The paradox of irrigation efficiency

American Association for the Advancement of Science (AAAS) | August 24th, 2018

Reconciling higher freshwater demands with finite freshwater resources remains one of the great policy dilemmas. Given that crop irrigation constitutes 70% of global wate

Reconciling higher freshwater demands with finite freshwater resources remains one of the great policy dilemmas. Given that crop irrigation constitutes 70% of global water extractions, which contributes up to 40% of globally available calories (1), governments often support increases in irrigation efficiency (IE), promoting advanced technologies to improve the “crop per drop.” This provides private benefits to irrigators and is justified, in part, on the premise that increases in IE “save” water for reallocation to other sectors, including cities and the environment. Yet substantial scientific evidence (2) has long shown that increased IE rarely delivers the presumed public-good benefits of increased water availability. Decision-makers typically have not known or understood the importance of basin-scale water accounting or of the behavioral responses of irrigators to subsidies to increase IE. We show that to mitigate global water scarcity, increases in IE must be accompanied by robust water accounting and measurements, a cap on extractions, an assessment of uncertainties, the valuation of trade-offs, and a better understanding of the incentives and behavior of irrigators.

The potential of urban irrigation for counteracting carbon-climate feedback

Nature Portfolio (Springer Nature) | March 18th, 2024

The seven Colorado River Basin states letter to the U.S. Bureau of Reclamation, 5/22/23

U.S. Bureau of Reclamation (USBR) | May 22nd, 2023

The Untapped Potential of California’s Urban Water Supply: Water Efficiency, Water Reuse, and Stormwater Capture

Pacific Institute | April 12th, 2022

In this assessment, we quantify the potential for a range of water strategies in urbanized parts of California to both reduce inefficient and wasteful water uses and expa

In this assessment, we quantify the potential for a range of water strategies in urbanized parts of California to both reduce inefficient and wasteful water uses and expand local water supplies. This assessment finds that urban water-use efficiency improvements could reduce statewide urban water use by 2.0 million to 3.1 million acre-feet per year (AFY). The reuse potential of municipal wastewater is 1.8 million to 2.1 million AFY, and the stormwater capture potential is 580,000 AFY in a dry year to as much as 3.0 million AFY in a wet year. Previous assessments have shown that these efficiency and supply options are more cost effective than traditional – and increasingly hard to implement – options to expand supply. Programs to tap this potential would tremendously help solve California’s long-standing water problems.

The Untapped Potential of California’s Water Supply

Pacific Institute | June 10th, 2014

California could be saving up to 14 million acre-feet of untapped water – providing more than the amount of water used in all of California’s cities in one year – w

California could be saving up to 14 million acre-feet of untapped water – providing more than the amount of water used in all of California’s cities in one year – with an aggressive statewide effort to use water-saving practices, reuse water, and capture lost stormwater, according to a new analysis released by the Pacific Institute and the Natural Resources Defense Council. “Our current approach to water use is unsustainable, but that doesn’t mean there isn’t enough water to meet our needs,” said Kate Poole, NRDC senior attorney with the water program. “At a time when every drop counts, we need to employ sensible and cost-effective 21st century solutions that will help us reduce uses today while promising new, resilient supplies for cities and farms tomorrow.” “As climate change brings more extreme weather, including droughts, ramping up forward-thinking solutions now will help us be more resilient,” said Peter Gleick, president of the Pacific Institute. “With widespread adoption of available water conservation and efficiency improvements, demand can be met more readily, less expensively, and with less pressure on our tapped-out rivers and groundwater basins. Moreover, water reuse and stormwater capture can help boost local supplies.”

Towards sharing water better with near real-time maps on evaporative water use by crops and natural vegetation

Nature Portfolio (Springer Nature) | January 15th, 2024

The combination of advancements in evapotranspiration theory, eddy covariance flux measurements of water vapour and satellite remote sensing are putting technology on the

The combination of advancements in evapotranspiration theory, eddy covariance flux measurements of water vapour and satellite remote sensing are putting technology on the verge of producing information on evapotranspiration with unprecedented coverage and resolution. The OpenET project provides this information to farmers and land and water managers for better water practice.

