This volume provides a critical focus on the need to plan for a range of climate conditions for some of the world’s most vulnerable populations, with special attention to arid and semi-arid regions, and a political science approach to understanding water governance. Geographic coverage includes the Jordan River Basin, Amu Darya, Nile, Mekong, the Colorado, Tagus, and Fergana Valley.

Drought is a naturally occurring phenomenon in each. Similarly, water scarcity—whether caused by decreasing rain, increasing temperatures, or conscious management decisions—is also a historically recurrent feature. Its effects are far-reaching, from decreased ecological function to humanitarian crises. Societies have devised structures and political arrangements to deliver water, and the ultimate test of these structures is how well they hold up during a shortage. The volume’s editors assert in the introduction and conclusion that climate change, combined with population growth, will continue to strain water resources in transboundary basins. Appropriately addressing these phenomena requires going beyond legal approaches to include economic, technological, political, and incentive-based mechanisms. The contributors discuss how to implement these practices and how to draw stakeholder countries into the decision-making process.

The volume is organized in three parts. Part I builds an overall understanding of the economic, institutional, and technological aspects of transboundary basins. The authors introduce the concept of a baseline requirement of a per capita minimum volume and its relevance for planning. How we think about this baseline requirement has changed over time. In the first chapter, Yacov Tsur argues that because there are more people on the planet, the water requirement thresholds have dropped from a 1989 “water stress” definition of 1700 cubic meters per person/year to a 1996 definition of “subsistence scarcity” of 100 cubic meters per person/year. Tsur presents forecasts of sustainable supply (the amount that can be used without depleting freshwater reserves) based on UN estimates of population growth, suggesting that by 2030 the natural water supply is likely to fall below 100 cubic meters per person/year. Environmental flows have been caught in the middle of increasing water prices and decreasing crop values, setting up the urgent need to restore natural flows both for human and ecosystem well-being.

The two chapters in Part II cover legal agreements between states, focusing on the borders between United States and Mexico and between Israel and Palestine. The authors suggest that water banking and transfers may be an alternative in places where treaties are not possible, and they argue that establishing general peace agreements regarding borders may be a prerequisite to water negotiations.

Border delineation can have a chain of governance effects, establishing a basis of diversification for single-source households and irrigators, offering them basic access to drinking water and small farm irrigation when wells and springs are dry. The cases offer a strikingly candid assessment of the difficulties of achieving a treaty between countries in over-allocated basins. Political scientists will be familiar with the difficulties caused by common pool resources, hegemony, and conflict. The basic laws of geography are ever-present, especially when it comes to hydroshed location and positioning along a river and elevation gradient.

Part III covers management arrangements, valuation approaches, and efforts to estimate the economic benefits of alternatives for restoration. The chapters blend considerations of efficiency in water storage and social trade-offs of the delivery infrastructure. One lesson is that, as dams become larger, it is important to consider whether the net gains are worth the costs. The ability to calculate the value of these gains and losses is invaluable for the social planner. When appropriately paired with natural basin features, dams can efficiently deliver water where it is needed. When allocations are balanced according to the weights associated with their intended outcomes (namely large-scale agricultural irrigation and hydropower), the end result can be multilateral cooperation around more than water. At this point, the reader will likely be prompted to return to the thorough econometric case study of the eastern Nile River Basin in Part I to see how this optimization could occur in practice.

Getachew Nigatu and Ariel Dinar see trading water as akin to trading products and services. They use multiple alternative water rights arrangements (WRA) and joint pairing of basin pricing and trades to model net gains for countries in the Nile River Basin through the principle of comparative advantage. For example, if Ethiopia were to focus on hydropower generation and sell excess energy to the other countries, then Egypt would focus on irrigated agriculture, a sector that is relatively efficient. At the same time, they consider how their economic and environmental optimization model (with agriculture and hydropower as the focal demands) fits with the ongoing efforts of the Nile Basin Initiative to build cooperation around preventing resource degradation, addressing water scarcity, and achieving food security.

Water banking allows for nonmarket valuation of environmental flows and ecological restoration if institutions are set up to address basin-wide priorities and design strategic plans to achieve multiple-use objectives. WRA models are designed to accommodate a range of preferences, interactions, and objectives across multiple uses: agricultural, municipal/industrial, and hydropower generation. Recognizing that tradeoffs must be made, different allocation methods can be used. These include “priority” (where, for each step, the network flow solver attempts to satisfy the water users with the highest priority first), and “objective function” (where each component, benefit, or user is given equal weight). In Chapter 10, Nir Becker and David Katz discuss restorative flows and recreational uses of the Jordan River, including original survey-based research on tourists’ willingness to pay for increased flows and enhanced water quality. They find that all three populations—Jordanians, Israelis, and Palestinians—would benefit from restoration in multiple scenarios.

In sum, this volume provides a variety of solutions and range of regional coverage that stakeholders are likely to find practical. While integrated water resources management may be the gold standard in basin planning, the authors offer a realistic assessment of the tools that can be leveraged in cases where comprehensive planning is unraveled by political pressures. For example, downstream states with weaker negotiating positions can improve their leverage by linking issues like regional trade with upstream countries. The key takeaway for the international relations theorist is that as water becomes scarce, conflict may ensue. With this concern in mind, the contributors present concepts, echniques and models that can facilitate cooperation between countries and sectors.