Gage Gap

Nature Conservancy | October 31st, 2018

Following a difficult five-year drought, California just had one of the wettest winters on record. The state is famous for its highly engineered water system, whi

Following a difficult five-year drought, California just had one of the wettest winters on record. The state is famous for its highly engineered water system, which moves millions of gallons of water from north to south and east to west. Thirty-nine million people and our $47 billion agricultural industry rely on that water, not to mention wildlife from the Sierra to the sea. And yet we have surprisingly little data about how much water is moving through our streams at any given time. There are over 3,600 locations in California where stream gages have been active at some point, but only 54% have been active recently. And even fewer of those provide the kind of rich, real-time reporting needed to manage what is arguably our state’s most precious and contentious resource.

Gaps and opportunities in nitrogen pollution policies around the world

Nature Portfolio (Springer Nature) | July 6th, 2020

Nitrogen pollution is an important environmental issue gaining traction in policy circles. However, there is little understanding of current nitrogen policies around the

Nitrogen pollution is an important environmental issue gaining traction in policy circles. However, there is little understanding of current nitrogen policies around the world: whether they account for nitrogen’s unique ability to exacerbate multiple environmental impacts or balance nitrogen’s dual role as an essential agricultural input and major pollutant. Here we assemble and analyse the first database of nitrogen policies generated by national and regional legislatures and government agencies, a collection of 2,726 policies across 186 countries derived from the ECOLEX database. The database covers all major environmental sinks (such as air, water and climate), economic sectors (including agriculture, wastewater and industry) and policy instruments (from market mechanisms to regulatory standards). We find that sink-centred policies are focused predominantly on water, mirroring the distribution of nitrogen’s global environmental and human health costs. However, policy integration across sinks is severely lacking, which heightens the risk of substituting one form of nitrogen pollution for another. Moreover, two-thirds of agricultural policies (ranging from broad sectoral programmes to nitrogen-specific measures) incentivize nitrogen use or manage its commerce, demonstrating the primacy of food production over environmental concerns.

Gates and Barriers in the Delta

Publisher not available | April 8th, 2013

While previous Delta Watermaster reports have dealt mainly with water rights and water supply issues, Water Code section 85230 (d) specifies that reports shall also be su

While previous Delta Watermaster reports have dealt mainly with water rights and water supply issues, Water Code section 85230 (d) specifies that reports shall also be submitted on water quality issues and conveyance operations. The use of barriers and gates in the Delta addresses both of these topics.

Gauging climate preparedness to inform adaptation needs: local level adaptation in drinking water quality in CA, USA

Climatic Change (Springer) | December 23rd, 2013

Understanding resource managers’ perceptions of climate change, analytic capacity, and current adaptation activities can provide insight into what can help support ada

Understanding resource managers’ perceptions of climate change, analytic capacity, and current adaptation activities can provide insight into what can help support adaptation processes at the local level. In California, where a major drought currently demonstrates some of the hardships that could be regularly encountered under a changing climate, we present results from a survey of drinking water utilities about the perceived threat, analytic capacity, and adaptation actions related to maintaining water quality in the face of climate change. Among surveyed utilities (n = 259), awareness is high in regard to climate change occurring and its potential impacts on water quality globally, but perceived risk is lower with regard to climate impacts on local drinking water quality. Just over half of surveyed utilities report at least some adaptation activity to date. The top three variables that most strongly correlated with reported adaptation action were (1) perceived risk on global and local water quality, (2) surface water reliance, and (3) provision of other services beyond drinking water. Other tested variables significantly correlated with reported adaptation action were (4) degree of impact from the current drought and (5) communication with climate change experts. Findings highlight that smaller groundwater-reliant utilities may need the most assistance to initiate climate adaptation processes. Trusted information sources most frequently used across respondents were state government agencies, followed by colleagues in the same utilities. The finding that frequently used sources of information are similar across utilities presents a promising opportunity for training and disseminating climate information to assist those systems needing the most support.

Generalized Streamflow Relations of the San Bernardino and Eastern San Gabriel Mountains, California

U.S. Geological Survey (USGS) | October 19th, 1972

Geochemistry and isotope hydrology of representative aquifers in the Great Basin region of Nevada, Utah, and adjacent States

U.S. Geological Survey (USGS) | July 1st, 1996

Geochemistry of Ground Water in the Sacramento Valley, California

U.S. Geological Survey (USGS) | July 13th, 1984

A geochemical investigation was done to evaluate temporal changes in water quality and to determine the processes that control water chemistry in shallow ground water of

A geochemical investigation was done to evaluate temporal changes in water quality and to determine the processes that control water chemistry in shallow ground water of the Sacramento Valley, California. A total of 671 chemical analyses from 651 wells were used to study the processes controlling water chemistry. Temporal variations in dissolved-solids and nitrate concentrations were studied in 140 and 62 wells, respectively, having multiple observations with time.