Turf Replacement Program Impacts on Households and Ratepayers: An Analysis for the City of Los Angeles

University of California, Los Angeles (UCLA) | September 30th, 2016

Ongoing severe drought and climate change continue to strain the Los Angeles region’s water supply and have forced the City to institute water savings goals (Garcetti,

Ongoing severe drought and climate change continue to strain the Los Angeles region’s water supply and have forced the City to institute water savings goals (Garcetti, 2014). Turf replacement programs, which aim to encourage residents to replace their lawn with less water intensive landscaping, may offer benefits as part of a larger package of conservation measures. More than half of residential water use is allocated for outdoor watering (approximately 54%) (Firestone, 2015). Outdoor water use is typically considered discretionary while indoor water use is generally considered essential, making outdoor water use a good target for conservation efforts. In order to encourage turf replacement, the city launched a turf replacement program in 2009. Commercial and residential customers can receive a rebate from the utility when they replace their lawns with less water intensive landscaping. Currently, the city is offering a rebate of $1.75 per sq. ft. up to 1,500 sq. ft. This report seeks to answer two questions regarding the turf replacement program. First, under what conditions does participation in the turf replacement program provide financial benefits to households? Second, is the turf replacement program a reasonably cost effective investment for utilities and ratepayers?

UN-Water Analytical Brief on Unconventional Water Resources

United Nations (UN) | June 5th, 2020

Increasing water scarcity is recognized as a key challenge to sustainable development and major cause of conflict, social unrest and changes to traditional migration rout

Increasing water scarcity is recognized as a key challenge to sustainable development and major cause of conflict, social unrest and changes to traditional migration routes and new migration patterns. At the same time water is increasingly considered as an instrument for international cooperation to support food production, livelihoods, ecosystems, climate change adaption, and sustainable development. As water scarcity is set to continue and intensify in dry areas, the world at large is in danger of leaving the water scarcity challenge to future generations who will be confronted with the consequences of today’s practices. Thus, water-scarce areas must sustainably access and utilize every available option for water resources in order to minimize the pressure that continues to grow. Conventional water provisioning approaches relying on snowfall, rainfall and river runoff are not enough to meet growing freshwater demand in water-scarce areas. Considering the water-related sustainable development challenges in arid regions, unconventional water resources are an emerging opportunity to narrow the water demand-supply gap. There are fragmented, but growing, examples of using unconventional water resources across the world to boost water supplies to address water scarcity.

Unintended consequences of water conservation on the use of treated municipal wastewater

Nature Portfolio (Springer Nature) | May 11th, 2020

Municipal water managers are intensifying efforts to reduce urban water use and increase the reliability of local water supplies to combat rising water scarcity and droug

Municipal water managers are intensifying efforts to reduce urban water use and increase the reliability of local water supplies to combat rising water scarcity and drought. Incentivizing increases in water-use efficiency and mandating conservation are two strategies to rein in demand. Concurrently, local water supplies are being augmented through investments in reclaiming and treating municipal wastewater. Although reducing urban water consumption is necessary to deal with population growth and a more variable climate, it does come at a cost. In particular, cutting back on indoor water consumption impacts the generation and quality of wastewater, which can have widespread and underappreciated consequences on human society and the environment. Here, to quantify these impacts, we tracked monthly effluent flow, salinity levels and the properties of 34 wastewater treatment plants throughout Southern California from 2013 to 2017—a period that included extreme drought and abundant precipitation. Our analysis demonstrates that conservation measures significantly reduced effluent flow and increased effluent salinity (P value ≤ 0.05). Our findings further highlight the need for policymakers to recognize the interdependencies and complexities within a water system.

Urban and Agricultural Water Use in California, 1960–2015

Pacific Institute | June 22nd, 2020

Water is the lifeblood of California. It provides for the household needs of 40 million people. It generates electricity and cools power plants. It supports one of the mo

Water is the lifeblood of California. It provides for the household needs of 40 million people. It generates electricity and cools power plants. It supports one of the most productive agricultural regions in the world and various commercial and industrial activities, ultimately fueling the fifth largest economy in the world. Water is also critical to the health and viability of the state’s diverse aquatic and terrestrial ecosystems. This paper examines statewide urban and agricultural water-use trends from 1960 to 2015 using data from the California Department of Water Resources (DWR). We find that California has experienced a dramatic decoupling between water use and growth. Since 1967, California’s population has doubled, and its economic output has increased by a factor of five. Yet statewide water use increased by only 20 percent over this period due to improvements in urban and agricultural efficiency, as well as a shift to higher-value crops and less water-intensive commercial and industrial activities.  Despite positive signs, water use in California remains high. Across the state, rivers and streams are under stress from overuse, and groundwater is over-tapped. Climate change and continued growth are increasing pressure on the state’s water resources, including on water supply, demand, and quality. To address these challenges, we must continue and even expand efforts to improve the water-use efficiency of our homes, businesses, industries, and farms. Moreover, we urge the state to improve data collection and online systems to make data more easily, quickly, and readily available.