North Coast

Water Quality in Basin-Fill Aquifers of the Southwestern United States: Arizona, California, Colorado, Nevada, New Mexico, and Utah, 1993–2009

U.S. Geological Survey (USGS) | July 15th, 2014

Water Resources Data for California, Water year 1983, Volume 2, Pacific Slope Basins from Arroyo Grande to Oregon State Line except Central Valley

U.S. Geological Survey (USGS) | January 15th, 1985

Water resources data for the 1983 water year for California consists of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservo

Water resources data for the 1983 water year for California consists of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 2 contains discharge records for 145 gaging stations; stage and contents for 19 lakes and reservoirs; water quality for 17 stations; water levels for 67 observation wells. Also included are 2 low-flow partial-record stations and 18 water-quality partial-record stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.

Water Right Exactions

Social Science Research Network (SSRN) | May 15th, 2023

Water shortages worsened by reservoir effects

Nature Portfolio (Springer Nature) | November 13th, 2018

The expansion of reservoirs to cope with droughts and water shortages is hotly debated in many places around the world. We argue that there are two counterintuiti

The expansion of reservoirs to cope with droughts and water shortages is hotly debated in many places around the world. We argue that there are two counterintuitive dynamics that should be considered in this debate: supply–demand cycles and reservoir effects. Supply–demand cycles describe instances where increasing water supply enables higher water demand, which can quickly offset the initial benefits of reservoirs. Reservoir effects refer to cases where over-reliance on reservoirs increases vulnerability, and therefore increases the potential damage caused by droughts. Here we illustrate these counterintuitive dynamics with global and local examples, and discuss policy and research implications.

Water Supply in the Conterminous United States, Alaska, Hawaii, and Puerto Rico, Water Years 2010–20, Chapter B of U.S. Geological Survey Integrated Water Availability Assessment—2010–20

U.S. Geological Survey (USGS) | January 17th, 2025

The following are the key points of this chapter: Throughout much of the Great Plains and Northeast through Midwest aggregated hydrologic regions, low precipitation

The following are the key points of this chapter: Throughout much of the Great Plains and Northeast through Midwest aggregated hydrologic regions, low precipitation totals in water years 2011 and 2012 resulted in low streamflow, evapotranspiration, and soil moisture, associated with one of the most substantial droughts since the 1930s. The highest interannual variability in precipitation was in the California–Nevada, Texas, Southern High Plains, and Southwest Desert hydrologic regions, whereas the lowest interannual variability was in the Florida, Tennessee–Missouri, and Northeast hydrologic regions. Among the Western aggregated hydrologic region, where snow is critical for water availability, the California–Nevada hydrologic region had the highest interannual variability in maximum snow accumulation with a coefficient of variation (CV) of 0.60, whereas the Columbia–Snake, Pacific Northwest, and Central Rockies hydrologic regions all had a CV of less than 0.36. Six of 29 unconfined and 6 of 23 confined principal and regional aquifer systems had current water-level percentiles (median 2010–20) of less than 30 percent of historical water levels (that is, median 2000–20 water levels) including the California Coastal Basin aquifers, the Colorado Plateaus aquifers, and the Central and Southern regions of the High Plains aquifer. Hydrologic regions with low precipitation and little storage coincide with aquifer systems that have shown a decline in groundwater levels during water years 2010–20, including the Southern High Plains, Central High Plains, and Texas hydrologic regions. Companion chapters: U.S. Geological Survey Integrated Water Availability Assessment—2010–20, Chapter A Status of Water-Quality Conditions in the United States, 2010–20, Chapter C  Water Use Across the Conterminous United States, Water Years 2010–20, Chapter D  Climate Change and Future Water Availability in the United States, Chapter E  Integrated Water Availability in the Conterminous United States, 2010–20, Chapter F 

Water Use in California

Public Policy Institute of California (PPIC) | April 19th, 2023

Water Year 2017: What a Difference a Year Makes

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

The very wet conditions of 2017 gave many parts of the state access to excess surface waters for both planned and impromptu groundwater recharge, and fall 2017 groundwate

The very wet conditions of 2017 gave many parts of the state access to excess surface waters for both planned and impromptu groundwater recharge, and fall 2017 groundwater level data (not available until the end of the calendar year) should show the effects of the substantial recharge water available

Water Year 2021 Compound Precipitation and Temperature Extremes in California and Nevada

American Meteorological Society (AMS) | December 23rd, 2022

The most intense 22-yr drought in the western United States since 800 CE (Williams et al. 2022) was extended by compound dry and hot extremes in Water Year 2021 (October

