Urban growth in areas across the United States and rising demand for environmental goods and services place increased pressure on limited water resources. Much of the U.S. has experienced higher temperatures, increased variability in precipitation, and prolonged droughts in recent decades, and climate models forecast these trends to continue into the future (Wuebbles et al. 2017). Annual trends toward earlier spring melt and reduced snowpack in the western U.S. and depletion of major aquifers increase water management challenges. It is no surprise to see a recent policy statement of the American Meteorological Society observe that, “the provision of adequate fresh-water resources for people and ecosystems will be one of the most critical and potentially contentious issues facing society and governments at all levels during the 21^st century (American Meteorological Society 2017).”

New approaches are needed to resolve the water management challenges. The goal of these new approaches should be to efficiently use available water, and to minimize damage to human communities and the ecosystems on which they depend from flood, drought, and impaired water quality. General strategies to achieve these goals are to increase conservation and reallocate water more efficiently among competing uses, by using technologies and creating institutions that encourage efficient water use. These strategies require improved understanding of the complex relationships between water resource and human systems, how individuals and groups of individuals evaluate trade-offs and respond to incentives, and assessment of the physical and economic impacts associated with alternative technologies and institutions.

This application is for the renewal of the multistate committee W3190, whose members are well-equipped to conduct research and propose solutions to water management challenges. Current and past members of W3190 and its earlier iterations have a long history of collaborative research and engagement on water management issues. Recent examples from W3190 include analysis of water marketing as a way to extend water availability (Ghosh et al. 2014; Hansen et al. 2015); integrated models of hydrology and economics to better capture the relationship between bio-physical processes and socio-economic factors (Guilfoos et al. 2016; Hrozencik et al. 2016; Maas et al. (2016); and analysis of alternative groundwater management strategies, for example extraction limits, over portions of the Ogallala Aquifer (Keeler et al. 2018; Silva et al. 2018).The research proposed below for the new multistate committee W4190 addresses a variety of water management issues, with the overarching goal of increasing society’s net benefit from limited water availability. Multistate committee W4190’s suite of research questions and methods will document relationships between water resource and human systems, and test the feasibility and economic efficiency of innovative water management practices, policies, and institutions.

One challenge of water management and related research is that relationships between water resource and human systems vary considerably across space and time. Solutions developed for one location must be adapted to fit climatic, economic, and social conditions in another location; a successful solution must also often be adapted over time as conditions in a particular location change, too. Further, advances in measurement technology, computing power, and research methods from a variety of physical and social sciences increase the tools at our disposal for addressing and resolving conflict and expand our potential to better understand, evaluate, and improve on existing water management strategies. This W4190 proposal consequently includes new themes, which reflect emerging challenges facing water managers and recent methodological innovations.

First, this proposal contains an increased emphasis on documenting interlinkages between water resource and human systems. Water resource and human systems are impacted by changes in climate and/or other anthropogenic disturbances. Changes occurring at both global and local/regional scales include: changes in vegetation and land use/land cover attributable to both climatic and anthropogenic factors (Nicholls et al. 2007); shifts in seasonal climate patterns that might be overlooked in local or regional climate assessments (Gitau 2016), and, changes in occurrences and severity of extreme events (Collins et al. 2013). Extreme events are particularly concerning as these pose the greatest challenges with respect to associated impacts on water resource and human systems (Zhang et al. 2011; Klein-Tank et al. 2009). It is impossible to evaluate alternative technologies and policies effectively without a robust understanding of these interlinkages and impacts.

Second is a greater emphasis on the connections and interactions between water scarcity and water quality. Intensive agriculture and input use are on the rise, placing pressure on water availability and quality in many locations. For example, many coastal as well as inland aquifers are affected by saltwater intrusion when aquifer levels decline (Barlow and Reichard 2010). Best management practices (BMPs) are often able to improve water quality and conserve water quantity in tandem (Meierdiercks et al. 2017). Improved conjunctive management of surface and groundwater may also conserve water quantity and improve water quality. Alternative water sources (for example stormwater and wastewater use in irrigation (McNabb 2017)) may relieve pressure altogether on existing sources. Policymakers increasingly request information on these relationships to help them address water scarcity and improve water quality.

A third and final recurring theme throughout this proposal is the increased application of methods from behavioral and experimental economics to water management questions. This committee has historically been heavily populated with economists whose primary area of focus has been evaluation of trade-offs, individual decision-making, and the structuring of incentives to encourage efficient allocation of water resources. What behavioral and experimental economics contribute to this continued focus is the recognition that individuals and groups of individuals do not always behave rationally, or in accordance with a textbook model of profit-maximization (Kahneman and Tversky 1979; Thaler 1980). A number of the projects described below allow for the possibility that less water would be used and at lower cost through use of alternative structures, for example peer benchmarking, rather than economic incentives.

