The Observed Hydroclimate Variability and Changes in the Guder River Watershed, Blue Nile Basin

Diagenetic evolution and reservoir potential of the Barremian–Cenomanian Debre Libanose Sandstone, Blue Nile (Abay) Basin, Ethiopia

Paleoredox conditions of the Middle-Upper Jurassic black shales in the Blue Nile Basin, Ethiopia

In the Upper Blue Nile (UBN) basin, there is very sparse and uneven distribution of ground-based meteorological stations which constrain assessments on rainfall distributions and representation. To assess the diurnal cycle of rainfall across the UBN basin, satellite observations from Tropical Rainfall Measuring Mission (TRMM) were used in this study. Data of 7 years (2002–2008) of Precipitation Radar (PR) and TRMM Microwave Imager (TMI) were processed, with analyses based on geographic information system (GIS) operations, statistical techniques, and harmonic analysis. Diurnal cycle patterns of rainfall occurrence and rain rate from three in-situ weather stations are well represented by the satellite observations. Harmonic analysis depicts large differences in the mean of the diurnal cycle, amplitude, and time of the amplitude across the study area. Diurnal cycle of rainfall occurrence has a single peak in Lake Tana, Gilgel Abbay, and Jemma subbasins and double peaks in Belles, Dabus, and Muger subbasins. Maximum rain rate occurs in the morning (Gilgel Abbay, Dabus, and Jemma), afternoon (Belles, Beshilo, and Muger), and evening (Lake Tana and along the river gorges). Results of this study indicate that satellite observations provide an alternative source of data to characterize diurnal cycle of rainfall in data-scarce regions. We noticed, however, that there are a number of constraints to the use of satellite observations. For more accurate assessments, satellite products require validation by a network of well-distributed ground stations. Also, we advocate bias correction.

A framework for separating natural and anthropogenic contributions to evapotranspiration of human-managed land covers in watersheds based on machine learning

Assessment of soil loss and understanding its major drivers are essential to implement targeted management interventions. We have proposed and developed a Revised Universal Soil Loss Equation framework fully implemented in the Google Earth Engine cloud platform (RUSLE-GEE) for high spatial resolution (90 m) soil erosion assessment. Using RUSLE-GEE, we analyzed the soil loss rate for different erosion levels, land cover types, and slopes in the Blue Nile Basin. The results showed that the mean soil loss rate is 39.73, 57.98, and 6.40 t ha−1 yr−1 for the entire Blue Nile, Upper Blue Nile, and Lower Blue Nile Basins, respectively. Our results also indicated that soil protection measures should be implemented in approximately 27% of the Blue Nile Basin, as these areas face a moderate to high risk of erosion (>10 t ha−1 yr−1). In addition, downscaling the Tropical Rainfall Measuring Mission (TRMM) precipitation data from 25 km to 1 km spatial resolution significantly impacts rainfall erosivity and soil loss rate. In terms of soil erosion assessment, the study showed the rapid characterization of soil loss rates that could be used to prioritize erosion mitigation plans to support sustainable land resources and tackle land degradation in the Blue Nile Basin.

ABSTRACTIt is known that river basin is the most appropriate unit for planning, developing and managing water resources and for analysing water availability and water use. However, conflicting views of water resource utilization and ownership as well as sedimentation and flooding have challenged the development of appropriate management of the Nile River basin. The riparian states’, especially Egypt, Sudan and Ethiopia's, livelihood and energy source are solely dependent on the Nile River. Thus, effective and cooperative management of soil erosion/sedimentation in the upper Nile basin is increasingly important from an economic, social and environmental perspective. The Ethiopian government alone has implemented watershed management practices since 1980s which have not proved to be satisfactory. However, there is a lack of updated information concerning the Upper Nile River basin where many questions are raised from downstream and upstream states, communities and scholars. To fill this gap, the study included the following research questions: Is there updated published information about integrated river basin management (IRBM) concerning the Upper Blue Nile basin (BNB)? What effects brought the implementation of IRBM practices in the Upper BNB? What is the role of stakeholder's participation in the river basin management at various levels? How are institutions contributing for successful river basin management? Is there strong linkage between upstream and downstream countries so far? Thus to answer these questions, this review paper intends to provide comprehensive information about the IRBM impact in the upper BNB in Ethiopia. According to the study, the implemented in situ watershed management practices in the upper Blue Nile River had brought positive effects on sediment and flooding reduction as well as on improving water flow. Moreover, the upstream–downstream linkages and cooperation are essential for sustainable water resources management and equitable water share among the Nile riparian states. It was founded that strong institutions and stakeholder participation at all levels as well as appropriate policy could facilitate the river basin management implementation. It is concluded that a better understanding of the sustainable impact of river basin management in the headwaters of the BNB is of paramount importance because of the divergent interest in water resources access, and the ever-growing demand for energy and food in upstream and downstream countries. Thus, it is suggests that the negotiations of riparian states in the Nile basin should continue focusing on ‘benefit sharing’ and the win–win option.