The most intense 22-yr drought in the western United States since 800 CE (Williams et al. 2022) was extended by compound dry and hot extremes in Water Year 2021 (October 2020–September 2021). Compared to an instrumental record that dates to 1895, low precipitation (Fig. 1a) and high temperatures (Fig. 1b) were widespread across the western United States. The intense and prevalent drought has caused water delivery shortages (U.S. Bureau of Reclamation 2021), damaged ecosystems (Wlostowski et al. 2022), and contributed to extreme wildfires (e.g., Fu et al. 2021; Gutierrez et al. 2021; Abolafia-Rosenzweig et al. 2022). California and Nevada (CA–NV) were once again at the epicenter of drought and heat in Water Year 2021 (California Department of Water Resources 2021). This was the first time since 1895 that precipitation fell below –1.5 standardized departures and temperatures exceeded 1.5 standardized departures concurrently for the two-state average (Fig. 1c). Precipitation and temperatures were individually extreme as well, as the former was the second lowest since 1895 and the latter was the second highest. We examine whether the co-occurrence of anthropogenic climate change and La Niña, two principal climate drivers during Water Year 2021, altered the risk of unprecedented compound dry and hot extremes in CA–NV during Water Year 2021. Our assessment investigates the factors related to compound extremes that lead to heightened societal impacts compared to individual extreme events (e.g., AghaKouchak et al. 2020; Zscheischler et al. 2020; W. Zhang et al. 2021).

Waterline responses to climate forcing along the North American West Coast

Nature Portfolio (Springer Nature) | June 7th, 2025

Understanding waterline variability at seasonal to interannual timescales is crucial for predicting coastal responses to climate forcing. However, relationships between l

Understanding waterline variability at seasonal to interannual timescales is crucial for predicting coastal responses to climate forcing. However, relationships between large-scale climate variability and coastal morphodynamics remain underexplored beyond intensively monitored sites. This study leverages a newly developed 25-year (1997–2022) satellite-derived waterline dataset along the North American West Coast. Our results reveal distinct latitudinal patterns in seasonal waterline change, with excursions exceeding 25 m in the Pacific Northwest, decreasing to less than 10 m in Southern California and farther south. Waterline fluctuations strongly follow wave power in the Pacific Northwest (R = −0.78), northern California (R = −0.75), and Baja California (R = −0.62), while Baja California Sur aligns more with sea-level variations (R = −0.42). Interannually, waterline change exhibits latitudinal dependence: south of southern California, variability is low, with major erosion confined to strong El Niño-Southern Oscillation (ENSO) events, while northern regions show mixed responses. ENSO-driven storm track shifts modulate winter wave climate, resulting in enhanced (attenuated) erosion from southern California to Baja California Sur during El Niño (La Niña). However, further north, ENSO impacts are less consistent, reflecting a complex interplay of storm track displacement and intensification. These findings highlight the spatial complexity of ENSO-driven morphodynamics and provide a framework for assessing climate-induced coastal vulnerability.

Watershed Condition, Turbidity, and Implications for Anadromous Salmonids in North Coastal California Streams

California State Water Resources Control Board (SWRCB) | May 21st, 2008

It is widely acknowledged that historically intensive human disturbances increased erosion and sediment delivery rates to extreme levels in the 1950s through the 1970s ac

It is widely acknowledged that historically intensive human disturbances increased erosion and sediment delivery rates to extreme levels in the 1950s through the 1970s across the north coast, and are likely continuing to affect turbidity durations to some degree. A more controversial question is to what extent contemporary land use is affecting present-day erosion, sediment delivery and turbidity. Using turbidity exceedence levels to indicate watershed disturbance, we approached this question from several perspectives. Part A of this report follows up and expands on an earlier analysis (Klein, 2003) for which turbidity data sets from only eight sites were available. In the present study, annual turbidity data sets were assembled from up to 28 continuous turbidity and stage recording stations located on small streams in the northcoast region from Del Norte County in the north to Mendocino County in the south. Data spanning three water years (WY2003-2005) were processed to calculate lengths of time turbidity was higher than several thresholds. Turbidity thresholds ranged from 25 (frequently cited in the salmonid literature as causing ill effects when exceeded) to 1000 FNU. Turbidity exceedence analyses, similar to conventional flow exceedence analyses, were also performed, allowing comparison of turbidity levels at various exceedence probabilities. Part B of this report uses turbidity relationships to harvest rate to model potential effects on anadromous salmonids within a cumulative watershed effects (CWE) framework. To evaluate CWEs on anadromous salmonids and the stream ecosystem, annual turbidigraphs were produced from WY1991 through WY2005 at annual average harvest rates of 0% to 6% for an 8 mi2 old second-growth watershed in North Coastal California. The turbidigraphs were very conservative in that they used the ‘Lower Bound Lines’ to estimate turbidity from discharge, rather than a line of best fit. Turbidity thresholds established at 10, 25, and 50 FNU were applied to assess chronic background, moderate, and severe stress to stream ecosystems in each water year. A simple model of smolt growth and survival-to-adult-return (SAR), as influenced by the annual turbidigraph, indicated the minimum supportable adult steelhead population size could be more than halved at the 2% average annual timber harvest rate compared to that supported by an old second-growth watershed.