How are Western water districts managing groundwater basins?

California Agriculture (UCANR) | March 13th, 2018

Making the transition from open-access groundwater rights to sustainable groundwater management is a formidable task for newly formed groundwater sustainability age

Making the transition from open-access groundwater rights to sustainable groundwater management is a formidable task for newly formed groundwater sustainability agencies in California. As agencies begin to decide how to make equitable water allocations, how to monitor groundwater use and what mix of supply- and demand-side mechanisms to adopt to satisfy sustainability criteria, the groundwater management strategies in place across other basins in the western United States are worth studying. We surveyed 18 groundwater districts in California and other Western states to identify the management approaches and practices they have instituted. The conclusions we draw suggest a correlative rights framework of water allocation with phase-ins for heavy users; metered pumping; flexible arrangements for trading and carrying over allocations for multiple years; and incentivizing groundwater recharge, including recharge from deep percolation from crops. Rigid formulas for significantly reducing groundwater use in medium- and high-priority basins are likely to have significant negative effects on the regional economy.

Human viral nucleic acids concentrations in wastewater solids from Central and Coastal California USA

Nature Portfolio (Springer Nature) | June 22nd, 2023

Hydraulic, Geochemical, and Thermal Monitoring of an Aquifer System in the Vicinity of Mammoth Lakes, Mono County, California, 2015–17

U.S. Geological Survey (USGS) | June 27th, 2019

Since 2014, the U.S. Geological Survey has been working in cooperation with the Bureau of Land Management, Mono County, Ormat Technologies, Inc., and the Mammoth Communit

Since 2014, the U.S. Geological Survey has been working in cooperation with the Bureau of Land Management, Mono County, Ormat Technologies, Inc., and the Mammoth Community Water District to design and implement a groundwater-monitoring program for the proposed Casa Diablo IV Geothermal Power Project in Long Valley Caldera, California, to characterize baseline groundwater-level, water-temperature, and water-chemistry conditions at dedicated monitoring wells and municipal supply wells. The publicly available data and the analyses provided here represent quality-assured and peer-reviewed information to help with the management of the thermal and non-thermal water resources beneath and in the vicinity of the town of Mammoth Lakes, California. The methods of data collection for continuous water levels and quarterly water-temperature profiles for two 600-foot-deep monitoring wells during 2016 through 2017 are discussed. Also discussed are the methods of water-sample collection and characterizations of the water chemistry in numerous wells in the multilayered aquifer system beneath Mammoth Lakes. Additionally, the methodology used to develop digital (mathematical) filters to remove or reduce the effects of barometric pressure and solid Earth tides on the continuous water-level records is discussed. Digitally filtered water levels for a 2017 flow test of a deep geothermal production well are described, and various aquifer responses observed during the flow test are discussed. These are further considered in a companion evaluation of potential physical and chemical influences on the water-level data collected during the flow test. The digitally filtered water-level data indicated that some hydraulic communication exists between the deep geothermal aquifer and shallow groundwater aquifer at the location of the flow test, northeast of Mammoth Lakes. Groundwater-chemistry data from three wells indicated that shallow groundwater naturally mixes with a small component of geothermal water along the northern periphery of the shallow aquifer system at Mammoth Lakes.

Hydrologic Modeling of the Santa Clara River Watershed with the U.S. EPA Hydrologic Simulation Program - FORTRAN (HSPF)

Ventura County Watershed Protection District | January 24th, 2009

The purpose of the Santa Clara River (SCR) Watershed Feasibility Study as described in the PMP (October, 2003) is to determine the impact of the upstream urbanization, s

The purpose of the Santa Clara River (SCR) Watershed Feasibility Study as described in the PMP (October, 2003) is to determine the impact of the upstream urbanization, specifically in Los Angeles County, to the present natural state of the river in Ventura County and communities adjacent to the River that expect to develop close to the river banks. It is the goal of the watershed study to develop the necessary baseline data and analytical tools. In order to evaluate these impacts the feasibility study will include: • A comprehensive update of hydrologic, hydraulic, and sediment (yield and transport) models for a range of flow rates for existing conditions and future conditions within the Santa Clara River. The hydrologic model provides the flow data needed as input to the hydraulic and sediment transport models. • The hydrologic model will also be used to evaluate baseline and changes to water quality and pollutant loadings as a result of development or any proposed regional solutions to flooding or water quality problems. • Generate computer models that can simulate the impacts of land use changes under existing, natural and future conditions, and provide data to forecast the resulting changes to streamflow in the Santa Clara River. • Existing conditions include recently installed flood control and water supply/storage facilities. For future conditions, the modeling will include proposed land use changes, any additional flood control or sediment control facilities, and the effects of changes in sediment flow to the downstream areas as a result of proposed alternatives to mitigate flooding or water quality problems. The Natural Condition will be modeled by assuming the watershed has not been developed or subjected to extensive ranching or agricultural activities (pre-European). This document is the Final Report for the watershed hydrology model of the Santa Clara River Watershed using the U.S. EPA Hydrologic Simulation Program FORTRAN (HSPF). This effort was funded directly and wholly by contract with the Ventura County Watershed Protection District (VCWPD). This report identifies and describes the watershed characteristics and types of data required/available for the model, the segmentation of the watershed for modeling purposes, model calibration and validation efforts, and the results for the Baseline and Natural Conditions Scenario model runs. This effort has been designed to produce a comprehensive watershed model that meets the needs of the hydrologic model component of the SCR Watershed Feasibility Study as described above. This model was designed to: a. Represent hydrologic conditions throughout the SCR watershed for a wide range of flow conditions continuously for both high flows, low flows and individual storm events b. Provide continuous flow boundary conditions for the hydraulic and sediment transport models, at the appropriate spatial scales and boundary locations identified by the Feasibility Study participants c. Provide a modeling framework for subsequent sediment yield and water quality modeling requirements of the Feasibility Study d. Include a long-term database of 40 or more years of model input (e.g. precipitation, evaporation, diversions, POTWs) to allow long-term model simulations needed to develop the required flood (and low flow) frequency information at selected points throughout the SCR Watershed e. Provide long-term model simulations for both Baseline (current) and Natural Condition alternatives as a basis for assessing and comparing with planned Future Condition alternatives.

