Kevin Wheeler

When construction of the Grand Ethiopian Renaissance Dam (GERD) is completed, the Nile will have two of the world’s largest dams—the High Aswan Dam (HAD) and the GERD—in two different countries (Egypt and Ethiopia). There is not yet agreement on how these dams will operate to manage scarce water resources. We elucidate the potential risks and opportunities to Egypt, Sudan and Ethiopia by simulating the filling period of the reservoir; a new normal period after the reservoir fills; and a severe multi-year drought after the filling. Our analysis illustrates how during filling the HAD reservoir could fall to levels not seen in recent decades, although the risk of water shortage in Egypt is relatively low. The new normal will benefit Ethiopia and Sudan without significantly affecting water users in Egypt. Management of multi-year droughts will require careful coordination if risks of harmful impacts are to be minimized.

Due to limited data and scarce financial resources in developing regions, policy decisions for managing water resources must often be made without a full understanding of what potential impacts on water quality may result. This study demonstrates a methodology for utilizing georeferenced statistical data to assess the primary pollution contributions and to model the physical impacts resulting from these contributions. Using socio-economic data on population, agricultural production and industrial output provides a basis for evaluating the potential effects on the current water quality situation and allows a method to assess the influences resulting from changes of these socio-economic patterns. This study focused on evaluating the current conditions in the Yellow River in China. A conceptual model is developed to estimate Biochemical Oxygen Demand (BOD) generation and link these sources with the hydrologic characteristics of the landscape to generate BOD loadings into the main river...

The Grand Ethiopian Renaissance Dam (GERD) on the Nile River will double Ethiopia’s electricity generation and reduce the Nile flow to Sudan and Egypt during reservoir filling. We argue that multi-country negotiations over the initial filling and long-term operation of the GERD reservoir should not overlook key dam engineering features.

Colorado River managers face many uncertainties—issues like climate change, future water demand, and evolving ecological priorities—and are looking for new tools to help cope with this uncertain future. They need new ways to help classify uncertain conditions, manage for uncertain conditions, and to create models in the face of a slew of oncoming unknowns. To help Colorado River stakeholders think about, talk about, and better manage the future river, the Center for Colorado River Studies offers a new white paper that distinguishes four levels of decision-making uncertainty and suggest tools and resources to manage the different levels

<p>This study analyzes the implications of a variety of filling approaches of the Grand Ethiopian Renaissance Dam (GERD) for the outlet management and dam engineering. A daily water balance model of the GERD is developed and used to investigate the ability of the GERD outlets to enable six reservoir filling scenarios. Results show that the turbines’ outlets, the bottom outlets, and the spillways would sufficiently provide downstream releases during the steady-state operation of the GERD. The river diversion outlets of the GERD are necessary to enable agreements on reservoir filling and the Ethiopian turbine phasing-in plan. The use of the river diversion outlets requires compliance with dam engineering constraints such as steel lining, head limit, and maximum flow speed. We propose a multi-objective optimization framework for reservoir filling whereby dam engineering constraints are considered in the negotiations on the initial filling of multi-year storage reservoirs.</p>

As the Grand Ethiopian Renaissance Dam (GERD) nears completion, the Nile River Basin is at a crossroads. The next few months will be consequential for relations between countries in the river basin—notably Ethiopia, Sudan, and Egypt—because dam management upstream could have consequences for the supply of water downstream. Although the three countries began discussions after the project was announced in 2011, they have yet to reach an agreement on how the new reservoir should be filled and managed. Despite the absence of an agreement, Ethiopia intends to begin filling the reservoir this July. This article examines the competing perspectives between countries, explains reasons for the lack of an agreement, and provides recommendations for addressing the challenges of the GERD.

The ongoing debate over the management, protection, and restoration of the Colorado River Delta near the U.S.-Mexico border can be informed by quantifying the effects of restoring flows to the Delta. The once-vibrant Colorado River Delta was nearly decimated by the construction of dams and diversions in the United States and Mexico. However, flood management, inadvertent releases from upstream reservoirs, and agricultural return flows partially restored the Delta in the 1980s and 1990s. Recent research estimates the Delta's freshwater needs to sustain native riparian forests and associated wetlands-at 50,000 acre-feet annually (commonly referred to as baseflows), plus occasional flood flows (one in four years) of at least 260,000 acre-feet in May and June. If this need were to be regularly met, what would be the impact on existing water uses? This article documents a collaborative study to examine various alternative scenarios for delivering the estimated minimum freshwater flow...

