Developing a preliminary recharge model of the Nile Basin to help interpret GRACE data

GRACE data provides a new and exciting opportunity to gain a direct and independent measure of water mass variation on a regional scale, but the data must be combined with hydrological modelling to indicate in which part of the water cycle the mass change has occurred. Processing GRACE data through a series of spectral filters indicates a seasonal variation to gravity mass (±0.005 mGal) thought to relate to the downstream movement of water in the catchment, and delayed storage from groundwater, following the wet season in the upper catchment. To help interpret these data a groundwater recharge model was developed for the Nile Catchment using the model ZOODRM (a distributed modelling code for calculating spatial and temporal variations in groundwater recharge). ZOODRM was an appropriate model to use for this work, due to the lower data demands of the model, relative to other groundwater models, the ability of the model to use entirely remotely-sensed input data, and the added functionality of runoff routing. Rainfall (NOAA data) and ET data were sourced from the FEWS NET African Data Dissemination Service. Geological data was sourced from the digital geology map of the world, landuse data from the USGS and the DEM data from ESRI. Initial model results indicate groundwater recharge across the basin of 0-4mma-1, with obvious considerable spatial variability. The results indicate the importance of groundwater in storing rainfall, and releasing it slowly throughout the year in different parts of the catchment. Only by modelling this process can GRACE data be reliably interpreted hydrologically. Despite only a qualitative interpretation of the GRACE data having been achieved within this preliminary study, the work has indicated that the ZOODRM model can be used with entirely remotely-sensed data, and that sufficient data exists for the Nile Basin to construct a plausible recharge model. Future work is now required to properly calibrate the model to enable closer comparison of the Nile GRACE data

Nile Basin Focal Project. Synthesis report

The Nile basin experiences wide spread poverty, lack of food and land and water degradation. Because poverty is linked to access to water for crop, fish and livestock based livelihoods, improving access to water and increasing agricultural water productivity can potentially contribute substantially to poverty reduction. The major goal of the Nile Basin Focal project is to identify high potential investments that reduce poverty yet reverse trends in land and water degradation. This is done through the implementation of six interlinked work packages allowing us to examine water availability, access, use, productivity, institutions and their linkages to poverty. Important in the Nile BFP is knowledge management and the uptake of results for ultimate impact

Water resources management in the Nile basin: The economic value of cooperation

Water Policy73227-252WPAO

Estimation of ungauged Bahr el Jebel flows based on upstream water levels and large scale spatial rainfall data

The study derives Bahr el Jebel flow data at Mongalla, combining upstream flow from Lake Albert and torrential runoff derived from the Collaborative Historical African Rainfall Model (CHARM) rainfall data in the catchment between Lake Albert and Mongalla using GIS techniques. The results provide an updated rating curve for Lake Albert outflows and currently unavailable flow data at Mongalla, the entry to the Sudd swamp, with a high level of confidence for the period after 1983; data which are essential for detailed hydrological assessments of the swamp system with its significant importance for the economies and lives of people in the area

A synthesis of past, current and future research for protection and management of papyrus (Cyperus papyrus L.) wetlands in Africa

Papyrus wetlands (dominated by the giant sedge Cyperus papyrus L.) occur throughout eastern, central and southern Africa and are important for biodiversity, for water quality and quantity regulation and for the livelihoods of millions of people. To draw attention to the importance of papyrus wetlands, a special session entitled ‘‘The ecology of livelihoods in papyrus wetlands’’ was organized at the 9th INTECOL Wetlands Conference in Orlando, Florida in June 2012. Papers from the session, combined with additional contributions, were collected in a special issue of Wetlands Ecology and Management. The current paper reviews ecological and hydrological characteristics of papyrus wetlands, summarizes their ecosystem services and sustainable use, provides an overview of papyrus research to date, and looks at policy development for papyrus wetlands. Based on this review, the paper provides a synthesis of research and policy priorities for papyrus wetlands and introduces the contributions in the special issue. Main conclusions are that (1) there is a need for better estimates of the area covered by papyrus wetlands. Limited evidence suggests that the loss of papyrus wetlands is rapid in some areas; (2) there is a need for a better understanding and modelling of the regulating services of papyrus wetlands to support trade-off analysis and improve economic valuation; (3) research on papyrus wetlands should include assessment of all ecosystem services (provisioning, regulating, habitat, cultural) so that trade-offs can be determined as the basis for sustainable management strategies (‘wise use’); (4) more research on the governance, institutional and socio-economic aspects of papyrus wetlands is needed to assist African governments in dealing with the challenges of conserving wetlands in the face of growing food security needs and climate change. The papers in the special issue address a number of these issues

Geological and environmental resources investigations in Egypt using LANDSAT images

