameters that were calibrated included the amount of water required before each region becomes hydrologically active, the fraction of soil water that becomes runoff and subsurface flow, and aquifer characteristics, Model validation indicated that daily discharge values were predicted reasonably well with Nash Sutcliffe values ranging from 0Ð56 to 0Ð78. Despite the large distance between the test watersheds, the input parameter values for the watershed characteristic were remarkably similar for the humid highlands, indicating that the model could be used to predict discharge in un-gauged basins in the region. As expected, the watershed in the semi-arid region behaved somewhat differently than the other three watersheds. Good quality precipitation data, even for short durations, were key to the effective modelling of runoff in the highland watersheds.
3 Nanteza, J.; de Linage, C. R.; Thomas, B. F.; Famiglietti, J. S. 2016. Monitoring groundwater storage changes in complex basement aquifers: an evaluation of the GRACE satellites over East Africa. Water Resources Research, 52(12):9542-9564. [doi: https://doi.org/10.1002/2016WR018846.]
Groundwater ; Water storage ; Monitoring ; Aquifers ; Satellite observation ; Surface water ; Soil moisture ; Water balance ; Models ; Lakes ; Wells ; Water use ; Hydroclimatology ; Climate change ; Precipitation ; Rain ; Estimation / East Africa / Kenya / Uganda / Tanzania / Burundi / Rwanda / Upper Nile Basin / Lake Victoria / Lake Tanganyika / Lake Malawi / Lake Turkana / Lake Albert / Lake Mweru / Lake Edward
(Location: IWMI HQ Call no: e-copy only Record No: H048049)
(3.24 MB)
Although the use of the Gravity Recovery and Climate Experiment (GRACE) satellites to monitor groundwater storage changes has become commonplace, our evaluation suggests that careful processing of the GRACE data is necessary to extract a representative signal especially in regions with significant surface water storage (i.e., lakes/reservoirs). In our study, we use cautiously processed data sets, including GRACE, lake altimetry, and model soil moisture, to reduce scaling factor bias and compare GRACE-derived groundwater storage changes to in situ groundwater observations over parts of East Africa. Over the period 2007–2010, a strong correlation between in situ groundwater storage changes and GRACE groundwater estimates (Spearman's = 0.6) is found. Piecewise trend analyses for the GRACE groundwater estimates reveal significant negative storage changes that are attributed to groundwater use and climate variability. Further analysis comparing groundwater and satellite precipitation data sets permits identification of regional groundwater characterization. For example, our results identify potentially permeable and/or shallow groundwater systems underlying Tanzania and deep and/or less permeable groundwater systems underlying the Upper Nile basin. Regional groundwater behaviors in the semiarid regions of Northern Kenya are attributed to hydraulic connections to recharge zones outside the subbasin boundary. Our results prove the utility of applying GRACE in monitoring groundwater resources in hydrologically complex regions that are undersampled and where policies limit data accessibility.
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