Addressing Impediments and Incentives for Agricultural Reuse

Water Research Foundation | December 6th, 2023

Water systems across the United States are facing unprecedented levels of stress arising from challenges such as a changing climate, aging infrastructure, and shifting pa

Water systems across the United States are facing unprecedented levels of stress arising from challenges such as a changing climate, aging infrastructure, and shifting patterns of water supply and demand. Agricultural water reuse has the potential to increase the resilience of water and agricultural systems through benefits such as supply diversification, access to an additional water supply, nutrient management, and compliance with water quality permits. However, realization of these benefits and scaling reuse are hindered by broad ranging, but surmountable barriers and tradeoffs. Part 1 of this report (Literature Review) provides a synthesis of the health and agronomic risks of agricultural water reuse in the context of current regulatory frameworks. Part 2 of this report (Guidebook) highlights specific strategies for addressing barriers to agricultural water reuse and includes thirteen profiles of projects and programs advancing agricultural water reuse. This work (WRF 4956) directly builds on the lessons learned in WRF 4775, Agricultural Use of Recycled Water: Impediments and Incentives, (Sheikh et al. 2019) and WRF 4829, Economic and Environmental Benefits of Agricultural Water Reuse (Thebo 2021). While the specific drivers and challenges of agricultural water reuse projects vary widely across contexts, several common themes emerged in this work. The most successful agricultural water reuse projects invariably address multiple objectives and deliver co-benefits to diverse stakeholders. They do this through early, ongoing, and strategic stakeholder engagement and partnerships. State and federal agencies can support advancement of agricultural water reuse through robust capacity building programs and integration of co-benefits into funding programs. Science-based regulatory programs that are aligned with the needs of both water agencies and the agricultural sector can streamline permitting processes while remaining protective of human, agronomic, and environmental health. In combination, the research products developed in WRF 4956 aim to support water managers, regulators, and the agricultural sector in identifying and overcoming barriers to agricultural water reuse across diverse geographic and agricultural contexts in the United States.

Addressing Institutional Vulnerabilities in California’s Drought Water Allocation, Part 1: Water Rights Administration and Oversight During Major Statewide Droughts, 1976–2016

California Natural Resources Agency (CNRA) | August 30th, 2018

Climate change has already begun to affect California’s hydrology and water resources, and droughts are likely to become more frequent, longer, and more intense

Climate change has already begun to affect California’s hydrology and water resources, and droughts are likely to become more frequent, longer, and more intense in the future (see Section 2.2.4). This project is designed to help state water governance and decision-making structures adapt to this changing climatic reality. We focus on how one of California’s primary water management institutions, the State Water Resources Control Board (Board), has responded in the past, and could better respond in the future, to droughts and their attendant challenges, including water shortage, uncertainty, and conflict. Click here for Part 2.

Addressing Institutional Vulnerabilities in California’s Drought Water Allocation, Part 2: Improving Water Rights Administration and Oversight for Future Droughts

California Natural Resources Agency (CNRA) | August 30th, 2018

 In California, droughts are likely to become more frequent, longer, and more intense in the future, posing increasing challenges for water management, and raising the s

 In California, droughts are likely to become more frequent, longer, and more intense in the future, posing increasing challenges for water management, and raising the stakes for effective drought response. This project aims to help state water governance and decision-making structures adapt to the changing climatic reality. In a companion report in this volume, we analyzed the strategies the State Water Resources Control Board (Board) used for water rights administration and oversight during the last four major statewide droughts. Our findings suggest that more proactive planning and preparation, enabling reduced reliance on in-drought improvisation, would improve the Board’s future drought responses. This report builds on that retrospective analysis with specific recommendations.  Click here for Part 1.

Addressing Multiple Stressors and Multiple Goals in the Delta Plan

Delta Stewardship Council (Delta Council) | January 26th, 2011

Addressing Nitrate in California’s Drinking Water Technical Report 1: Project and Technical Report Outline

University of California, Davis (UC Davis) | July 2nd, 2012

Addressing Nitrate in California’s Drinking Water Technical Report 2: Nitrogen Sources and Loading to Groundwater

University of California, Davis (UC Davis) | July 2nd, 2012

Nitrate loading to groundwater in the Tulare Lake Basin and Salinas Valley is widespread and chronic, and is overwhelmingly the result of crop and animal agricultural ac

Nitrate loading to groundwater in the Tulare Lake Basin and Salinas Valley is widespread and chronic, and is overwhelmingly the result of crop and animal agricultural activities. Urban wastewater, septic systems, and other sources may have significant localized impact. Due to long transit times, the impact on groundwater resources is a legacy for years and decades to come.

