The Radical Groundwater Storage Test

Scientific American | October 19th, 2017

IN BRIEF California could better survive flood years and drought years by capturing floodwaters and using them to recharge underground aquifers that farmers and muni

IN BRIEF California could better survive flood years and drought years by capturing floodwaters and using them to recharge underground aquifers that farmers and municipalities now pump from when rains are scarce. To do so, water users and managers have to regard surface water and groundwater as one connected resource. A variety of test projects are proving that this approach can work. For example, farm fields can be flooded even when crops are growing so the water can percolate down into aquifers. Revising water rights and paying landowners to allow flooding can help the techniques work across California and the world.

The Rainfall Intensity-Duration Control of Debris Flows After Wildfire

American Geophysical Union (AGU) | May 23rd, 2023

The Reasonable Use Doctrine and Water Use Efficiency Report

Publisher not available | April 5th, 2011

The purpose of the report is to review the breadth of the Reasonable Use Doctrine, which can affect all water uses, including urban, hydropower, recreation, environment,

The purpose of the report is to review the breadth of the Reasonable Use Doctrine, which can affect all water uses, including urban, hydropower, recreation, environment, and agriculture, and then to focus on how the Reasonable Use Doctrine can be used promote efficient use of water in the agricultural sector. The underlying premise of this report is that the inefficient use of water is an unreasonable use of water. Accordingly, the Reasonable Use Doctrine is available prospectively to prevent general practices of inefficient water use. Indeed, the Reasonable Use Doctrine, as set forth in the State Constitution and California Statutes is broad and inviolate in scope. As interpreted by case law and administrative decisions and used to its full potential, it can comprehensively address the inefficient use of water in California.

The Reasonable Use Doctrine in California Water Law and Policy

University of California College of the Law, San Francisco (UC Law SF) | August 30th, 2016

The cardinal principle of California water law is that all water rights, and all uses of water, must be reasonable. This seemingly simple and innocuous sentence masks a w

The cardinal principle of California water law is that all water rights, and all uses of water, must be reasonable. This seemingly simple and innocuous sentence masks a world of meaning and complexity, however, because the requirement of reasonable use embraces at least four interrelated concepts. The determination of reasonable water use is utilitarian: the law seeks to encourage relatively efficient, economically and socially beneficial uses of the state’s water resources. It is situational: the evaluation of individual reasonable use concerns not only the water right holder’s own uses but also other competing demands (both consumptive and ecological) on the water resource. The reasonable use doctrine is also dynamic: the definition of reasonable use varies as the economy, technology, demographics, hydrologic conditions, environment, and societal needs evolve. And, because all uses of water must be consistent with this interdependent and variable definition of reasonable use, the law renders all water rights fragile. A water right that was reasonable when first recognized, and which may have been exercised reasonably for many years, may become unreasonable as hydrologic conditions change, as California’s economy evolves, as population grows and new demands for water arise, as ecological needs are better understood, and as the environmental laws that protect the state’s aquatic ecosystems and native species are applied in ways that limit the impoundment and diversion of water for consumptive uses.

The Rebirth of California Fish & Game Code Section 5937: Water for Fish

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

Swarms of living creatures will live wherever the river flows. There will be large numbers of fish, because this water flows there and makes the salt water fresh; so wh

Swarms of living creatures will live wherever the river flows. There will be large numbers of fish, because this water flows there and makes the salt water fresh; so where the river flows everything will live. Fishermen will stand along the shore; from En Gedi to En Eglaim there will be places for spreading nets. In an average year, California receives inflows and imports of water totaling around 200 million acre-feet,2 enough water to cover the entire state twenty-three inches deep. But California is a state of spatial and temporal water extremes. Spatially, precipitation varies wildly: Death Valley in the Southeast averages less than three inches per year, yet the northwestern corner of the state averages over 140 inches per year. More than 70% of California’s stream flow originates north of Sacramento, but more than 80% of the water is used south of Sacramento. Temporally, precipitation varies both seasonally and annually. California’s wet season typically runs from October or November to April or May, with little or no precipitation during the growing season, from May to September.7 Annual rainfalls of 40% or more below average and 36% or more above average each typically occur once every six to seven years.  To balance these extremes, over 1,300 dams store water across the state, supplying water for urban, industrial, and agricultural uses. While these uses sustain a tremendous part of California’s economy, they also come at high, often unappreciated costs. Fish also need water, so dams that alter water flows for human benefits may also have marked negative impacts on fish.

