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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The spatial and temporal variability of the hydro-climate as well as land use and land cover (LULC) changes are among the most challenging problems facing water resources management. Understanding the interaction between climate variability, land use and land cover changes and their links to hydrology, river morphology and ecohydrology in the Dinder and Rahad basins in Sudan is confronted by the lack of climatic, hydrological and ecological data. This book investigated the impacts of land degradation on the Dinder and Rahad hydrology and morphology, and interlinkage to the ecohydrological system of the Dinder National Park (DNP) in Sudan. It used an ensemble of techniques to improve our understanding of the hydrological processes and LULC changes in these basins. This included long-term trend analysis of hydroclimatic variables, LULC changes analysis, field measurements, rainfall-runoff modelling, hydrodynamic and morphological modelling of the Dinder river and its floodplain, with special focus on the Mayas wetlands. Moreover, this research is the first study to investigate the eco-hydrology of the DNP. It is expected that the results of the study will be beneficial to all stakeholders concerned and support decision-making processes for better management of water resources and ecosystem conservation in the area and possibly beyond.@en

This paper examines the long-term trends of streamflow, rainfall and temperature over the Dinder and Rahad River basins. Streamflow of the Rahad River showed significant increasing trends in both the annual and seasonal flows. There was no detectable change in the mean annual and seasonal flow patterns of the Dinder. However, the analysis of seasonal maxima suggested a shift towards decreased flows during the high flow period (August) and increased flows during the low flow period (November). The Dinder maxima of August decreased from 517 m³/s over the early part of the record (1972–1991) to 396 m³/s over the latest years (1992–2011). The mean annual temperature showed significant increasing trends at the rate of 0.24 and 0.30°C/decade in the examined stations. Rainfall showed no significant change. The result of this study suggests other factors than climate variability (e.g., land use and land cover changes) to be responsible for streamflow alterations.

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Understanding the land use and land cover changes (LULCCs) and their implication on surface hydrology of the Dinder and Rahad basins (D&R, approximately 77 504 km2) is vital for the management and utilization of water resources in the basins. Although there are many studies on LULCC in the Blue Nile Basin, specific studies on LULCC in the D&R are still missing. Hence, its impact on streamflow is unknown. The objective of this paper is to understand the LULCC in the Dinder and Rahad and its implications on streamflow response using satellite data and hydrological modelling. The hydrological model has been derived by different sets of land use and land cover maps from 1972, 1986, 1998 and 2011. Catchment topography, land cover and soil maps are derived from satellite images and serve to estimate model parameters. Results of LULCC detection between 1972 and 2011 indicate a significant decrease in woodland and an increase in cropland. Woodland decreased from 42 to 14 % and from 35 to 14 % for Dinder and Rahad, respectively. Cropland increased from 14 to 47 % and from 18 to 68 % in Dinder and Rahad, respectively. The model results indicate that streamflow is affected by LULCC in both the Dinder and the Rahad rivers. The effect of LULCC on streamflow is significant during 1986 and 2011. This could be attributed to the severe drought during the mid-1980s and the recent large expansion in cropland.

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