Your search found 4 records
1 Kiptala, J. K.; Mohamed, Y.; Mul, Marloes L.; Cheema, M. J. M.; Van der Zaag, P. 2013. Land use and land cover classification using phenological variability from MODIS vegetation in the Upper Pangani River Basin, eastern Africa. Physics and Chemistry of the Earth, 66:112-122. [doi: https://doi.org/10.1016/j.pce.2013.08.002]
Land use ; Land cover ; Mapping ; Land classification ; Land suitability ; Phenology ; Vegetation ; River basins ; Water resources ; International waters ; Rain ; Remote sensing ; Irrigated farming ; Rainfed farming ; Calibration / Eastern Africa / Tanzania / Kenya / Upper Pangani River Basin
(Location: IWMI HQ Call no: e-copy only Record No: H046232)
(3.30 MB)
In arid and semi-arid areas, evaporation fluxes are the largest component of the hydrological cycle, with runoff coefficient rarely exceeding 10%. These fluxes are a function of land use and land management and as such an essential component for integrated water resources management. Spatially distributed land use and land cover (LULC) maps distinguishing not only natural land cover but also management practices such as irrigation are therefore essential for comprehensive water management analysis in a river basin. Through remote sensing, LULC can be classified using its unique phenological variability observed over time. For this purpose, sixteen LULC types have been classified in the Upper Pangani River Basin (the headwaters of the Pangani River Basin in Tanzania) using MODIS vegetation satellite data. Ninety-four images based on 8 day temporal and 250 m spatial resolutions were analyzed for the hydrological years 2009 and 2010. Unsupervised and supervised clustering techniques were utilized to identify various LULC types with aid of ground information on crop calendar and the land features of the river basin. Ground truthing data were obtained during two rainfall seasons to assess the classification accuracy. The results showed an overall classification accuracy of 85%, with the producer’s accuracy of 83% and user’s accuracy of 86% for confidence level of 98% in the analysis. The overall Kappa coefficient of 0.85 also showed good agreement between the LULC and the ground data. The land suitability classification based on FAO-SYS framework for the various LULC types were also consistent with the derived classification results. The existing local database on total smallholder irrigation development and sugarcane cultivation (large scale irrigation) showed a 74% and 95% variation respectively to the LULC classification and showed fairly good geographical distribution. The LULC information provides an essential boundary condition for establishing the water use and management of green and blue water resources in the water stress Pangani River Basin.
2 Kiptala, J. K.; Mohamed, Y.; Mul, Marloes L.; Van der Zaag, P. 2013. Mapping evapotranspiration trends using MODIS and SEBAL model in a data scarce and heterogeneous landscape in eastern Africa. Water Resources Research, 49(12):8495-8510. [doi: https://doi.org/10.1002/2013WR014240, 2013]
Mapping ; Evapotranspiration ; Evaporation ; Models ; Algorithms ; Data ; Semiarid climate ; Landscape ; Water use ; Water balance ; Water accounting ; River basins ; Land use ; Land cover ; Reservoirs ; Precipitation / Eastern Africa / Upper Pangani River Basin / Nyumba ya Mungu reservoir
(Location: IWMI HQ Call no: e-copy only Record No: H046302)
[1] Evapotranspiration (ET) accounts for a substantial amount of the water use in river basins particular in the tropics and arid regions. However, accurate estimation still remains a challenge especially in large spatially heterogeneous and data scarce areas including the Upper Pangani River Basin in Eastern Africa. Using multitemporal Moderate-resolution Imaging Spectroradiometer (MODIS) and Surface Energy Balance Algorithm of Land (SEBAL) model, 138 images were analyzed at 250 m, 8 day scales to estimate actual ET for 16 land use types for the period 2008–2010. A good agreement was attained for the SEBAL results from various validations. For open water evaporation, the estimated ET for Nyumba ya Mungu (NyM) reservoir showed a good correlations (R = 0.95; R2 = 0.91; Mean Absolute Error (MAE) and Root Means Square Error (RMSE) of less than 5%) to pan evaporation using an optimized pan coefficient of 0.81. An absolute relative error of 2% was also achieved from the mean annual water balance estimates of the reservoir. The estimated ET for various agricultural land uses indicated a consistent pattern with the seasonal variability of the crop coefficient (Kc) based on Penman-Monteith equation. In addition, ET estimates for the mountainous areas has been significantly suppressed at the higher elevations (above 2300 m a.s.l.), which is consistent with the decrease in potential evaporation. The calculated surface outflow (Qs) through a water balance analysis resulted in a bias of 12% to the observed discharge at the outlet of the river basin. The bias was within 13% uncertainty range at 95% confidence interval for Qs. SEBAL ET estimates were also compared with global ET from MODIS 16 algorithm (R = 0.74; R2 = 0.32; RMSE of 34% and MAE of 28%) and comparatively significant in variance at 95% confidence level. The interseasonal and intraseasonal ET fluxes derived have shown the level of water use for various land use types under different climate conditions. The evaporative water use in the river basin accounted for 94% to the annual precipitation for the period of study. The results have a potential for use in hydrological analysis and water accounting.
