California Fish and Game, Volume 6

California Fish and Game Commission | January 1st, 1920

California Fish and Game, Volume 69

California Department of Fish and Wildlife (CDFW) | July 1st, 1963

California forest die-off linked to multi-year deep soil drying in 2012–2015 drought

Nature Portfolio (Springer Nature) | July 1st, 2019

Widespread episodes of recent forest die-off have been tied to the occurrence of anomalously warm droughts, although the underlying mechanisms remain inadequately

Widespread episodes of recent forest die-off have been tied to the occurrence of anomalously warm droughts, although the underlying mechanisms remain inadequately understood. California’s 2012–2015 drought, with exceptionally low precipitation and warmth, and widespread conifer death, provides an opportunity to explore the chain of events leading to forest die-off. Here, we present the spatial and temporal patterns of die-off and moisture deficit during California’s drought, based on field and remote sensing observations. We found that die-off was closely tied to multi-year deep-rooting-zone drying, and that this relationship provides a framework with which to diagnose and predict mortality. Marked tree death in an intensively studied Sierra Nevada forest followed a four-year moisture overdraft, with cumulative 2012–2015 evapotranspiration exceeding precipitation by ~1,500 mm, and subsurface moisture exhaustion to 5–15-m depth. Observations across the entire Sierra Nevada further linked tree death to deep drying, with die-off and moisture overdraft covarying across latitude and elevation. Unusually dense vegetation and warm temperatures accelerated southern Sierran evapotranspiration in 2012–2015, intensifying overdraft and compounding die-off by an estimated 55%. Climate change is expected to further amplify evapotranspiration and moisture overdraft during drought, potentially increasing Sierran tree death during drought by ~15–20% °C−1.

California Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project: Domestic-Supply Assessment

U.S. Geological Survey (USGS) | March 14th, 2024

California Groundwater Conditions Update – Spring 2019

California Department of Water Resources (DWR) | October 3rd, 2022

DWR has completed an evaluation of state-wide groundwater level data reported in spring 2019 for California groundwater basins. Spring data correspond to the time period

DWR has completed an evaluation of state-wide groundwater level data reported in spring 2019 for California groundwater basins. Spring data correspond to the time period immediately before the typical irrigation season begins in a region. This helps show groundwater levels before summer crop irrigation and other uses. In Central and Northern California, the pre-irrigation season is in March, while in Southern California, that season is typically earlier. The Spring 2019 Groundwater Level Data Coverage map (Figure 1) shows a comparison between total spring 2019 reporting and typical reporting in previous years. Typical reporting includes wells with water level data submitted to DWR over the past five spring seasons (2015-2019) by CASGEM Monitoring Entities, other local agencies, and well owners. Although the reporting percentage is high and coverage is good, there are still gaps in spring 2019 coverage throughout the state, including portions of Tulare, Kern, San Bernardino, Riverside, and Imperial counties.

California Groundwater Conditions Update – Spring 2020

California Department of Water Resources (DWR) | October 3rd, 2022

In this report, groundwater level change values compare spring 2020 to spring 2019, 2017, 2015, and 2010. The information is summarized in Table 1. Spring groundwater lev

In this report, groundwater level change values compare spring 2020 to spring 2019, 2017, 2015, and 2010. The information is summarized in Table 1. Spring groundwater level data are an important indicator of groundwater conditions because spring generally corresponds to the pre-irrigation season. This time period is representative of the water year’s peak groundwater levels. Associated maps display groundwater level increases and decreases and summarize data by hydrologic region.

California Groundwater Conditions Update – Spring 2021 California’s drought and groundwater

California Department of Water Resources (DWR) | October 3rd, 2022

This report uses maps to depict how groundwater levels have changed over time using two different analytical methods. One method, groundwater level change maps, show the

This report uses maps to depict how groundwater levels have changed over time using two different analytical methods. One method, groundwater level change maps, show the change in groundwater levels between two different springtime measurements. The second method uses trend analysis of water levels for wells having at least 10 annual springtime measurements over a 20-year period to illustrate the statistical magnitude and direction of groundwater level change (a well’s water level increasing or decreasing trend over time). Spring groundwater level data are an important indicator of groundwater conditions because spring generally corresponds to both the pre-irrigation season and the peak groundwater levels in a water year.

