A critical discussion of recent studies that analysed the effects of climate change on the water resources of the River Nile Basin (RNB) is presented. First, current water-related issues on the RNB ...showing the particular vulnerability to environmental changes of this large territory are described. Second, observed trends in hydrological data (such as temperature, precipitation, river discharge) as described in the recent literature are presented. Third, recent modelling exercises to quantify the effects of climate changes on the RNB are critically analysed. The many sources of uncertainty affecting the entire modelling chain, including climate modelling, spatial and temporal downscaling, hydrological modelling and impact assessment are also discussed. In particular, two contrasting issues are discussed: the need to better recognize and characterize the uncertainty of climate change impacts on the hydrology of the RNB, and the necessity to effectively support decision-makers and propose suitable adaptation strategies and measures. The principles of a code of good practice in climate change impact studies based on the explicit handling of various sources of uncertainty are outlined.Citation Di Baldassarre, G., Elshamy, M., van Griensven, A., Soliman, E., Kigobe, M., Ndomba, P., Mutemi, J., Mutua, F., Moges, S., Xuan, J.-Q., Solomatine, D. & Uhlenbrook, S. (2011) Future hydrology and climate in the River Nile basin: a review. Hydrol. Sci. J.56(2), 199–211.
Soil moisture is a key water cycle parameter known to interact with atmospheric processes. Arguably, land surface models that simulate land surface processes and surface fluxes to the atmosphere do ...not capture adequately the spatial variability of soil moisture, particularly over areas with complex topography. In this study, version 3.5 of the Community Land Model (CLM3.5) is applied with a new parameterization in an effort to correct the spatial bias of soil moisture and understand the consequential effects on the simulated water cycle fluxes and states in the Blue Nile Basin. This parameterization accounts for a groundwater recharge term from surface water, a process that is not included in CLM, providing an effective two‐way interaction scheme between rivers and groundwater. Using satellite soil moisture data, this parameterized term is shown to have a positive correlation to contributing area, defined at each model grid cell and representing the number of grid cells that drain to that local grid cell. With the new parameterization applied to CLM, soil moisture, soil temperature, evapotranspiration flux, water table depth, and vegetation water content all showed significant differences from the control CLM run (without the parameterization) at or above the 95% confidence level. The differences in the spatial distribution of these variables are expected to affect precipitation simulations from regional climate modeling. As the Blue Nile is a region that has one of the greatest interannual and seasonal precipitation variability globally, the ability to predict this variability is essential for optimal reservoir operations including buffering of water resources during times of drought.
Key Points
Highlighted the need for applying a ground water recharge parameterization
New parameterization improved surface soil moisture simulations
New parameterization affected all simulated water cycle parameters
The planning and implementation of effective water resources management strategies need an assessment of multiple (physical, environmental, and socio-economic) issues, and often requires new research ...in which knowledge of diverse disciplines are combined in a unified methodological and operational framework. Such integrative research to link different knowledge domains faces several practical challenges. The complexities are further compounded by multiple actors frequently with conflicting interests and multiple uncertainties about the consequences of potential management decisions.
This thesis aims to overcome some of these challenges, and to demonstrate how new modeling approaches can provide successful integrative water resources research. It focuses on the development of new integrated modeling approaches which allow integration of not only physical processes but also socio-economic and environmental issues and uncertainties inherent in water resources systems. To achieve this goal, two new approaches are developed in this thesis.
At first, a Bayesian network (BN)-based decision support tool is developed to conceptualize hydrological and socio-economic interaction for supporting management decisions of coupled groundwater-agricultural systems. The method demonstrates the value of combining different commonly used integrated modeling approaches. Coupled component models are applied to simulate the nonlinearity and feedbacks of strongly interacting groundwater-agricultural hydrosystems. Afterwards, a BN is used to integrate the coupled component model results with empirical knowledge and stakeholder inputs.