3 Kiptala, J. K.; Mul, Marloes L.; Mohamed, Y.; van der Zaag, P. 2014. Modelling stream flow and quantifying blue water using a modified STREAM model for a heterogeneous, highly utilized and data-scarce river basin in Africa. Hydrology and Earth System Sciences, 18:2287-2303. [doi: https://doi.org/10.5194/hess-18-2287-2014]
River basins ; Flow discharge ; Hydrology ; Models ; Water management ; Water resources ; Irrigation water ; Water use ; Remote sensing ; Evaporation ; Evapotranspiration ; Land use ; Soil moisture / Africa / Tanzania / Pangani River Basin
(Location: IWMI HQ Call no: e-copy only Record No: H046490)
http://www.hydrol-earth-syst-sci.net/18/2287/2014/hess-18-2287-2014.pdf
https://vlibrary.iwmi.org/pdf/H046490.pdf
https://vlibrary.iwmi.org/pdf/H046490.pdf
(1.06 MB) (1.26 MB)
Integrated water resources management is a combination of managing blue and green water resources. Often the main focus is on the blue water resources, as information on spatially distributed evaporative water use is not as readily available as the link to river flows. Physically based, spatially distributed models are often used to generate this kind of information. These models require enormous amounts of data, which can result in equifinality, making them less suitable for scenario analyses. Furthermore, hydrological models often focus on natural processes and fail to account for anthropogenic influences. This study presents a spatially distributed hydrological model that has been developed for a heterogeneous, highly utilized and data-scarce river basin in eastern Africa. Using an innovative approach, remote-sensingderived evapotranspiration and soil moisture variables for 3 years were incorporated as input data into the Spatial Tools for River basin Environmental Analysis and Management (STREAM) model. To cater for the extensive irrigation water application, an additional blue water component (Qb) was incorporated in the STREAM model to quantify irrigation water use. To enhance model parameter identification and calibration, three hydrological landscapes (wetlands, hillslope and snowmelt) were identified using field data. The model was calibrated against discharge data from five gauging stations and showed good performance, especially in the simulation of low flows, where the Nash–Sutcliffe Efficiency of the natural logarithm (Ens_ln) of discharge were greater than 0.6 in both calibration and validation periods. At the outlet, the Ens_ln coefficient was even higher (0.90). During low flows, Qb consumed nearly 50% of the river flow in the basin. The Qb model result for irrigation was comparable to the field-based net irrigation estimates, with less than 20% difference. These results show the great potential of developing spatially distributed models that can account for supplementary water use. Such information is important for water resources planning and management in heavily utilized catchment areas. Model flexibility offers the opportunity for continuous model improvement when more data become available.
4 Hassaballah, K.; Mohamed, Y.; Omer, A.; Uhlenbrook, Stefan. 2020. Modelling the inundation and morphology of the seasonally flooded Mayas Wetlands in the Dinder National Park-Sudan. Environmental Processes, 7(3):723-747. [doi: https://doi.org/10.1007/s40710-020-00444-5]
Wetlands ; Floodplains ; Flooding ; Hydrodynamics ; Modelling ; Hydrological factors ; Morphology ; Water levels ; Sediment ; Erosion ; Canals ; Rivers ; National parks ; Ecosystems / Sudan / Dinder River / Dinder National Park / Mayas Wetlands
(Location: IWMI HQ Call no: e-copy only Record No: H049807)
https://link.springer.com/content/pdf/10.1007/s40710-020-00444-5.pdf
https://vlibrary.iwmi.org/pdf/H049807.pdf
https://vlibrary.iwmi.org/pdf/H049807.pdf
(2.83 MB) (2.83 MB)
Understanding the spatiotemporal dynamics of surface water in varied, remote and inaccessible isolated floodplain lakes is difficult. Seasonal inundation patterns of these isolated lakes can be misestimated in a hydrodynamic model due to the short time of connectivity. The seasonal and annual variability of the Dinder River flow has great impact on what is so called Mayas wetlands, and hence, on the habitats and the ecological status of the Dinder National Park. This variability produces large morphological changes due to sediment transported within the river or from the upper catchment, which affects inflows to Mayas wetlands and floodplain inundation in general. In this paper, we investigated the morphological dimension using a quasi-3D modelling approach to support the management of the valuable Mayas wetlands ecosystems, and in particular, assessment of hydrological and morphological regime of the Dinder River as well as the Musa Maya. Six scenarios were developed and tested. The first three scenarios consider three different hydrologic conditions of average, wet and dry years under the existing system with the constructed connection canal. While the other three scenarios consider the same hydrologic conditions but under the natural system without an artificial connection canal. The modelling helps to understand the effect of human intervention (connection canal) on the Musa Maya. The comparison between the simulated scenarios concludes that the hydrodynamics and sedimentology of the Maya are driven by the two main factors: a) the hydrological variability of Dinder River; and b) deposited sediment plugs in the connection canal.
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