The reduced net carbon uptake over Northern Hemisphere land causes the close-to-normal CO2 growth rate in 2021 La Niña

American Association for the Advancement of Science (AAAS) | June 7th, 2024

The Regional Monitoring Program for Water Quality in San Francisco Bay, California, USA: Science in support of managing water quality

Regional Studies in Marine Science (Elsevier) | October 22nd, 2015

The Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) is a novel partnership between regulatory agencies and the regulated community to provide the

The Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) is a novel partnership between regulatory agencies and the regulated community to provide the scientific foundation to manage water quality in the largest Pacific estuary in the Americas. The RMP monitors water quality, sediment quality and bioaccumulation of priority pollutants in fish, bivalves and birds. To improve monitoring measurements or the interpretation of data, the RMP also regularly funds special studies. The success of the RMP stems from collaborative governance, clear objectives, and long-term institutional and monetary commitments. Over the past 22 years, high quality data and special studies from the RMP have guided dozens of important decisions about Bay water quality management. Moreover, the governing structure and the collaborative nature of the RMP have created an environment that allowed it to stay relevant as new issues emerged. With diverse participation, a foundation in scientific principles and a continual commitment to adaptation, the RMP is a model water qualitymonitoring program. This paper describes the characteristics of the RMP that have allowed it to grow and adapt over two decades and some of the ways in which it has influenced water quality management decisions for this important ecosystem.

The Relationship between California Rainfall and ENSO Events

American Meteorological Society (AMS) | November 1st, 1989

This paper examines the annual rainfall over California during 11 ENSO events within the period 1950 to 1982. During six of these, unusually wet conditions prevailed thro

This paper examines the annual rainfall over California during 11 ENSO events within the period 1950 to 1982. During six of these, unusually wet conditions prevailed throughout California; conditions were near normal during five events; and in one extreme drought occurred statewide. A comparison with the ENSO classification scheme of Fu et al, based on SST patterns in the Pacific, shows an excellent correspondence. Type 1 years, with large positive temperature anomalies east of the date line and lasting well into winter, are invariably events that enhance California rainfall. Normal years coincide with Type 2 ENSO events (moderate warming over a broad sector); the dry year is the sole Type 3 year, with weak anomalies confined to the eastern Pacific. This study also shows that the response to ENSO is regionally specific. Although throughout the state most years with extremely wet conditions are ENSO years, the tendency for an ENSO event to increase rainfall is greatest in Southern California, where 9 of 11 events produced above-normal rainfall and 8 of the 10 wettest years was an ENSO year. The pattern is more complex in central California; there ENSO years are almost invariably ones with highly abnormal rainfall, but they may be either wet or dry. The areas least influenced by ENSO are the Sierra Nevada and Northern California. The reasons for the geographical pattern of response become apparent when the seasonality and causes of rainfall in the various regions are evaluated.

The relative contributions of summer and cool-season precipitation to groundwater recharge, Spring Mountains, Nevada, USA

Hydrogeology Journal (Springer) | June 1st, 1998

A comparison of the stable-isotope signatures of spring waters, snow, snowmelt, summer (July thru September) rain, and cool season (October thru June) rain indicates that

A comparison of the stable-isotope signatures of spring waters, snow, snowmelt, summer (July thru September) rain, and cool season (October thru June) rain indicates that the high-intensity, short-duration summer convective storms, which contribute approximately a third of the annual precipitation to the Spring Mountains, provide only a small fraction (perhaps 10%) of the recharge to this major upland in southern Nevada, USA. Late spring snowmelt is the principal means of recharging the fractured Paleozoic-age carbonate rocks comprising the central and highest portion of the Spring Mountains. Daily discharge measurements at Peak Spring Canyon Creek during the period 1978–94 show that snowpacks were greatly enhanced during El Niño events.

The Resilience Value of Recycled Water for Los Angeles

University of California, Los Angeles (UCLA) | November 13th, 2024

In 2019, the City of Los Angeles (City) announced the development of the Operation NEXT Water Supply Program (Operation NEXT or Program) (City of Los Angeles, 2019), an a

In 2019, the City of Los Angeles (City) announced the development of the Operation NEXT Water Supply Program (Operation NEXT or Program) (City of Los Angeles, 2019), an advanced water recycling project aimed at expanding the use of purified recycled water. The current approach for Operation NEXT (now Pure Water Los Angeles) encompasses several distinct water infrastructure components. One is the construction and operation of an advanced water treatment purification facility at the Hyperion Wastewater Treatment Plant, the largest wastewater treatment facility west of the Mississippi. This project, in partnership with Los Angeles Sanitation & Environment comprises the Hyperion 2035 Program (Hyperion 2035) (LADWP, 2024; LASAN, 2024). Once constructed, potable recycled water flows from this facility will further diversify the City’s water supply portfolio, adding up to 257,636 acre-feet of supply each year once it is fully operational. A second component of Operation NEXT is a conveyance system that will transport this purified recycled water to groundwater basins or further treatment facilities, where it will be stored or blended with other water supplies. Currently, the construction and operation of Operation NEXT is still being estimated, and costs range between $6.4 billion and $24.0 billion USD as of 2020.