In the second part of this thesis, a fuzzy-stochastic multiple criteria decision analysis tool is developed to systematically quantify both probabilistic and fuzzy uncertainties associated with complex hydrosystems management. It integrates physical process-based models, fuzzy logic, expert involvement and stochastic simulation within a general framework.
Subsequently, the proposed new approaches are applied to a water-scarce coastal arid region water management problem in northern Oman, where saltwater intrusion into a coastal aquifer due to excessive groundwater extraction for irrigated agriculture has affected the aquifer sustainability, endangering associated socio-economic conditions as well as traditional social structures.
The results show the effectiveness of the proposed methods. The first method can aid in the impact assessment of alternative management interventions on sustainability of aquifer systems while accounting for economic (agriculture) and societal interests (employment in agricultural sector) in the study area. Results from the second method have provided key decision alternatives which can serve as a platform for negotiation and further exploration. In addition, this approach suits to systematically quantify both probabilistic and fuzzy uncertainties associated with the decision problem. The new approaches can be applied to address the complexities and uncertainties inherent in water resource systems to support management decisions, while serving as a platform for stakeholder participation.
The Blue Nile Basin, Ethiopia, whose inter-annual variability in local precipitation has resulted in droughts and floods that lead to economic and food insecurity, is the area of interest for our ...NSF-PIRE project, which aims to develop novel forecast technologies to mitigate the stresses to local communities. As part of the PIRE project, a Citizen Science Initiative (PIRE CSI) was established in June 2017, a project that trains high school students in hydrologic data collection under the guidance of classroom teachers and graduate students and professors from Bahir Dar University in four watersheds of interest, located south of Lake Tana, Ethiopia. Four MSc graduate students were selected from Bahir Dar University and trained nine high school students who were nominated taking into account gender and the proximity of their schools to the watersheds. High school students are currently collecting soil moisture data using TDR, river stage measurements using optical levels and groundwater levels using shallow water level meters. The data collection is supported by an app (B-WING), developed specifically for the needs of the project. College-ready activities are being planned for the high school students, i.e. inviting them to Bahir Dar University to analyze some of the data, present their work at a workshop, and familiarize themselves with the university experience. Recently, the PIRE CSI was extended to involve local farmers as “citizen scientists”, collecting soil moisture data using low-cost, soil moisture sensors developed in-house at the University of Connecticut, that have been installed in 12 locations and two soil depths (20 cm and 40 cm). The collected data will be used for the initialization and validation of the hydrological models developed in the region. The PIRE CSI promotes the empowerment of local communities and establishes long-lasting partnerships between scientists and stakeholders. It is believed that the co-generation of knowledge may contribute to higher rates of forecast adaption by the local farmers and may trigger the student’s interest in STEM and encourage their uptake of scientific careers. Acknowledgment: This material is based upon work supported by the National Science Foundation under Grant No. 1545874.
Provider: Czech digital library/Česká digitální knihovna - Institution: Academy of Sciences Library/Knihovna Akademie věd ČR - Data provided by Europeana Collections- Recently water resources ...reanalysis (WRR) global streamflow products are emerging from high- resolution global models as a means to provide long and consistent global streamflow products for assessment of global challenge such as climate change. Like any other products, the newly developed global streamflow products have limitations accurately represent the dynamics of local streamflow hydrographs. There is a need to locally evaluate and apply correction factors for better representation and make use of the data. This research focuses on the evaluation and correction of the bias embedded in the global streamflow product (WRR, 0.25°) developed by WaterGAP3 hydrological model in the upper Blue Nile basin part of Ethiopia. Three spatiotemporal dynamical bias correction schemes (temporalspatial variable, temporal-spatial constant and spatial variable) tested in twelve watersheds of the basin. The temporalspatial variable dynamical bias correction scheme significantly improves the streamflow estimation. The Nash-Sutcliffe coefficient (NSCE) improves by 30% and bias decreases by 19% for the twelve streamflow gauging stations applying leave one out cross-validation approach in turn. Therefore, the temporal-spatial variable scheme is applicable and can use as one method for the bias correction to use the global data for local applications in the upper Blue Nile basin.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
PDF