There are no author-identified significant results in this report

International Water Rights on the White Nile of the New State of South Sudan

The birth of South Sudan falls directly in the demarcation zone of the rivalry between downstream and upstream riparian states on the waters of the Nile River. The downstream states—Egypt and Sudan—stress their “natural and historic” rights to the entire flow of the Nile based on the 1959 Nile Agreement and older colonial treaties, while the upstream African states refuse to be bound by colonial treaties and claim their equitable share of the Nile River by promoting South Sudan’s accession to the Cooperative Framework Agreement (CFA). The Nile River Basin lacks an international binding water agreement that includes and satisfies all the riparian states. This Article analyzes the status quo of South Sudan’s water rights to the Nile River by addressing the following questions: Is the new state bound by any rights and obligations established by the 1959 Nile Agreement? Is it advantageous for South Sudan to accede to the CFA, which provides for modern principles of international water law? The Article applies the customary international law of state succession to South Sudan’s secession from Sudan to determine if the 1959 Nile Agreement is binding between the two states. It concludes that South Sudan succeeded Sudan with regard to territorial rights and obligations established by the 1959 Nile Agreement, as customary international law recognizes that legal obligations of a territorial nature remain unaffected by state succession. South Sudan should enter into negotiations on a binding water agreement to allocate the 18.5 billion cubic meters of water granted to it under the 1959 Nile Agreement. The Article concludes that South Sudan should accede to the CFA within its allotted portion of the Nile waters under the 1959 Nile Agreement

A sensitivity study on the role of the swamps of southern Sudan in the summer climate of North Africa using a regional climate model

We used the regional climate model RegCM3 to investigate the role of the swamps of southern Sudan in affecting the climate of the surrounding region. Towards this end, we first assessed the performance of a high resolution version of the model over northern Africa. RegCM3 shows a good skill in simulating the climatology of rainfall and temperature patterns as well as the related circulation features during the summer season, outperforming previous coarser resolution applications of the model over this region. Sensitivity experiments reveal that, relative to bare soil conditions, the swamps act to locally modify the surface energy budget primarily through an increase of surface latent heat flux. Existence of the swamps leads to lower ground temperature (up to 2 °C), a larger north–south temperature gradient, and increased local rainfall (up to 40 %). Of particular importance is the impact on rainfall in the surrounding regions. The swamps have almost no impact on the rainfall over the source region of the Nile in Ethiopia or in the Sahel region; however, they favor wetter conditions over central Sudan (up to 15 %) in comparison to the bare desert soil conditions.Abdus Salam International Centre for Theoretical Physics (Earth System Physics)International Atomic Energy AgencySTEP progra

Water-use accounts in CPWF basins: Simple water-use accounting of the Nile Basin

This paper applies the principles of water-use accounts, developed in the first of the series, to the Nile River basin in Northeast Africa. The Nile and its tributaries flow though nine countries. The White Nile flows though Uganda, Sudan, and Egypt. The Blue Nile starts in Ethiopia. Zaire, Kenya, Tanzanian, Rwanda, and Burundi all have tributaries, which flow into the Nile or into Lake Victoria. Unique features are Lake Victoria and the Sudd wetland where White Nile loses about half of its flow by evaporation, and the Aswan Dam which controls flow in the lower part of the Basin and also is where 15-20% of the flow is lost to seepage and further evaporation. Net runoff is minimal in many catchments of the Nile Basin, comprising 6% or less of the water available in 16 catchments of the Basin. In the remaining catchments, net runoff ranges from 9% (Panyango) to 34% (Gambella) of the available water. Water use by grassland is important in all catchments where it comprises 13 to 76% of the water available, except in the Lower Basin, where it comprises only 7% or less of the available water. In upstream catchments, woodlands and forests are the major components of land-use, while in the Lower Basin catchments barren and sparsely vegetated land is the main land-use class. Rainfed agriculture is the most important water use by volume in only four catchments, Kessie, Paraa, Panyango, and the Sennar Dam where it comprises 24%, 27%, 30%, and 38% of the available water. Nevertheless, it is a relatively important use of water in many of the catchments, using 10% or more of the available water in 14 catchments of the Basin. Irrigated agriculture is the least use of water by volume, using 4% or less of the available water in all catchments except the d/s of Jebel Aulia, the Sennar Dam, Thamaniyat, Hudeiba, Atbara, Naga Hammadi, El Ekhsase, and Estuary catchments. It is, however, the most important water use in the Estuary catchment, using 90% of the available water. The effect of climate change on rainfall in the Nile Basin is very uncertain, but temperature is expected increase by about 2°C by mid-century. To show the possible effects, we increased potential evapotranspiration by 5%, and left rainfall unchanged. The flow at Aswan Dam declines by about 6%, and irrigated crop water use in the El- Ekhsase region increases by about 2%. Keywords: Water use accounts, Nile basin, top-down modelling, basin water us