South Coast

Intensification of hydrological drought in California by human water management

American Geophysical Union (AGU) | January 25th, 2017

Interbasin water transfers in the United States and Canada

Nature Portfolio (Springer Nature) | January 13th, 2023

Interbasin water transfers (IBTs) can have a significant impact on the environment, water availability, and economies within the basins importing and exporting water, as

Interbasin water transfers (IBTs) can have a significant impact on the environment, water availability, and economies within the basins importing and exporting water, as well as basins downstream of these water transfers. The lack of comprehensive data identifying and describing IBTs inhibits understanding of the role IBTs play in supplying water for society, as well as their collective hydrologic impact. We develop three connected datasets inventorying IBTs in the United States and Canada, including their features, geospatial details, and water transfer volumes. We surveyed the academic and gray literature, as well as local, state, and federal water agencies, to collect, process, and verify IBTs in Canada and the United States. Our comprehensive IBT datasets represent all known transfers of untreated water that cross subregion (US) or subdrainage area (CA) boundaries, characterizing a total of 641 IBT projects. The infrastructure-level data made available by these data products can be used to close water budgets, connect water supplies to water use, and better represent human impacts within hydrologic and ecosystem models.

Introducing Time-Limited Permits to California’s Riparianism

University of California, Davis (UC Davis) | December 1st, 2023

Investigation on the Feasibility of Developing Uniformwater Recycling Criteria ror Direct Potable Reuse

California State Water Resources Control Board (SWRCB) | December 1st, 2016

The population of California is projected to increase from 38 million to 50 million by the year 2049. This population increase will have a dramatic impact on the water ne

The population of California is projected to increase from 38 million to 50 million by the year 2049. This population increase will have a dramatic impact on the water needs of the State. To address this increased water need, the State will take a variety of actions as outlined in the Governor’s California Water Action Plan, first released in 2014 and recently updated in 2016 (CA Natural Resources Agency, 2016). One component of that plan is to increase the use of recycled water. The State Water Board has set a mandate of increasing the use of recycled water by 200,000 acre-foot per year (AFY) by 2020 and an additional 300,000 AFY by 2030. Although the use of recycled water for non-potable uses such as agricultural and landscape irrigation is already well established and has been regulated for decades in California, increasing the use of recycled water for both non-potable uses as well as a source of potable water (“potable reuse”) is important for the State to be able to meet this mandate. For example, groundwater replenishment (groundwater recharge), which is an indirect form of potable reuse, has the capacity to reuse 200,000 acre-feet of recycled water a year via just eight projects throughout California. Accordingly, the State Water Board revised and adopted uniform water recycling criteria for groundwater replenishment in 2014 and is in the process of establishing uniform water recycling criteria for the augmentation of surface water reservoirs used as a source of drinking water supply, which is another form of indirect potable reuse.

Irrigation Water Use in the Central Valley of California

California Department of Water Resources (DWR) | January 1st, 1985

Jet stream dynamics, hydroclimate, and fire in California from 1600 CE to present

National Academy of Sciences (NAS) | March 4th, 2019

Moisture delivery in California is largely regulated by the strength and position of the North Pacific jet stream (NPJ), winter high-altitude winds that influence regiona

Moisture delivery in California is largely regulated by the strength and position of the North Pacific jet stream (NPJ), winter high-altitude winds that influence regional hydroclimate and forest fire during the following warm season. We use climate model simulations and paleoclimate data to reconstruct winter NPJ characteristics back to 1571 CE to identify the influence of NPJ behavior on moisture and forest fire extremes in California before and during the more recent period of fire suppression. Maximum zonal NPJ velocity is lower and northward shifted and has a larger latitudinal spread during presuppression dry and high-fire extremes. Conversely, maximum zonal NPJ is higher and southward shifted, with narrower latitudinal spread during wet and low-fire extremes. These NPJ, precipitation, and fire associations hold across pre–20th-century socioecological fire regimes, including Native American burning, postcontact disruption and native population decline, and intensification of forest use during the later 19th century. Precipitation extremes and NPJ behavior remain linked in the 20th and 21st centuries, but fire extremes become uncoupled due to fire suppression after 1900. Simulated future conditions in California include more wet-season moisture as rain (and less as snow), a longer fire season, and higher temperatures, leading to drier fire-season conditions independent of 21st-century precipitation changes. Assuming continuation of current fire management practices, thermodynamic warming is expected to override the dynamical influence of the NPJ on climate–fire relationships controlling fire extremes in California. Recent widespread fires in California in association with wet extremes may be early evidence of this change.

