Urban Water Use Efficiency (Resource Management Strategy)

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

During the past few decades, Californians have made great progress in urban water use efficiency. Once viewed and invoked primarily as a temporary strategy in response to

During the past few decades, Californians have made great progress in urban water use efficiency. Once viewed and invoked primarily as a temporary strategy in response to a drought or emergency water shortage situation, water use efficiency has become a permanent part of the long-term management of California’s water supply. At the individual level, the benefits of water use efficiency may appear small, incremental, or difficult to see, but when Californians act together as a community to conserve water, the cumulative effect is significant, and the benefits are widespread. There are several factors that have contributed to increased water use efficiency: outreach efforts that have increased awareness and changed behaviors; urban water suppliers’ implementation of demand management measures (DMMs); plumbing codes requiring more efficient fixtures; the Model Water Efficient Landscape Ordinance (MWELO); advances in irrigation technology; new technologies in the commercial, institutional, and industrial (CII) sectors; and mandates requiring that unmetered connections become metered. But, with tighter environmental constraints on the Sacramento-San Joaquin River Delta (Delta), increasing population, and the necessity of adapting to climate change, even greater efficiencies will be needed and are achievable. When faced with an increasing demand for water, water agencies can consider options for increasing supplies or reducing demand, or a combination of both, to meet this need. Increasing water supply can be expensive and can include costs of purchasing additional water, capital cost of production and distribution systems, water supply treatment facilities, energy costs, and wastewater treatment facilities. Reducing demand through increased water use efficiency is generally lower cost and quicker to implement.

Using Conceptual Models and Decision-Support Tools to Guide Ecosystem Restoration Planning and Adaptive Management: An Example from the Sacramento–San Joaquin Delta, California

University of California, Davis (UC Davis) | October 1st, 2012

The Sacramento–San Joaquin Delta (the Delta) is located on the western edge of California’s Central Valley and is of critical ecological and economic importance. H

The Sacramento–San Joaquin Delta (the Delta) is located on the western edge of California’s Central Valley and is of critical ecological and economic importance. However, ecosystem alterations for human uses changed many of the Delta’s natural processes, and it is now considered in need of restoration. An approach was developed to evaluate and rank restoration actions in the Delta under the Ecosystem Restoration Program’s Delta Regional Ecosystem Restoration Implementation Plan (DRERIP). The DRERIP approach provides an explicit framework for evaluating restoration actions, using linked conceptual models, an action evaluation procedure, and a decision-support tool. Conceptual models allow scientists and managers to synthesize scientific information and make qualitative predictions about ecosystem function and restoration outcomes to guide and focus restoration efforts. The action evaluation procedure is a structured assessment of restoration actions. The procedure clearly describes actions to be evaluated, assesses the magnitude (importance and scale) and certainty of anticipated ecological outcomes, estimates degrees of worth (achieving intended outcomes) and risk (causing adverse consequences), evaluates the reversibility of the action, and identifies opportunities for learning. The values for worthiness, risk, reversibility, and learning opportunity are used in the decision- support tool to determine the fate of a proposed action. The decision-support tool is a structured decision tree that determines the disposition of an action: whether a restoration project should be discarded, revised with a different approach and re-evaluated, or implemented; and, if implemented, at what scale (targeted research, pilot project, or full implementation). The DRERIP approach provides managers with a valuable tool for restoration planning, and a foundation for integration with quantitative methods for a comprehensive ecosystem restoration plan.

Utah's Land, Water and Air 2023 Report to the Governor and Legislature

Utah State University | October 19th, 2023

This report serves as a 2023 snapshot of key issues and concerns with Utah’s shared resources. It highlights gathered data that is available to provide context to thes

This report serves as a 2023 snapshot of key issues and concerns with Utah’s shared resources. It highlights gathered data that is available to provide context to these issues, as well as identifies areas where more study is needed. Addressing these challenges will enable Utah policymakers to make informed decisions for the future. Under the authorship of 43 researchers and experts and the general guidance of 49 advisory committee members, the report outlines 32 issues and trends to pay attention to in the coming months and years.

Wastewater Reuse for Agriculture: Development of a Regional Water Reuse Decision-Support Model (RWRM) for Cost-Effective Irrigation Sources

American Chemical Society (ACS) | August 8th, 2016

Water scarcity has become a critical problem in many semiarid and arid regions. The single largest water use in such regions is for crop irrigation, which typically relie

Water scarcity has become a critical problem in many semiarid and arid regions. The single largest water use in such regions is for crop irrigation, which typically relies on groundwater and surface water sources. With increasing stress on these traditional water sources, it is important to consider alternative irrigation sources for areas with limited freshwater resources. One potential irrigation water resource is treated wastewater for agricultural fields located near urban centers. In addition, treated wastewater can contribute an appreciable amount of necessary nutrients for plants. The suitability of reclaimed water for specific applications depends on water quality and usage requirements. The main factors that determine the suitability of recycled water for agricultural irrigation are salinity, heavy metals, and pathogens, which cause adverse effects on human, plants, and soils. In this paper, we develop a regional water reuse decision-support model (RWRM) using the general algebraic modeling system to analyze the cost-effectiveness of alternative treatment trains to generate irrigation water from reclaimed wastewater, with the irrigation water designed to meet crop requirements as well as California’s wastewater reuse regulations (Title 22). Using a cost-minimization framework, least-cost solutions consisting of treatment processes and their intensities (blending ratios) are identified to produce alternative irrigation sources for citrus and turfgrass. Our analysis illustrates the benefits of employing an optimization framework and flexible treatment design to identify cost-effective blending opportunities that may produce high-quality irrigation water for a wide range of end uses.