The Ili-Balkhash basin (IBB) is considered a key region for agricultural development and international transport as part of China’s Belt and Road Initiative (BRI). The IBB is exemplary for the combined challenge of climate change and shifts in water supply and demand in transboundary Central Asian closed basins. To quantify future vulnerability of the IBB to these changes, we employ a scenario-neutral bottom-up approach with a coupled hydrological-water resource modelling set-up on the RiverWare modelling platform. This study focuses on reliability of environmental flows under historical hydro-climatic variability, future hydro-climatic change and upstream water demand development. The results suggest that the IBB is historically vulnerable to environmental shortages, and any increase in water consumption will increase frequency and intensity of shortages. Increases in precipitation and temperature improve reliability of flows downstream, along with water demand reductions upstream ...

The ongoing debate over the management, protection, and restoration of the Colorado River Delta near the U.S.-Mexico border can be informed by quantifying the effects of restoring flows to the Delta. The once-vibrant Colorado River Delta was nearly decimated by the construction of dams and diversions in the United States and Mexico. However, flood management, inadvertent releases from upstream reservoirs, and agricultural return flows partially restored the Delta in the 1980s and 1990s. Recent research estimates the Delta's freshwater needs to sustain native riparian forests and associated wetlands-at 50,000 acre-feet annually (commonly referred to as baseflows), plus occasional flood flows (one in four years) of at least 260,000 acre-feet in May and June. If this need were to be regularly met, what would be the impact on existing water uses? This article documents a collaborative study to examine various alternative scenarios for delivering the estimated minimum freshwater flow...

We analyse the threats of global environmental change, as they relate to food security. First, we review three discourses: (i) 'sustainable intensification', or the increase of food supplies without compromising food producing inputs, such as soils and water; (ii) the 'nexus' that seeks to understand links across food, energy, environment and water systems; and (iii) 'resilience thinking' that focuses on how to ensure the critical capacities of food, energy and water systems are maintained in the presence of uncertainties and threats. Second, we build on these discourses to present the causal, risks and options assessment for decision-making process to improve decision-making in the presence of risks. The process provides a structured, but flexible, approach that moves from problem diagnosis to better risk-based decision-making and outcomes by responding to causal risks within and across food, energy, environment and water systems.

The ongoing debate over the management, protection, and restoration of the Colorado River Delta near the U.S.-Mexico border can be informed by quantifying the effects of restoring flows to the Delta. The once-vibrant Colorado River Delta was nearly decimated by the construction of dams and diversions in the United States and Mexico. However, flood management, inadvertent releases from upstream reservoirs, and agricultural return flows partially restored the Delta in the 1980s and 1990s. Recent research estimates the Delta’s freshwater needs—to sustain native riparian forests and associated wetlands—at 50,000 acre-feet annually (commonly referred to as baseflows), plus occasional flood flows (one in four years) of at least 260,000 acre-feet in May and June. If this need were to be regularly met, what would be the impact on existing water uses? This article documents a collaborative study to examine various alternative scenarios for delivering the estimated minimum freshwater flows needed to sustain the Delta ecosystems. Using the Bureau of Reclamation’s Colorado River Simulation System (CRSS) model, this paper presents the hydrologic differences of several alternative assured sources of baseflows and flood flows, including system water releases, market-based mechanisms, and various combinations of the two. In addition, we considered one alternative that does not fully meet the minimum requirements during shortage conditions (defined by a low elevation of water in Lake Mead). Alternatives were studied specifically to determine their effects on Colorado River water storage and deliveries, with particular attention to changes in water available to current consumptive users. On one extreme, making additional system water releases for the Delta from Lake Mead would reduce expected deliveries in Arizona by 2.7 percent, in Nevada by 1.7 percent, and in California by 0.2 percent by the year 2060. In contrast, leasing water from existing uses for the Delta could have a slightly beneficial effect on other existing uses in the United States. This article does not seek to advocate one particular alternative over another, but to provide an understanding of the impacts of these alternatives.