The changing composition of this multistate committee over the years reflects the dynamic nature of water resource challenges in the U.S. Research undertaken through the committee was originally focused on improving water allocation and management under conditions of scarcity prevalent in the western U.S. Over the past ten years, however, researchers in the historically water-rich eastern U.S. have joined the group, as stakeholders and policymakers in these areas begin to grapple with water scarcity and quality groundwater availability. This transition in membership has contributed to the shift, described above, from near-exclusive focus on water scarcity to a broader recognition of the importance of water quality to water resource and human systems.

Stakeholders. The committee’s core stakeholders are state and federal policymakers, water managers, and practitioners. Many of the projects described below are motivated by requests for information and analysis made of W3190 members by stakeholders, and undertaken with the explicit goal of providing local and regional water managers and policymakers with tools that will strengthen the resiliency of their stakeholder communities and improve their ability to manage water resources in the face of long-term drought and climate uncertainty. The research will often be undertaken collaboratively with extension personnel, local conservation district, or other agency staff. At the conclusion of the research, W4190 members will develop and deliver outreach presentations and publications for stakeholders that distill research findings into practical, science-based management tools and policy recommendations. These tools will empower stakeholders to objectively dissect complex water issues and correctly weigh benefits and costs of alternative options.

Importance of the Work. The research proposed for W4190 is often undertaken in response to stakeholder requests for information and analysis. Not by coincidence, it also addresses national and regional priorities for water management. The USGS Committee on Water Science and Research recently commissioned a study from the National Academy of Sciences (NAS) to identify the highest priority water resource and science challenges for the U.S. over the next 25 years. The NAS report, compiled based in part on input from USGS stakeholders (federal, state, tribal, and local agencies, private companies, and individuals) identifies ten research questions, five of which relate directly to the research proposed for W4190 below: 1) How do human activities affect water quantity and quality; 2) How does changing climate affect water quality, quantity, and reliability, as well as water-related hazards and extreme events; 3) How can long-term water-related risk management be improved; 4) How do institutions and governance and institutional resilience impact the quantity and quality of water; and 5) How can competing uses for water resources be managed and maintained to sustain healthy communities and ecosystems in a changing world. These research questions are at the heart of the W4190 proposal.

Advantages of Multistate Collaboration on Water Management. Research and outreach on water management lend themselves naturally to multistate collaborations first and foremost because rivers and groundwater aquifers do not respect state boundaries. Policymakers from adjacent states regularly work together to manage shared water resources; water resource researchers similarly collaborate across state boundaries to address shared water management challenges. The collaborative relationships facilitated by W3190 also improve the flow of information and ideas across state boundaries. Tools implemented successfully in one location can rarely be applied entirely to other locations without some adaptation to local circumstances, but inspiration for management approaches and institutions can often be found by examining what has worked well in other locations. This cross-fertilization and testing of new ideas also improves stakeholder engagement and facilitates transmission of knowledge from one generation of researchers to the next through mentorship of junior members.

Technical Feasibility of the Proposed Research. The proposed research has a high degree of technical feasibility. Our multistate team includes water professionals with rigorous training in conceptual, theoretical, and applied aspects of bio-physical sciences and water resource economics. Team members also have extensive experience analyzing water management practices, policies, and institutions. Current membership of W3190 includes 55 researchers from 26 states (half of which are located east of the 100^th meridian, a region which has not had severe water quantity concerns in the past), USDA-ARS, USDA/FS, and USDC-NOAA; we anticipate many current W3190 members will sign up for W4190. Agricultural and natural resource economists comprise the largest portion of the team, followed by soil scientists. Solutions to water management challenges are often inherently interdisciplinary. We enthusiastically welcome colleagues from irrigation engineering, agronomy, and hydrology and water quality, as well as other social sciences besides economics.

Impacts of Improved Water Management. Without innovation in water management policies and approaches, water-related conflicts between states, water sources (ground versus surface), water uses (for example agricultural, urban, and environmental) and users will continue to intensify and expand. The tools developed and analyzed in the proposed research will help stakeholders to objectively dissect complex water issues and correctly weigh benefits and costs of alternative options. If implemented, policy recommendations will stretch limited water resources further at lower cost and with reduced negative impacts on the environment and other water users. Policy recommendations will help resolve conflicts between water users and makes communities more resilient to climate change and prolonged drought.