Water Accounting in Western US, Australia, and Spain: Comparative Analysis

American Society of Civil Engineers (ASCE) | January 10th, 2020

Water and climate: Recognize anthropogenic drought

Nature Portfolio (Springer Nature) | August 27th, 2015

Water and Energy Sector Vulnerability to Climate Warming in the Sierra Nevada: Water Year Classification in Non?Stationary Climates

California Energy Commission (CEC) | July 31st, 2012

This paper explores the sensitivity of water indexing methods to climate change scenarios to better understand how water management decisions and allocations will be affe

This paper explores the sensitivity of water indexing methods to climate change scenarios to better understand how water management decisions and allocations will be affected by climate change. Many water management decisions, such as environmental flow requirements and water supply allocations, are based on numerical “water year type” designations. Water year type designations vary by region and index, but most are defined by some measure of runoff in the current water year compared to average historical runoff, with numerical thresholds categorizing year types. Climate change is anticipated to alter the timing and volume of runoff, and change the relative frequency of water year types as presently defined. California’s Sacramento Valley and San Joaquin Valley Indices are used as a case study to examine climatic changes. These indices provide a framework for allocating and transferring water among users. Streamflow estimates for 1951–2099 from the climate-forced Variable Infiltration Capacity hydrologic model are used to estimate potential changes in runoff and water year type frequency, using six global circulation models for the A2 and B1 emissions scenarios. Results vary by emissions scenario and global circulation model, but indicate that critically dry water years in the Sacramento Valley and San Joaquin Valley are expected to be about 8 percent and 32 percent more likely by the latter half of the twenty-first century, respectively, if water year type definitions remain unchanged. If current water year type thresholds are maintained, more years will be classified as dry and less water will be allocated for environmental outflows, perhaps failing to provide adequate hydrologic variability to support species, habitats, and ecosystems. If thresholds are redefined to reflect the historical distribution of year types, the burden of climate change falls to consumptive users and water exporters. This case study illustrates how water policy and allocation frameworks were designed assuming climatic stationarity, and that adapting water policy (or maintaining the status quo) affects which users bear the burden of climate change.

Water and the California economy

Public Policy Institute of California (PPIC) | May 17th, 2012

California’s economy can grow and prosper despite droughts and water shortages caused by a changing climate—but only if threats to the water system are addressed now.

California’s economy can grow and prosper despite droughts and water shortages caused by a changing climate—but only if threats to the water system are addressed now. So far, innovative water management has supported the needs of a growing population but serious concerns remain, including water supply reliability and declining groundwater basins.

Water and the COVID-19 Pandemic Impacts on Municipal Water Demand

Pacific Institute | July 2nd, 2020

Water and the Future of the San Joaquin Valley

Public Policy Institute of California (PPIC) | February 14th, 2019

The San Joaquin Valley—California’s largest agricultural region and an important contributor to the nation’s food supply—is in a time of great change. The valle

The San Joaquin Valley—California’s largest agricultural region and an important contributor to the nation’s food supply—is in a time of great change. The valley is ground zero for many of California’s most difficult water management problems—including groundwater overdraft, drinking water contamination, and declines in habitat and native species. Local water supplies are limited, particularly in the southern half of the region. To irrigate their crops, many farmers use water imported from the Sacramento–San Joaquin Delta. But in many places farmers have also relied on groundwater overdraft—pumping groundwater in excess of the rate at which it is replenished. Worsening droughts, increasing regulations to protect endangered native fishes, and growing demand by Southern California for Delta imports have compounded surface water scarcity. The state’s Sustainable Groundwater Management Act (SGMA) requires local water users to bring groundwater use to sustainable levels by the early 2040s. This will have a broad impact on valley agriculture and the regional economy in coming years—likely including some permanent idling of farmland. This report explores three key challenges facing the San Joaquin Valley and reviews the most promising approaches to address them:  Balancing water supplies and demands. To close the groundwater deficit, groundwater sustainability agencies in the valley’s overdrafted basins will have to augment supplies, reduce demands, or use some combination of these two approaches. A range of options are under consideration but they are not equally effective or practical.  Addressing groundwater quality challenges. Poor groundwater quality impairs drinking water supplies in disadvantaged rural communities, reduces long-term agricultural prosperity, and degrades ecosystems. Providing safe drinking water is an urgent priority. Over the longer term, parties will also need to manage water quantity and quality together, to take advantage of synergies and avoid unintended consequences. The necessary coordination will be challenging because the various programs addressing valley water quality issues are carried out by numerous local and regional entities, whose lines of responsibility and geographic boundaries do not neatly align.  Fostering beneficial water and land use transitions. Effectively addressing water scarcity and the resulting land use changes in the San Joaquin Valley offers opportunities to put lands coming out of production to good use—and gain “more pop per drop” from limited water resources. Multiple-benefit approaches to water and land management can enhance groundwater recharge and improve air and water quality. They can also promote healthier soils, new recreational opportunities, additional flood protection, improved habitat, and new revenue streams for private landowners engaging in conservation-oriented management. Addressing these complex and intertwined issues requires significant changes in water and land management and a major ramp-up in cooperation and coordination among a wide circle of stakeholders. Pursuing solutions that deliver multiple benefits will boost the chances of success overall. The entire region—and California as a whole—will benefit if solutions to these challenges are cost-effective and support the valley’s economy while improving public health and the natural environment.