Managed Environmental Water Use Efficiency: Evidence in Practice

University of California, Berkeley (UC Berkeley) | May 12th, 2006

The California Water Plan Update 2005 first introduced the term Managed Environmental Water Use Efficiency (MEWUE). Specifically, it defines MEWUE as a “mechanism to an

The California Water Plan Update 2005 first introduced the term Managed Environmental Water Use Efficiency (MEWUE). Specifically, it defines MEWUE as a “mechanism to analyze alternative uses of managed environmental water to determine which allocation of a given amount of water will maximize environmental benefits, and as a means to improve decision-making over time.” While MEWUE is a new term, we found several instances where managers maximized environmental benefit from a given amount of water in current practice. This paper demonstrates and analyzes current applications of MEWUE. It then provides the Department of Water Resources with the following recommendations to advance the concept and formally incorporate it into environmental water management: Formalize a MEWUE Policy to clearly state that the goal of MEWUE is a management strategy to maximize environmental benefit and not a water conservation policy. Develop Best Management Practices to increase understanding, provide guidance, and encourage use of MEWUE. Operate a MEWUE Pilot to learn more about the way MEWUE works, understand its strengths, and improve on its weaknesses. Facilitate an Environmental Water Market by applying experience and infrastructure to provide solutions for projects that require more water.

Managing California’s Freshwater Ecosystems: Lessons from the 2012–16 Drought

Public Policy Institute of California (PPIC) | November 9th, 2017

The 2012–16 drought caused unprecedented stress to California’s ecosystems and pushed many native species to the brink of extinction. It also tested the laws, policie

The 2012–16 drought caused unprecedented stress to California’s ecosystems and pushed many native species to the brink of extinction. It also tested the laws, policies, and institutions charged with protecting the environment. Eight case studies on environmental water management during the drought reveal both strengths and weaknesses in federal, state, and local response that can inform how California addresses future droughts.

Managing California’s Water: From Conflict to Reconciliation

Public Policy Institute of California (PPIC) | April 5th, 2011

In this book, we explore solutions for the modern era, when water management must become more balanced and flexible to support both economic prosperity and environmental

In this book, we explore solutions for the modern era, when water management must become more balanced and flexible to support both economic prosperity and environmental sustainability. We start by reviewing the history of how California has adapted to changes and conflicts in water management in the past—slowly, controversially, and imperfectly—but with remarkable success. We then lay out a variety of promising principles and directions for improving water management in California for contemporary and anticipated future conditions.

Managing diversions in unregulated streams using a modified percent-of-flow approach

Freshwater Biology (Wiley) | August 22nd, 2017

In Mediterranean-type river systems stream flows are naturally low in summer and autumn. This pattern is often exacerbated by over-exploitation of water resources during

In Mediterranean-type river systems stream flows are naturally low in summer and autumn. This pattern is often exacerbated by over-exploitation of water resources during the dry season, which has implications for managing flows for both environmental and human needs. Mediterranean systems are characterised by strong inter- and intra-annual variability with almost all precipitation occurring in winter months followed by summer droughts with little or no rainfall, and extreme year-to-year variation ranging from intense winter storms to year-round drought (Gasith & Resh, 1999; Power, Kupferberg, Cooper, & Deas, 2015; Power, Parker, & Dietrich, 2008). The seasonal pattern of precipitation in Mediterranean climatic regions results in water availability and demand being out-of-phase; precipitation and runoff occur (almost exclusively) in winter when human demands are lowest, and precipitation is virtually non-existent in summer months when human demand is greatest (Kondolf & Batalla, 2005; Merenlender & Matella, 2013). As a result, rivers in Mediterranean climates tend to have a high degree of alteration with streamsdiverted and dammed to provide scarce water for human use (Kondolf, Podolak, & Grantham, 2013; Marr et al., 2009; Moyle, 2013). While the biophysical responses to alterations of land use, vegetation and hydrology are similar in Mediterranean and other climatic regions, the magnitude of responses tends to be intensified in Mediterranean systems. For example prolonged dry season flows may result in lower dissolved oxygen, higher temperatures and concentration of contaminants among other impacts (Cooper, Lake, Sabater, Melack, & Sabo, 2013). Climate change and increasing frequency and severity of drought promise to increase the conflict between human needs and ecological needs over time (Arthington, 2012).

Managing Freshwater Discharge to the San Francisco Bay/Sacramento-San Joaquin Delta Estuary―The Scientific Basis for an Estuarine Standard

San Francisco Estuary Project | October 26th, 1992

Aquatic resources of the Sacramento-San Joaquin Delta and upper portions of San Francisco Bay have undergone significant declines over the past several decades. Species c

Aquatic resources of the Sacramento-San Joaquin Delta and upper portions of San Francisco Bay have undergone significant declines over the past several decades. Species characteristic of the Delta and rivers, such as striped bass and salmon, began to decline during the late 1970s. Prolonged drought, large diversions of fresh water, and dramatic increases in populations of introduced aquatic species during the 1980s and 1990s brought a number of indigenous aquatic species to extremely low levels. Species that spend more of their lives downstream of the Delta, including Delta smelt, longfin smelt, and many zooplankton, maintained large populations through the 1970s, but declined sharply after the mid-1980s. Declines in aquatic resources have led to curtailed fishing seasons, to petitions for endangered species status, and general concern about the health of the estuarine ecosystem.