Water-Energy-Food Nexus assessments at river basin scale make sense in particular if hydropower is an important source of energy in a given region. The Blue Nile Basin is a major source for Water in the Nile river basin. It provides around 65 % of the flow of the Nile entering Egypt, and occupies a mere 10% of the total basin area. The Blue Nile water is primarily used for irrigation, hydropower, and domestic supply in Ethiopia, Sudan, and Egypt. Climate variability and long-term climate and socio-economic changes pose a growing challenge to the provision of water, energy, and food security within the Blue Nile Basin as well as downstream. Thus, the scientifically sound quantification of available natural resources sustaining water, energy, and food security, and the development of different future scenarios can be helpful for decision-makers in the region. We suggest a new method of WEF Nexus accounting based on quantification of Nexus indicators derived mainly from public domain data. As observed data on water and land resources in the Blue Nile Basin are scarce, this study uses diverse remote sensing-based data sources to derive essential environmental information validated by using ground data, where possible. This includes land cover data, different precipitation products, actual evapotranspiration, net primary productivity (NPP), among others. Furthermore, several data analysis and modeling tools, such as WA+, various hydrological models, RiverWare, CropWat, etc., are employed to quantify the natural resources availability, variability, and productivity as a basis for a comprehensive WEF accounting based on selected indicators which were developed by a team of experts and scientists. The currently constructed Grand Ethiopian Renaissance Dam (GERD) as well as other planned hydropower and irrigation schemes are also considered for the future scenarios. The result is a comprehensive WEF Nexus accounting estimating water availability and uses with a focus on irrigation as the dominant water user, productivities (based on NPP and derived yield estimates), water use efficiency, energy production from hydropower and estimation of security levels compared to the required current and future demands. Finally, the derived nexus indicators are put into context of selected SDG target indicators.

Discovery of chitinoidellids and calpionellids from the Blue Nile Basin and the Jurassic-Cretaceous boundary in Ethiopia

Challenges and prospects of transboundary river water conservation and watershed protection in Ethiopia: The case of the upper Blue Nile

A review of hydroclimate variability and changes in the Blue Nile Basin, Ethiopia

Today, water resources of most countries are under unprecedented stress. Given the fast growth of the global population, a 40% shortage between water demand and supply is projected by the World Bank by 2030. Moreover, climate change, climatic extremes and chronic water scarcity are threatening global water security. To achieve sustainability and strengthen water security, countries are investing in water resources management tools that will enable them to make optimal decisions under increasing uncertainty.The Blue Nile Basin (BNB), Ethiopia contributes over 60% of the Nile flow, and its water management decisions deeply influence all of East Africa. Despite the fact that the BNB has the physical resources to drive regional economic growth through irrigated agriculture and hydropower development, its exceptional climate variability and sensitivity to climate change have limited this development.This lecture will discuss water resources management of the BNB in general with a more specific focus on the development of an integrated surface water-groundwater model of the Lake Tana region, the source of the Blue Nile, which can be used as a tool for optimal water resources management. Model simulations using both a physically-based and a data-driven model are discussed and compared. The challenges are multiple – starting from the scarcity of the available in-situ data that inspired the establishment of a citizen science initiative involving high school students, to creating an accurate conceptual model representation and parameterizing the model to match reality as close as possible.The work presented here is part of an NSF (National Science Foundation) funded PIRE (Partnerships for International Research and Education) project. This project is a multi-year collaborative endeavor that aims to craft state-of-the-art tools to enable smallholder farmers in the BNB make practical decisions about water, crops and fertilizers and ultimately gain more secure access to food and water in the face of increasingly challenging climatic extremes (http://pire.engr.uconn.edu).