LA Sustainable Water Project: Los Angeles City-Wide Overview

University of California, Los Angeles (UCLA) | February 1st, 2018

This report assesses the potential to improve water quality standards while integrating complementary One Water Management practices that can increase potential local wat

This report assesses the potential to improve water quality standards while integrating complementary One Water Management practices that can increase potential local water supplies for the City of Los Angeles (the City).  This final report summarizes the current practices and future opportunities at the City-owned Water Reclamation Plants and underlying groundwater basins and highlights the importance of considering all aspects of integrated water management even when dealing with water quality or supply-focused projects. Implementing watershed-scale best management practice programs to meet stormwater permit requirements will significantly improve water quality in all watersheds.  However, additional mechanisms such as increasing Low Impact Development implementation and comprehensive source tracking and source control mechanisms will be required to potentially eliminate water quality exceedances.  There are multiple efforts occurring in the City and the region to increase the recharge of recycled water into the ground and the volumes of remediated groundwater extracted. This research further assessed the impacts of potential water supply portfolios, with greater volumes of locally-supplied water, on GHG emissions and energy needs of supplying LA’s water.  Conservation will be another powerful tool to decrease our dependence on imported water.  This research demonstrates the complex interrelationships between all aspects of urban water management, including, for example, stormwater management and local water supply.

LA Sustainable Water Project: Los Angeles River Watershed

University of California, Los Angeles (UCLA) | September 1st, 2017

The LA Sustainable Water Project: Los Angeles River Watershed report explores the potential to improve water quality standards while integrating complementary One Water M

The LA Sustainable Water Project: Los Angeles River Watershed report explores the potential to improve water quality standards while integrating complementary One Water Management practices that can increase potential local water supplies for the City of Los Angeles (the City) in the highly urbanized Los Angeles River (LAR) watershed.To assess the integrated water landscape in this watershed, the report also looks at current practices and future opportunities at the Donald C Tillman, LA Glendale, and Burbank Water Reclamation Plants (WRPs) and in the underlying Upper LA River Area (ULARA) adjudicated groundwater basins. Implementing watershed-scale best management practice programs to meet stormwater permit requirements will significantly improve water quality. However, additional mechanisms such as increasing Low Impact Development implementation and comprehensive source tracking and source control mechanisms will be required to potentially eliminate water quality exceedances. The 3 WRPs in the watershed currently discharge more than 30 million gallons per day of treated wastewater into the River; an increased focus on increasing local water supply could lead to a reduction in these discharges. The combination of increased stormwater capture and increased use of recycled water in the LAR watershed could lead to lower flows in the LAR and impact habitat and recreational uses; further study is needed to characterize potential impacts and identify optimal flows for the future of the LAR. The City is leading efforts in ULARA to increase the recharge of recycled water into theground by 30,000 acre feet per year and increase the volumes of remediated groundwater extracted by around 120,000 acre feet per year. This research demonstrates the complex interrelationships between all aspects of urban water management, including stormwater management and local water supply.

LADWP Stormwater Capture Master Plan

Los Angeles Department of Water & Power (LADWP) | October 5th, 2015

To ensure a safe and reliable water supply for future generations of Angelenos, one of the City’s key strategies is to increase the local water supply and decrease the

To ensure a safe and reliable water supply for future generations of Angelenos, one of the City’s key strategies is to increase the local water supply and decrease the need to purchase imported water. However, in large part due to urbanization, the majority of precipitation that falls onto the City flows into storm drains and out to the ocean. In light of these conditions, stormwater is an increasingly viable supply. Capturing and using stormwater on-site can offset potable water demand. Capturing and infiltrating stormwater into subsurface groundwater aquifers increases local groundwater reserves. Both infiltration and capture for direct use enhance the reliability of the City’s water supply. Projects to capture and conserve stormwater runoff comprise an important component of the City’s water supply portfolio. The City is a part of a complex multi-jurisdictional region. As such, implementing effective and comprehensive local stormwater capture projects involves a collaborative effort between several agencies including LADWP, the Los Angeles County Flood Control District (LACFCD), the Los Angeles Bureau of Sanitation (LASAN), the Los Angeles Bureau of Street Services (LABSS), the Los Angeles Bureau of Engineering (LABOE), and the US Army Corps of Engineers (USACE). Additionally, LADWP partners with many community-based organizations to leverage their relationships with the residents of the City. Working together on projects that have multi-benefits for multiple agencies allows for the opportunity to cost-share and reduces the financial burden.

Land Subsidence and Aquifer-System Compaction in the San Jacinto Valley, Riverside County, California

U.S. Geological Survey (USGS) | January 1st, 1976