Multiscale Assessment of Agricultural Consumptive Water Use in California's Central Valley

American Geophysical Union (AGU) | May 4th, 2021

Municipal Deliveries of Colorado River Basin Water: New Report Examines 100 Cities and Agencies

Pacific Institute | June 12th, 2011

The Pacific Institute’s Municipal Deliveries of Colorado River Basin Water documents population and water delivery information and trends for 100 cities and agencies th

The Pacific Institute’s Municipal Deliveries of Colorado River Basin Water documents population and water delivery information and trends for 100 cities and agencies that deliver water from the Colorado River basin. Since 1990, the number of people in the United States and Mexico who use Colorado River basin water has increased by more than 10 million -– but their overall per capita water use declined by an average of at least one percent per year from 1990 to 2008. The new report provides -– for the first time -– real numbers on the extraordinary population growth among cities that depend on water from the basin and on changing water delivery rates by these cities. Author Michael Cohen, senior research associate, documents the substantial water-efficiency gains made over the past twenty years by agencies delivering water from the Colorado River basin -– even by agencies and cities such as Flagstaff that already had relatively low per capita delivery rates in 1990.

Municipal Recycled Water (Resource Management Strategy)

California Department of Water Resources (DWR) | July 29th, 2016

California is increasing its integration of municipal recycled water into its water supply portfolio. In some regions of the state, recycled water meets approximately 7 p

California is increasing its integration of municipal recycled water into its water supply portfolio. In some regions of the state, recycled water meets approximately 7 percent of water supply demands. Although the statewide total is an increase since California Water Plan Update 2009 (Update 2009) was released, it is still far short of previously established goals. Municipal recycled water benefits the state and individual water users by reducing long-distance water conveyance needs, providing local water supplies, and being a drought-resistant resource. This resource management strategy report will describe the current status of recycled water in California, what some of the challenges are to its increasing use, and the resources needed to continue to increase municipal recycled water use.

No-tillage and high-residue practices reduce soil water evaporation

California Agriculture (UCANR) | April 1st, 2012

Reducing tillage and maintaining crop residues on the soil surface could improve the water use efficiency of California crop production. In two field studies co

Reducing tillage and maintaining crop residues on the soil surface could improve the water use efficiency of California crop production. In two field studies comparing no-tillage with standard tillage operations (following wheat silage harvest and before corn seeding), we estimated that 0.89 and 0.97 inches more water was retained in the no-tillage soil than in the tilled soil. In three field studies on residue coverage, we recorded that about 0.56, 0.58 and 0.42 inches more water was retained in residue-covered soil than in bare soil following 6 to 7 days of overhead sprinkler irrigation. Assuming a seasonal crop evapotranspiration demand of 30 inches, coupling no-tillage with practices preserving high residues could reduce summer soil evaporative losses by about 4 inches (13%). However, practical factors, including the need for different equipment and management approaches, will need to be considered before adopting these practices.

Observational evidence of increased afternoon rainfall downwind of irrigated areas

Nature Portfolio (Springer Nature) | April 10th, 2025

Irrigation plays a vital role in addressing the growing food demand of an increasing global population. It represents one of the most critical and direct human interventi

Irrigation plays a vital role in addressing the growing food demand of an increasing global population. It represents one of the most critical and direct human interventions on the coupled water and energy cycles. As irrigated farmland continues to expand, understanding the climate impact of extensive irrigation becomes increasingly important. Yet, the effect on rainfall patterns near irrigated areas remains unclear. Here, using two global, high-resolution, sub-daily precipitation datasets, we show that afternoon rain events occur more often 10 km to 50 km downwind and less often upwind of extensively irrigated land. However, we also find that the total amount of heavy afternoon rain downwind of irrigated areas is lower than upwind. Our results establish large-scale observational evidence of the local precipitation dynamics surrounding irrigated areas; these insights will help constrain the representation of these processes in next-generation climate and weather forecasting models and provide valuable insights for regional water management.

On-farm flood capture could reduce groundwater overdraft in Kings River Basin

California Agriculture (UCANR) | November 16th, 2016

Chronic groundwater overdraft threatens agricultural sustainability in California’s Central Valley. Diverting flood flows onto farmland for groundwater rechar

Chronic groundwater overdraft threatens agricultural sustainability in California’s Central Valley. Diverting flood flows onto farmland for groundwater recharge offers an opportunity to help address this challenge. We studied the infiltration rate of floodwater diverted from the Kings River at a turnout upstream of the James Weir onto adjoining cropland; and calculated how much land would be necessary to capture the available floodwater, how much recharge of groundwater might be achieved, and the costs. The 1,000-acre pilot study included fields growing tomatoes, wine grapes, alfalfa and pistachios. Flood flows diverted onto vineyards infiltrated at an average rate of 2.5 inches per day under sustained flooding. At that relatively high infiltration rate, 10 acres are needed to capture one CFS of diverted flood flow. We considered these findings in the context of regional expansion. Based upon a 30-year record of Kings Basin surplus flood flows, we estimate 30,000 acres operated for on-farm flood recharge would have had the capacity to capture 80% of available flood flows and potentially offset overdraft rates in the Kings Basin. Costs of on-farm flood capture for this study were estimated at $36 per acre-foot, less than the cost for surface water storage and dedicated recharge basins.