The Upper Blue Nile basin is less explored in drought studies as compared to other river basins in Ethiopia and a shortage of particular basin drought monitoring system. The area founds in along a Blue Nile basin faced a recurrent drought conditions in several years ago. The main objectives of this study are to investigate droughts along a Blue Nile basin in the east Gojjam zone. To evaluate the drought duration, severity, occurrence and risks it was used different indices. The results show a hydrological drought was occurring in a frequent condition in partial areas of Shebel Berenta, Goncha siso enese and Enarg enawuga woreda. Based on 12-month time-scale, the total number of drought events were identified in the area, using Reconnaissance drought index (RDI) during the period of analysis (1995–1996) and its values 100% drought and its ranges were highly sever. Considering the drought events in the stream flow drought index (SDI) the values indicates drought severity was existed in the year 1984/1985 and 1989/1990. Inaddation standard precipitation index (SPI) also indicates a severity of drought in 1984/1985, 1990/1991 and 1991/1992 and its values was -1.5. Generally the hydrological, metrological and agricultural drought where existed in the year (1984-2012) within the study area.

Drought is one of the least understood and complex natural hazards often characterized by a significant decrease in water availability for a prolonged period. It can be manifested in one or more forms as meteorological, agricultural, hydrological, and/or socio-economic drought. The overarching objective of this study is to demonstrate and characterize the different forms of droughts and to assess the multidimensional nature of drought in the Abbay/ Upper Blue Nile River (UBN) basin and its national and regional scale implications. In this study, multiple drought indices derived from in situ and earth observation-based hydro-climatic variables were used. The meteorological drought was characterized using the Standardized Precipitation Index (SPI) computed from the earth observation-based gridded CHIRPS (Climate Hazards Group InfraRed Precipitation with Station) rainfall data. Agricultural and hydrological droughts were characterized by using the Soil Moisture Deficit Index (SMDI) and Standardized Runoff-discharge Index (SRI), respectively. The monthly time series of SMDI was derived from model-based gridded soil moisture and SRI from observed streamflow data from 1982 to 2019. The preliminary result illustrates the good performance of the drought indices in capturing the historic severe drought events (e.g., 1984 and 2002) and the spatial extents across the basin. The results further indicated that all forms of droughts (i.e., meteorological, agricultural, and hydrological) occurred concurrently in Abbay/Upper Blue Nile basin with a Pearson correlation coefficient ranges from 0.5 to 0.85 both Kiremt and annual aggregate periods. The concurrent nature of drought is leading to a multi-dimensional socio-economic crisis as indicated by rainfall, and soil moisture deficits, and drying of small streams. Multi-dimensional drought mitigation necessitates regional cooperation and watershed management to protect both the common water sources of the Abbay/Upper Blue Nile basin and the socio-economic activities of the society in the basin. This study also underlines the need for multi-scale drought monitoring and management practices in the basin.

The Abyssinian Plateau’s climate varies with latitude, altitude and exposure or slope. The rainy season is extended from June until September (Hurst et al., 1931). The West of Ethiopia receives higher amount of rainfall than the remainder of the country. Highland rainfall normally peaks in August in the administrative regions of Welo and Northern part of Shewa. Rains decreases over most of the highlands during September ( Henricksen, 1986 ).The maximum rainfall amount was extracted for regular years from the Jemma station and found to be 287 mm. On the other hand, the minimum amount of rainfall was acquired and found to be 164 mm for drought years. The effect of these amounts for overall the Blue Nile Basin on the life span of Grand Ethiopian Renaissance Reservoir ( GERR ) were studied before by Moussa et al.,2016 and 2017 with time duration of 24 hours.About 98 percent of the annual sediments are carried by the Nile during the flood season. Most of these sediments are eroded from the Blue Nile high lands (about 82%). Since the Grand Ethiopian Renaissance Dam (GERD) starts to store the flooding water and sediment during this year, then water and sediment that will be stored by this dam will be varied from regular to the drought years especially when rainfall amounts are distributed over different administrative regions of the Blue Nile Basin. The objective of this research is to determine water and sediment discharge of the Nile Basin with respect to the new regulation of rainfall that will fill the GERR. Volume of water and sediment for the Blue Nile basin were determined by using remote sensing techniques and by the aid of hydrological model, watershed storm hydrograph model (WASHMO), that was established by Andy Ward 1986. Hydrological parameters for 15 sub basin were extracted from digital elevation model (DEM) of Shuttle Topographic Radar Mission. Other parameters that concern rainfall, soil characteristics and land cover were collected from Atlas of the Blue Nile Basin (Yilma and Awulachew, 2009) and input in the model in order to determine sediment yield from the Blue Nile Watershed.

Assessment of environmentally sensitive areas to desertification in the Blue Nile Basin driven by the MEDALUS-GEE framework