North Lahontan

Water Available for Replenishment 2018

California Department of Water Resources (DWR) | April 12th, 2018

Water Quality Control Plan for the Lahontan region

Lahontan Regional Water Quality Control Board (LRWQCB) | December 15th, 2015

Water quality standards and control measures for surface and ground waters of the Lahontan Region are contained in the Water Quality Control Plan for the Lahontan Region

Water quality standards and control measures for surface and ground waters of the Lahontan Region are contained in the Water Quality Control Plan for the Lahontan Region (Basin Plan). The plan designates beneficial uses for water bodies and establishes water quality objectives, waste discharge prohibitions, and other implementation measures to protect those beneficial uses. State water quality standards also include a Nondegradation Policy. Water quality control measures include Total Maximum Daily Loads (TMDLs), which are often, but not always, adopted as Basin Plan amendments. See the Lahontan Water Board’s TMDL Program web page for further information. The Lahontan Basin plan took effect in 1995, replacing three earlier plans. The current edition of the plan includes fully approved sets of amendments adopted since 1995. Chapters and sections of the plan are available in separate files to facilitate downloading. In addition to the state standards in the Basin Plan, federal water quality standards for certain toxic pollutants apply to surface waters within California, including the Lahontan Region. These standards are contained in the National Toxics Rule (40 CFR 131.36) and the California Toxics Rule (40 CFR 131.37). The California State Water Resources Control Board (SWRCB) has adopted a statewide implementation policy for the federal toxics standards, including summary tables listing the standards themselves. The federal standards have not yet been physically incorporated into the Basin Plan. The National Toxics Rule and California Toxics Rule standards differ from federal water quality criteria in that they are enforceable. Federal criteria are non-enforceable, science-based thresholds that can be used in development of enforceable state water quality standards. For the latest information on this water quality control plan, including any amendments, click here.

Water quality for agriculture

Food and Agriculture Organization of the United Nations (FAO) | July 15th, 1985

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 Quality of Groundwater Used for Public Supply in Principal Aquifers of the Western United States

U.S. Geological Survey (USGS) | September 8th, 2020

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 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).