Addressing Nitrate in California’s Drinking Water Technical Report 3: Nitrogen Source Reduction to Protect Groundwater Quality

University of California, Davis (UC Davis) | July 2nd, 2012

Although reduction of anthropogenic loading of nitrate to groundwater aquifers will not reduce contamination in the short term (due to long travel times), reduction effo

Although reduction of anthropogenic loading of nitrate to groundwater aquifers will not reduce contamination in the short term (due to long travel times), reduction efforts are a critical component of any long term solution to the problem of high nitrate in drinking water. Technologies are available for reducing the transfer of nitrate to groundwater from surface sources. Such technologies involve (1) reducing the amount of nitrogen (N) discharged or applied to the land and (2) controlling the amount of water applied to land which serves as the carrier of nitrate. Many of these source control methods require changes in land management and upgrading of infrastructure.

Addressing Nitrate in California’s Drinking Water Technical Report 4: Groundwater Nitrate Occurrence

University of California, Davis (UC Davis) | July 2nd, 2012

This report reviews the hydrogeology and groundwater quality in the Tulare Lake Basin (TLB) and Salinas Valley (SV). We also assembled groundwater quality data from near

This report reviews the hydrogeology and groundwater quality in the Tulare Lake Basin (TLB) and Salinas Valley (SV). We also assembled groundwater quality data from nearly two dozen local, state, and federal agencies and other sources into a dataset, here referred to as the (Central) California Ambient Spatio-Temporal Information on Nitrate in Groundwater (CASTING) dataset. The dataset combines nitrate concentrations from 16,709 individual samples taken at 1,890 wells in the Salinas Valley (SV) and from 83,375 individual samples taken at 17,205 wells in the Tulare Lake Basin (TLB) collected from the 1940s to 2011, accounting for a total of 100,084 samples from 19,095 wells. Almost 70% of these samples were collected from 2000 to 2010; only 15% of the samples were collected prior to 1990. Half of all wells sampled had no recorded samples prior to 2000.

Addressing Nitrate in California’s Drinking Water Technical Report 5

University of California, Davis (UC Davis) | July 31st, 2012

This report explores methods and costs of remediation of groundwater nitrate contamination in the Tulare Lake Basin and Salinas Valley. Groundwater cleanup, or remediati

This report explores methods and costs of remediation of groundwater nitrate contamination in the Tulare Lake Basin and Salinas Valley. Groundwater cleanup, or remediation, is one of the most difficult actions in the environmental sciences, even when done on the scale of a small contaminant plume (1000s of cubic meters). Remediation of entire groundwater basins has never been attempted at the scale and depths of the Salinas Valley and Tulare Lake Basin, on the order of billions of cubic meters. This analysis shows that direct remediation to remove nitrate from large groundwater basins is extremely costly and not technically feasible. In situ remediation, though technologically infeasible as a regional remedy, is appropriate in certain areas of shallow groundwater with high contaminant levels. Traditional pump and treat (ex situ) methods are too slow to produce results on the regional scale in an acceptable time frame, prohibitively expensive, and impractical to implement. A novel form of pump-and-treat remediation is possible in the study area, but not yet widely practiced. By monitoring the nitrogen content of pumped irrigation water, and taking that ambient nutrient source into account when calculating additive fertilizer amounts, farmers can reduce the amount of nitrogen input to the aquifer. Such an approach is not unlike phytoremediation and is herein called “pump-and fertilize.” Pump-and-fertilize is part of an effective nutrient management program. Due to the nature of irrigation with groundwater, it is as much a source reduction method as it is a form of groundwater remediation. Hot spot and pump-and-fertilize remediation alone will not solve the problem of groundwater nitrate contamination. A new approach is needed that combines regional groundwater and nitrogen management strategies. This approach would include monitoring, source reduction, maximization of clean groundwater recharge across agricultural landscapes, pump-and-fertilize, and in situ treatment targeted at shallow, high-concentration plumes to place regional water quality on a trajectory toward improvement. Modeling and monitoring of regional groundwater quality are integral to an effective long-term management strategy.

Addressing Nitrate in California’s Drinking Water Technical Report 6: Drinking Water Treatment for Nitrate

University of California, Davis (UC Davis) | July 2nd, 2012

The purpose of the first three sections of this document is to provide a detailed guide to the current state of nitrate treatment alternatives that can be used as a refe

The purpose of the first three sections of this document is to provide a detailed guide to the current state of nitrate treatment alternatives that can be used as a reference tool for the drinking water community. The remainder of this document focuses on nitrate treatment of drinking water in California and specifically in the Tulare Lake Basin and the Salinas Valley.