Geohydrologic and Water-Quality Data in the Vicinity of the Rialto-Colton Fault, San Bernardino, California

U.S. Geological Survey (USGS) | July 7th, 2014

The Rialto-Colton Basin is in western San Bernardino County, about 60 miles east of Los Angeles, California. The basin is bounded by faults on the northeast and southwest

The Rialto-Colton Basin is in western San Bernardino County, about 60 miles east of Los Angeles, California. The basin is bounded by faults on the northeast and southwest sides and contains multiple barriers to groundwater flow. The structural geology of the basin leads to complex hydrology. Between 2001 and 2008, in an effort to better understand the complex hydrologic system of the Rialto-Colton Basin, seven multiple-well monitoring sites were constructed. Two to six observation wells were installed in the borehole at each site; a total of 32 observation wells were installed. This report presents geologic, hydrologic, and water-quality data collected from these seven multiple-well monitoring sites. Descriptions of the collected drill cuttings were compiled into lithologic logs for each monitoring site. The lithologic logs are summarized along with the geophysical logs, including gamma-ray, spontaneous potential, resistivity, and electromagnetic induction tool logs. At selected sites, sonic tool logs also were recorded. Periodic water-level measurements are reported, and water-level data are displayed on hydrographs. Water levels at multiple-well monitoring sites in the northern part of the study area differed between the shallow and deep observation wells; in the remaining multiple-well monitoring sites, water levels differed little with depth. Along the southern trace of the Rialto-Colton Fault, water levels are slightly higher east of the fault than west of the fault. Selected water-quality data for 21 of the observation wells show water from wells in the northern and central parts of the study area is calcium-carbonate water. In the southern part of the study area, water from wells screened above 400 feet below land surface is of mixed type or is calcium-carbonate water. Water from wells screened greater than 400 feet below land surface in the southern part of the study area is sodium-carbonate or sodium-mixed anion water. Water from most wells in the study area plots above the Global Meteoric Water Line along an apparent local meteoric water line, indicating the water has not experienced substantial evaporation before infiltration. A few samples from shallow wells in the study area plot slightly to the right of the Global Meteoric Water Line, possibly indicating the water experienced some evaporation before recharge.

Geohydrologic Framework of Recharge and Seawater Intrusion in the Pajaro Valley

U.S. Geological Survey (USGS) | July 17th, 2003

The Pajaro Valley Water Management Agency (PVWMA) was established in 1984 by the State of California as the agency charged with ground-water management in Pajaro Valley (

The Pajaro Valley Water Management Agency (PVWMA) was established in 1984 by the State of California as the agency charged with ground-water management in Pajaro Valley (figs. 1A, B). The PVWMA must deal with issues of both water supply and water quality. Managing water resources for agricultural and municipal users requires maintaining a reliable water supply to meet growing demands while preventing ground-water overdraft and the related degradation of water quality. Important regional water-quality concerns include increased nitrate concentrations and seawater intrusion. To protect the quantity and quality of the ground-water supplies, the PVWMA has implemented a plan to prevent further seawater intrusion. In order to evaluate how these activities can be conducted most effectively, it is necessary to improve the understanding of the hydrogeology and geochemistry of the water resources in the Pajaro Valley.

Geohydrological Characterization, Water-Chemistry, and Ground-Water Flow Simulation Model of the Sonoma Valley Area, Sonoma County, California

U.S. Geological Survey (USGS) | December 14th, 2006

Sonoma County is in the northern part of the greater San Francisco Bay region, an area of Northern California that has experienced rapid population growth and accelerated

Sonoma County is in the northern part of the greater San Francisco Bay region, an area of Northern California that has experienced rapid population growth and accelerated urbanization in response to economic expansion over the past few decades. The large increase in population and concomitant changes in land use within Sonoma County require reassessment of the water resources and how best to manage them for optimal utilization over the next few decades. Most basins in the county currently rely on a combination of Russian River water and native ground water to meet demand. Recycled water is used on a limited basis. In addition, water conservation programs have been implemented and are being expanded. The Sonoma Valley is a well-defined hydrologic basin in southeastern Sonoma County. The basin has some areas of declining ground-water levels, potential water-quality problems from seawater intrusion and upwelling of geothermal waters, and ground-water/surface-water interaction. Location of the Study Area The study area is located approximately 30 miles (mi) northeast of San Francisco and includes the entire Sonoma Creek watershed in southeastern Sonoma County, California (fig. 1). The study focused on the area of the valley floor and the adjacent hills where most of the urban development and irrigated agriculture have been occurring. The watershed includes approximately 166 square miles (mi2) of land that drains by way of Sonoma Creek and its tributaries to San Pablo Bay (fig. 2), which is the northern arm of the San Francisco Bay. The Sonoma Mountains form the southwestern side of the watershed and the Mayacmas Mountains form the northeastern side. Between these two mountain ranges lies the northwest trending elongate depression of Sonoma Valley, which extends roughly 20 mi from the shore of San Pablo Bay to near Kenwood (fig. 2). Purpose and Scope: The U.S. Geological Survey (USGS), in cooperation with the Sonoma County Water Agency (SCWA), undertook this study to evaluate the ground-water resources of Sonoma Valley and to develop a tool to better understand and manage the ground-water system. The goals of the study were to update the geohydrologic characterization of the study area; to provide a current assessment of hydrologic conditions, including a description of historical ground-water level and waterquality changes; and to provide water-supply agencies with a ground-water flow model that can be used as a planning tool for water-resources assessment and management. To meet the objectives of this study, four principal tasks were identified: (1) evaluation of existing geohydrologic, geophysical, and geochemical data; (2) collection and analysis of new geohydrologic data, including subsurface lithologic data, gravity measurements, ground-water levels, and streamflow gains and losses; (3) collection and analysis of new water chemistry, temperature, and isotopic data; and (4) development a ground-water flow model. This report provides a geologic and hydrologic description of the area, presents selected hydrologic data collected from the 1970s to 2004, quantifies historical changes in the ground-water system, documents a ground-water flow simulation model, and presents an interpretation of surface geophysical data that help define the geometry of the ground-water reservoir.