Aquifer overexploitation could significantly impact crop production in the United States because 60% of irrigation relies on groundwater. Groundwater depletion in the irrigated High Plains and California Central Valley accounts for ∼50% of groundwater depletion in the United States since 1900. A newly developed High Plains recharge map shows that high recharge in the northern High Plains results in sustainable pumpage, whereas lower recharge in the central and southern High Plains has resulted in focused depletion of 330 km3 of fossil groundwater, mostly recharged during the past 13,000 y. Depletion is highly localized with about a third of depletion occurring in 4% of the High Plains land area. Extrapolation of the current depletion rate suggests that 35% of the southern High Plains will be unable to support irrigation within the next 30 y. Reducing irrigation withdrawals could extend the lifespan of the aquifer but would not result in sustainable management of this fossil groundwater. The Central Valley is a more dynamic, engineered system, with north/south diversions of surface water since the 1950s contributing to ∼7× higher recharge. However, these diversions are regulated because of impacts on endangered species. A newly developed Central Valley Hydrologic Model shows that groundwater depletion since the 1960s, totaling 80 km3, occurs mostly in the south (Tulare Basin) and primarily during droughts. Increasing water storage through artificial recharge of excess surface water in aquifers by up to 3 km3 shows promise for coping with droughts and improving sustainability of groundwater resources in the Central Valley.

/pdf/groundwater-depletion-and-sustainability-of-irrigation-in-1uo10bmc98.pdf

Groundwater depletion and sustainability of irrigation in the US High Plains and Central Valley

Global water crisis and future food security in an era of climate change

In response to the growth of private sector involvement in water supply management globally, anti-privatization campaigns for a human right to water have emerged in recent years. Simultaneously, alter-globalization activists have promoted alternative water governance mod- els through North-South red-green alliances between organized labour, environmental groups, women's groups, and indigenous groups. In this paper, I explore these distinct (albeit over- lapping) responses to water privatization. I first present a generic conceptual model of market environmentalist reforms, and explore the contribution of this framework to debates over 'ne- oliberalizing nature'. This conceptual framework is applied to the case of anti-privatization activism to elucidate the limitations of the human right to water as a conceptual counterpoint to privatization, and as an activist strategy. In contrast, I argue that alter-globalization strategies— centred on concepts of the commons—are more conceptually coherent, and also more successful as activist strategies. The paper concludes with a reiteration of the need for greater conceptual precision in our analyses of neoliberalization, for both academics and activists.

/pdf/the-commons-versus-the-commodity-alter-globalization-anti-2isrhe1pw6.pdf

The “Commons” Versus the “Commodity”: Alter‐globalization, Anti‐privatization and the Human Right to Water in the Global South

Improving agricultural water productivity: Between optimism and caution

https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1018&context=cee_facpub

Hydro-economic models: concepts, design, applications, and future prospects.

Climate change, water supply limits, and continued population growth have intensified the search for measures to conserve water in irrigated agriculture, the world's largest water user. Policy measures that encourage adoption of water-conserving irrigation technologies are widely believed to make more water available for cities and the environment. However, little integrated analysis has been conducted to test this hypothesis. This article presents results of an integrated basin-scale analysis linking biophysical, hydrologic, agronomic, economic, policy, and institutional dimensions of the Upper Rio Grande Basin of North America. It analyzes a series of water conservation policies for their effect on water used in irrigation and on water conserved. In contrast to widely-held beliefs, our results show that water conservation subsidies are unlikely to reduce water use under conditions that occur in many river basins. Adoption of more efficient irrigation technologies reduces valuable return flows and limits aquifer recharge. Policies aimed at reducing water applications can actually increase water depletions. Achieving real water savings requires designing institutional, technical, and accounting measures that accurately track and economically reward reduced water depletions. Conservation programs that target reduced water diversions or applications provide no guarantee of saving water.

https://www.pnas.org/content/pnas/105/47/18215.full.pdf

Water conservation in irrigation can increase water use

Contents: Introduction 1. Support for Environmental Policy Decisions 2. History and Scope of TCM 3. Demand Theory and TCM 4. Benefits Theory and TCM 5. Design Principles for TCMs 6. Design and Administration of Surveys 7. Measurement of the Variables 8. Data Management and Analysis 9. Developing and Maintaining Expertise Conclusion

Valuing Nature With Travel Cost Models: A Manual

The economic value of water in agriculture: concepts and policy applications $

The book presents a self-contained treatment of TCM along with a wide range of applications to natural resource and environmental policy questions.

Valuing Nature with Travel Cost Models

Estimates of the benefits of environmental improvement, usually a nonmarket commodity, can be a valuable part of the information base for economically efficient environmental decision making. The objective of this paper is to review the literature of one class of nonmarket valuation methodologies based on observed consumption behavior subsumed under the term "travel cost demand models." Relative to travel cost demand models, we examine policy issues and underlying concepts focusing on choice theory and welfare evaluation. In addition, we identify major related empirical issues including demand specification, data problems, demand estimation, and welfare measurement. Unanswered questions may contribute to a research agenda.

Frank A. Ward

Papers

Water conservation in irrigation can increase water use

Valuing Nature With Travel Cost Models: A Manual

The economic value of water in agriculture: concepts and policy applications $

Valuing Nature with Travel Cost Models

The Travel Cost Demand Model as an Environmental Policy Assessment Tool: A Review of Literature