Hyperspectral characterization of wastewater in the Tijuana River Estuary using laboratory, field, and EMIT satellite spectroscopy

Elsevier | May 8th, 2025

Hundreds of millions of liters of untreated wastewater are discharged into the Tijuana River annually, impacting communities on both sides of the US-Mexico border. Curren

Hundreds of millions of liters of untreated wastewater are discharged into the Tijuana River annually, impacting communities on both sides of the US-Mexico border. Current monitoring methods are resource-intensive and limited in coverage. Optical satellite imaging may enable broader spatiotemporal monitoring, yet retrievals of bacterial concentrations and other key water quality indicators remain challenging. Here we investigate the utility of spectroscopic sensors to monitor the presence of wastewater in this estuarine-coastal system, as a proxy for bacterial concentrations and other water quality parameters. We prepared dilutions of untreated wastewater and uncontaminated seawater, measuring visible through shortwave infrared (VSWIR; 350–2500 nm) reflectance spectra of each sample. At high wastewater concentrations, a distinct spectral feature centered near 620 nm strongly correlated with paired water quality measurements (R2 ≥ 0.97, p-value < 0.01). This feature is additionally observed in multispectral resolution, in field observations, and in hyperspectral satellite imagery. An example application of plume mapping with this feature is presented, representing one of the earliest adoptions of EMIT hyperspectral satellite imagery for water quality monitoring. These results are promising for the use of spectroscopic sensors to map and monitor wastewater pollution in the Tijuana River Estuary and potentially, similarly polluted coastal and estuarine systems.

Identification of Bacteria in Groundwater Used for Domestic Supply in the Southeast San Joaquin Valley, California, 2014

U.S. Geological Survey (USGS) | June 22nd, 2021

Groundwater is an important source of drinking water in California. Water-borne diseases caused by microbial contamination are a growing concern. The MI test, a membrane

Groundwater is an important source of drinking water in California. Water-borne diseases caused by microbial contamination are a growing concern. The MI test, a membrane filtration method for the chromogenic-/-fluorogenic detection of total coliforms and Escherichia coli, was used for samples collected January to April 2014 from 42 domestic wells in the southeastern San Joaquin Valley. The wells were sampled as part of the Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP), a cooperative study between the U.S. Geological Survey and the California State Water Resources Control Board. Polymerase chain reaction analysis and sequencing of deoxyribonucleic acid (DNA) were used for 34 target and nontarget colonies that grew on the MI media from samples collected from 13 of the domestic wells to identify what genera of bacteria could exist in groundwater used by domestic wells. Gene sequences obtained using the Sanger method were entered into the basic local alignment search tool (BLAST) database, and 17 genera of bacteria were identified. Of these, 13 genera contain species that are human pathogens or opportunistic human pathogens. All the genera that include human pathogens are naturally present in soil, plants, or water; one of the pathogens also can be found in fecal matter. Six of the human pathogens were from non-target colony growth on the MI media. Target and non-target microbial growth on MI media are indicators of the possible presence of pathogenic bacteria even if the bacteria naturally are from soil rather than from a fecal source.