One Water LA 2040 Plan

City of Los Angeles | April 30th, 2018

The purpose of the One Water LA 2040 Plan (Plan) is to increase sustainable water management for the City of Los Angeles (City). The City launched One Water LA with two p

The purpose of the One Water LA 2040 Plan (Plan) is to increase sustainable water management for the City of Los Angeles (City). The City launched One Water LA with two primary goals: 1. Develop a vision and implementation strategy to more sustainably and cost-effectively manage water. 2. Identify ways for City departments and regional agencies to integrate their water management strategies. Los Angeles Sanitation (LASAN) and the Los Angeles Department of Water and Power (LADWP) led the Plan's development, partnering with other City departments, regional agencies, academia, the business community, and other stakeholders. The Plan provides a comprehensive strategy for managing water in a more integrated, collaborative, and sustainable way through new project, program, and policy opportunities. The Implementation Strategy provides a roadmap to make the One Water LA Vision a reality. Additional water projects, programs, or policies that are the sole responsibility of one agency, including LADWP's aqueduct or groundwater remediation project, are contained in each agency's appropriate plans. This plan is divided into an Executive Summary and ten sections. Executive Summary Volume One: Summary Report Volume Two: Wastewater Facilities Plan Volume Three: Stormwater and Urban Runoff Facilities Plan Volume Four: Los Angeles River Flow Study Volume Five: Integration Opportunities Analysis Volume Six: Climate Risk and Resilience Assessment for Wastewater and Stormwater Infrastructure Volume Seven: Implementation Strategy Supporting Documents Volume Eight: Technical Support Materials Volume Nine: Stakeholder Engagement Materials, Part 1, Part 2, Part 3 Volume Ten: Programmatic Environmental Impact Report (in progress)

Optimal residential water conservation strategies considering related energy in California

American Geophysical Union (AGU) | May 24th, 2015

Overview of Greywater Reuse: The Potential of Greywater Systems to Aid Sustainable Water Management

Pacific Institute | November 18th, 2010

As pressures on freshwater resources grow around the world and as new sources of supply become increasingly scarce, expensive, or politically controversial, efforts are u

As pressures on freshwater resources grow around the world and as new sources of supply become increasingly scarce, expensive, or politically controversial, efforts are underway to identify new ways of meeting water needs by expanding the usefulness of alternative sources of water previously considered unusable. Greywater reuse is one such strategy. Greywater is the relatively high-quality wastewater generated from household uses like bathing and washing clothes. When reused either onsite or nearby, greywater has the potential to reduce the demand for new water supply, reduce the energy and carbon footprint of water services, and meet a wide range of social and economic needs. In particular, the reuse of greywater can help reduce demand for more costly high-quality potable water. The 2010 report Overview of Greywater Reuse: the Potential of Greywater Systems to Aid Sustainable Water Management analyzes how, as a key strategy that reduces demand, greywater reuse can improve the resilience of water systems to the impacts of climate change. It also serves as a relatively secure or drought-resistant source of water supply because presumably greywater generated from showers and washing machines will continue, if at a reduced rate. And in helping displace demand for water, greywater reuse can help reduce conflicts over water and reduce the demand for new water supply projects as a result of climate change. The research shows that when the systems are designed and implemented properly, possible public health concerns with using different water qualities can be addressed. As greywater reuse becomes more widely adopted, regulations can be put in place to ensure that water quality is appropriately matched to water need. This paper provides a broad overview of the state of greywater implementation and policy, with a special emphasis on the Middle East. It examines the potential of greywater to reduce the water and energy intensity of water uses, and it analyzes key issues that must be addressed for greywater to be accepted, and implemented, at larger scales.

Paso Robles vineyard irrigation study provides benchmark data to assist future area groundwater management

California Agriculture (UCANR) | March 13th, 2018

Accurate information on irrigation water usage does not exist in many areas where groundwater is the primary water source. This lack of information will hinder

Accurate information on irrigation water usage does not exist in many areas where groundwater is the primary water source. This lack of information will hinder efforts to manage these groundwater basins sustainably according to current and future water regulations and policies. Using a low-cost methodology of irrigation-line pressure sensors connected to data loggers, we estimated irrigation applications at 84 vineyard sites in the Paso Robles Groundwater Basin over 4 years (2010–2013). We compared irrigation amounts with the preceding winter’s rainfall and with the growing season reference evapotranspiration (ETo). Over the study period, the average annual irrigation application was 11.46 inches (291 millimeters). The average annual application correlated inversely to the preceding winter’s rainfall, while the irrigation over the growing season (April–October) correlated directly with the ETo over this same period. This study provides an initial data framework that can be used by groundwater sustainability agencies to help manage groundwater in the Paso Robles area. The methodology also could be utilized in other regions to estimate regional irrigation usage while maintaining anonymity for participants.