Managing Surface Water-Groundwater to Restore Fall Flows in the Cosumnes River

American Society of Civil Engineers (ASCE) | June 15th, 2004

Declining fall flows are limiting the ability of the Cosumnes River to support large fall runs of Chinook salmon. Management scenarios linking surface water and g

Declining fall flows are limiting the ability of the Cosumnes River to support large fall runs of Chinook salmon. Management scenarios linking surface water and groundwater alternatives to provide sufficient fall flows are examined using groundwater flow and channel routing models. Results show that groundwater overdraft in the basin has converted the river to a predominantly losing stream, practically eliminating base flows. Management alternatives to increase net recharge for example, pumping reductions were examined along with surface water augmentation options. Using a minimum depth standard for fish passage, average surface water flow deficits were computed for the migration period of Chinook salmon. Groundwater deficits were evaluated by comparing simulated current groundwater conditions with conditions under various scenarios. Increases in net recharge on the order of 200 to 300 million m3/year would be required to reconnect the regional aquifer with the channel and in turn reestablish perennial base flows. Options that combine surface water augmentation with groundwater management are most likely to ensure sufficient river flows in the short term and to support long-term restoration of regional groundwater levels.

Marine heatwaves need clear definitions so coastal communities can adapt

Nature Portfolio (Springer Nature) | April 3rd, 2023

Mark/Recapture Experiments at Clifton Court Forebay to Estimate Pre-Screening Loss to Juvenile Fishes: 1976-1993

California Department of Fish and Wildlife (CDFW) | September 30th, 1997

From October 1976 through November 1993, the California Department of Fish and Game conducted mark/recapture experiments at Clifton Court Forebay, designed to estimate pr

From October 1976 through November 1993, the California Department of Fish and Game conducted mark/recapture experiments at Clifton Court Forebay, designed to estimate pre-screen loss to entrained juvenile fishes. Ten studies were conducted; eight evaluated losses to hatchery-reared juvenile chinook salmon, and two evaluated losses to hatchery-reared juvenile striped bass. Pre-screen loss was calculated from the proportion of marked fish released at the radial gates that were subsequently recaptured during salvage operations at Skinner Fish Facility. The proportion was adjusted for handling mortality, fish facility louver effiCiency, and any subsampling at the facility. Studies were conducted across a wide range of environmental conditions and State Water Project operations, with a wide range in the size ofexperimental fish. Pre-screen loss estimates for juvenile chinook salmon were 63-99%. Potential biases in estimates of pre-screen loss may be due to (1) the calculation for pre-screen loss, (2) underrepresentative and over-representative salvage of experimental fish at Skinner Fish Facility, and (3) the introduction of experimental fish directly into Clifton Court Forebay. A multiple-regression analysis of pre-screen loss to juvenile salmon showed that 91% of the variance in pre-screen loss can be explained by export rate, experimental fish size, and water temperature. 

Measuring Cost-Effectiveness of Environmental Water Transactions

Klamath Riverkeeper | August 4th, 2016

The diversion, storage and consumptive use of water in the western United States (US) has drastically altered streamflow, water quality and a raft of ecological, social a

The diversion, storage and consumptive use of water in the western United States (US) has drastically altered streamflow, water quality and a raft of ecological, social and economic goods and services. Over the last fifty years, western states have begun to address this problem through a range of approaches. Water quality regulations, endangered species protections, application of the public trust doctrine to water allocations and other regulatory approaches reflect an effort to prevent further degradation of streamflow and associated values. For example, in Oregon, minimum streamflow requirements created in the 1950s were converted into full-fledged instream water rights in the 1980s and 1990s to limit further appropriations of water for out-of-stream use. Unfortunately, as junior (or low) priority rights, these rights do not serve to restore flow to already dewatered streams. In other cases, both large and small, regulatory enforcement has led to real improvements in water for the environment. In California, the protections afforded to Mono Lake water levels and the re-dedication of contract water to environmental uses under the Central Valley Project Improvement Act, are but two examples. However, the controversy, costs and lengthy time span of dedicating water to the environment through litigation and regulatory approaches are unappealing to some conservation groups, particularly those that prefer to collaborate and purchase water rather than litigate to achieve streamflow restoration. An alternative approach to meet streamflow restoration needs is to proactively negotiate in the “water market” for the acquisition of existing out-of-stream rights or for changes in water use and management in order to benefit the environment. These transactions result in “environmental flows,” including the dedication or protection of water instream or the provision of water to Roughly 80% of California’s developed water supply is used for agricultural irrigation.*

Mercury on a landscape scale—Balancing regional export with wildlife health

U.S. Geological Survey (USGS) | June 26th, 2018

The Cosumnes River watershed requires a 57–64 percent reduction in loads to meet the new Delta methylmercury (MeHg) total maximum daily load allocation, established by

The Cosumnes River watershed requires a 57–64 percent reduction in loads to meet the new Delta methylmercury (MeHg) total maximum daily load allocation, established by the Central Valley Regional Water Quality Control Board. Because there are no large point sources of MeHg in the watershed, the focus of MeHg load reductions will fall upon non-point sources, particularly the expansive wetlands considered to be a primary source of MeHg in the region. Few management practices have been implemented and tested in order to meet load reductions in managed wetlands, but recent efforts have shown promise. This project examines a treatment approach to reduce MeHg loads to the Sacramento-San Joaquin River Delta by creating open-water deep cells with a small footprint at the downstream end of wetlands to promote net demethylation of MeHg and to minimize MeHg and Hg loads exiting wetlands at the Cosumnes River Preserve. Specifically, the deep cells were were located immediately up gradient of the wetland’s outflow weir and were deep enough (75–91 centimeter depth) to be vegetation-free. The topographic and hydrologic structure of each treatment wetland was modified to include open-water deep cells so that the removal of aqueous MeHg might be enhanced through (1) particle settling, (2) photo-degradation, and (3) benthic microbial demethylation. These deep cells were, therefore, expected to clean MeHg from surface water prior to its discharge to the Cosumnes River and the downstream Delta.