Identifying and Addressing Contaminant Sources Impacting an Urban Estuary

San Francisco Estuary Institute (SFEI) | July 1st, 2016

Identifying the location and population served by domestic wells in California

Journal of Hydrology: Regional Studies (Elsevier) | November 17th, 2014

Study region: California, USA. Study focus: Identification of groundwater use is an important stepin the regional-scale assessment of groundwater quality. In Califo

Study region: California, USA. Study focus: Identification of groundwater use is an important stepin the regional-scale assessment of groundwater quality. In California, 1990 US Census data indicate that domestic wells provide drinking-water to about 1.2 million people. However, the location of these domestic well users of groundwater is poorly identified because the census tracts can be quite large (up to 20,000 km2). The purposes of this paper are to present methods used for (1) estimating the location of domestic wells, (2) estimating the location of households using domes-tic well water; and (3) identifying where in California groundwater isan important source of domestic drinking supply.New hydrological insights for the region: Aggregating the results indicates that three hydrogeologic provinces contain nearly 80% of all domestic wells and also have the highest density of domestic well-users: Central Valley (31.6%), Sierra Nevada (31.5%), and NorthernCoast Ranges (16.6%). Results were also aggregated into groundwater basins and highland areas, collectively called Groundwater Units(GUs). Twenty-eight of the 938 GUs contain more than 50% of the total population served by domestic wells, 70 GUs contain more than 75%, and 150 GUs contain 90%. The 28 GUs are mostly located in the eastern and southern San Joaquin Valley (11), the Sacramento Valley (7), and the western foothills of the Sierra Nevada province (5). Using the information presented in this research along with other information about domestic-well use, the US Geological Survey has begun sampling high-use GUs for the Shallow Aquifer Assessment component of the Groundwater Ambient Assessment (GAMA) program.

Impacts of the 2014 severe drought on the Microcystis bloom in San Francisco Estuary

Harmful Algae (Elsevier) | February 17th, 2017

The increased frequency and intensity of drought with climate change may cause an increase in the magnitude and toxicity of freshwater cyanobacteria harmful algal blooms

The increased frequency and intensity of drought with climate change may cause an increase in the magnitude and toxicity of freshwater cyanobacteria harmful algal blooms (CHABs), including Microcystis blooms, in San Francisco Estuary, California. As the fourth driest year on record in San Francisco Estuary, the 2014 drought provided an opportunity to directly test the impact of severe drought on cyanobacteria blooms in SFE. A field sampling program was conducted between July and December 2014 to sample a suite of physical, chemical, and biological variables at 10 stations in the freshwater and brackish reaches of the estuary. The 2014 Microcystis bloom had the highest biomass and toxin concentration, earliest initiation, and the longest duration, since the blooms began in 1999. Median chlorophyll a concentration increased by 9 and 12 times over previous dry and wet years, respectively. Total microcystin concentration also exceeded that in previous dry and wet years by a factor of 11 and 65, respectively. Cell abundance determined by quantitative PCR indicated the bloom contained multiple potentially toxic cyanobacteria species, toxic Microcystis and relatively high total cyanobacteria abundance. The bloom was associated with extreme nutrient concentrations, including a 20-year high in soluble reactive phosphorus concentration and low to below detection levels of ammonium. Stable isotope analysis suggested the bloom varied with both inorganic and organic nutrient concentration, and used ammonium as the primary nitrogen source. Water temperature was a primary controlling factor for the bloom and was positively correlated with the increase in both total and toxic Microcystis abundance. In addition, the early initiation and persistence of warm water temperature coincided with the increased intensity and duration of the Microcystis bloom from the usual 3 to 4 months to 8 months. Long residence time was also a primary factor controlling the magnitude and persistence of the bloom, and was created by a 66% to 85% reduction in both the water inflow and diversion of water for agriculture during the summer. We concluded that severe drought conditions can lead to a significant increase in the abundance of Microcystis and other cyanobacteria, as well as their associated toxins.

Increases in Anthropogenic Gadolinium Anomalies and Rare Earth Element Concentrations in San Francisco Bay over a 20 Year Record

American Chemical Society (ACS) | January 7th, 2016

We evaluated both the spatial distribution of gadolinium (Gd) and other rare earth elements (REE) in surface waters collected in a transect of San Francisco Bay (SFB) a

We evaluated both the spatial distribution of gadolinium (Gd) and other rare earth elements (REE) in surface waters collected in a transect of San Francisco Bay (SFB) and their temporal variations within the Bay over two decades. The REE were preconcentrated using the NOBIAS PA-1 resin prior to analysis by high-resolution inductively coupled plasma mass spectrometry. Measurements revealed a temporal increase in the Gd anomaly in SFB from the early 1990s to the present. The highest Gd anomalies were observed in the southern reach of SFB, which is surrounded by several hospitals and research centers that use Gd-based contrast agents for magnetic resonance imaging. Recent increases in that usage presumably contributed to the order of magnitude increase in anthropogenic Gd concentrations in SFB, from 8.27 to 112 pmol kg−1 over the past two decades, and reach the northeast Pacific coastal waters. These measurements (i) show that “exotic” trace elements used in new high-tech applications, such as Gd, are emerging contaminants in San Francisco Bay and that anthropogenic Gd concentrations increased substantially over a 20 year period; (ii) substantiate proposals that REE may be used as tracers of wastewater discharges and hydrological processes; and (iii) suggest that new public policies and the development of more effective treatment technologies may be necessary to control sources and minimize future contamination by REE that are critical for the development of new technologies, which now overwhelm natural REE anomalies.