California Groundwater Units

U.S. Geological Survey (USGS) | June 5th, 2014

The California Groundwater Units dataset classifies and delineates areas within the State of California into one of three groundwater-based polygon units: (1) those areas

The California Groundwater Units dataset classifies and delineates areas within the State of California into one of three groundwater-based polygon units: (1) those areas previously defined as alluvial groundwater basins or subbasins, (2) highland areas that are adjacent to and topographically upgradient of groundwater basins, and (3) highland areas not associated with a groundwater basin, only a hydrogeologic province. In total, 938 Groundwater Units are represented. The Groundwater Units dataset relates existing groundwater basins with their newly delineated highland areas which can be used in subsequent hydrologic studies. The methods used to delineate groundwater-basin-associated highland areas are similar to those used to delineate a contributing area (such as for a lake or water body); the difference is that highland areas are constrained to the immediately surrounding upslope (upstream) area. Upslope basins have their own delineated highland. A geoprocessing tool was created to facilitate delineation of highland areas for groundwater basins and subbasins and is available for download.

California Hydraulic Mining under the Caminetti Act

Scientific American | July 21st, 1900

The gold deposits of California are, for a large part, contained in gravel beds once the channel of rivers which formed the drainage of the west slope of th

The gold deposits of California are, for a large part, contained in gravel beds once the channel of rivers which formed the drainage of the west slope of the Sierra Nevada Mountains. In the course of ages new rivers were formed, leaving the ancient gravel beds elevated often hundreds of feet above the river beds of the present. The depth of the gravel in the old channels is often several hundred feet and the width across them frequently one-half mile, while their courses may be traced for thirty or forty miles in length in detached sections, which are the remnants of once continuous beds. Denudation and the cutting down of the present streams has removed parts of the ancient channels and they often disappear below the surface for several miles underneath coverings of lava which have been spread over them ...  Hydraulic mining became an immense industry. At the time when it had reached its greatest development it was estimated that more than one hundred millions of dollars had been invested in the construction of water supplies, mining plant, tunnels, and flumes, and more than two million dollars have been spent in the equipment of a single mine. Everything was upon an immense scale, and the amounts of gravel removed were in proportion. So large, in fact, that the material washed into the streams caused blockages over spreading agricultural lands in the Sacramento Valley, obstructing and raising the beds of the navigable rivers which enter San Francisco Bay, causing inundations at times of flood, and generally making its influence noticeable 200 miles from the seat of mining. In 1880 it was estimated that in the bed of the Yuba River alone there were stored more than one hundred and forty million cubic yards of accumulations, and the bed of the river had spread over a width of two and one-half miles between the side levees built to confine the spread of the deposits.

California Hydrogeologically Vulnerable Areas Map

California State Water Resources Control Board (SWRCB) | January 31st, 2012

In response to Executive Order D-5-99, State Water Board staff created a map where published hydrogeologic information indicates soil or rock conditions that may be more

In response to Executive Order D-5-99, State Water Board staff created a map where published hydrogeologic information indicates soil or rock conditions that may be more vulnerable (or susceptible) to groundwater contamination: ”Hydrogeologically Vulnerable Areas.” The map was created due to groundwater concerns over releases of MTBE, primarily from leaking underground storage tank sites. However, areas that are vulnerable to MTBE may also be vulnerable to other contaminants released at the surface. The map was created in 2000 using Department of Water Resources (DWR) and US Geological Survey publications. Data from these publications were used to identify areas where geologic conditions are more likely to allow recharge at rates substantially higher than in lower permeability or confined areas of the same groundwater basin. The identified areas are associated by a metadata table (in the following pages) which identifies (1) DWR basin name and number, (2) published source of information (i.e., title, date, author, and appropriate page, figure, table, or plate number), and (3) specific criteria upon which the vulnerability category is based. Groundwater resources underlying designated (i.e., published) recharge, rapid infiltration, or unconfined areas were considered categorically more vulnerable to potential contaminant releases than groundwater underlying areas of slower recharge, lower infiltration rates, or intervening low permeability deposits (i.e., confining layers).