Colorado River

Draft Final Groundwater Sustainability Plan for the Borrego Springs Groundwater Subbasin

Borrego Water District (BWD) | August 30th, 2019

The Borrego Valley Groundwater Sustainability Agency (GSA, Agency), which comprises the Borrego Water District (BWD) and the County of San Diego (County), developed a Gro

The Borrego Valley Groundwater Sustainability Agency (GSA, Agency), which comprises the Borrego Water District (BWD) and the County of San Diego (County), developed a Groundwater Sustainability Plan (GSP, Plan) to provide a structure to enable local government, groundwater users and the local community to work together to achieve sustainable use of groundwater resources in the Borrego Springs Groundwater Subbasin (Subbasin) (California Department of Water Resources (DWR) Basin No. 7.024.01) of the Borrego Valley Groundwater Basin. The GSP was subsequently repurposed as a Groundwater Management Plan (GMP), an integral part of a Physical Solution in a groundwater rights adjudication consistent with the requirements of the Sustainable Groundwater Management Act (SGMA). The purpose of this GMP is to refine and expedite implementation of the Physical Solution and to avoid litigation over the GSP and its associated Project and Management Actions (PMAs). The GSP and this resulting GMP was developed through a process of stakeholder negotiation among major water users, landowners and government agencies. Specifically, this GMP is adopted as part of the Physical Solution by means of a Judgment. The Judgment was agreed to by Stipulating Parties accounting for more than 75% of groundwater production and more than 50% of non-minimal producer well owners as an alternative to the GSA/GSP process for the Borrego Springs Subbasin under SGMA (California Water Code Sections 10733.6 and 10737.4). This GMP includes and is to be interpreted and implemented consistent with and subject to the provisions of the Judgment. The provisions of the Judgment control over and supersede any contrary provisions contained in this GMP. Due to size, this file has been divided. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6

Drinking Water Notification Levels and Response Levels: An Overview

California State Water Resources Control Board (SWRCB) | February 6th, 2020

The Division of Drinking Water’s precursor, the Drinking Water Program of the California Department of Public Health (CDPH), and earlier, the California Department of H

The Division of Drinking Water’s precursor, the Drinking Water Program of the California Department of Public Health (CDPH), and earlier, the California Department of Health Services, CDHS, established health-based advisory levels, called “notification levels” (referred to as “action levels" through 2004), as needed since the early 1980s. These have been used to provide information to public water systems and others about certain non-regulated chemicals in drinking water that lack maximum contaminant levels (MCLs).  When chemicals are found at concentrations greater than these levels, certain requirement and recommendations apply.  Generally, notification levels have been established in response to actual contamination of drinking water supplies, e.g., perchlorate, which now has an MCL. However, notification levels for a number of chemicals were established in anticipation of possible contamination, such as from a hazardous waste site containing many pesticides (in the 1980s), or from a Superfund site (in the 2000s).  Chemicals for which notification levels are established may eventually be regulated by MCLs (through a formal regulatory process), depending on the extent of contamination, the levels observed, and the risk to human health. Most, however, have not proceeded to MCLs. Once established, a notification level generally stays in place, unless it is replaced by an MCL.On occasion, though, we have revised the numeric value of an individualnotification level to reflect new risk assessment information on the particularchemical. For some of the chemicals that had advisory levels established early on, if noMCL was adopted and the need for the notification level had passed, the advisory levelwas archived. Archived advisory levels may nevertheless be updated to reflect any newrisk information that may become available, and may be used as notification levels ifneeded. To date, of the 93 chemicals for which notification levels have been established; 40 now have MCLs. Of the remaining 53 chemicals, 29 are chemicals with current notification levels. 24 are chemicals with archived advisory levels (AALs). Note that following adoption of an MCL, the notification level is no longer used. For more about AALs and notification levels, go to: http://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/NotificationLevels.shtml. 

Drought less predictable under declining future snowpack

Nature Portfolio (Springer Nature) | April 20th, 2020

Mountain snowpack serves as an immense natural water reservoir, and knowledge of snow conditions helps predict seasonal water availability and offers critical ear

Mountain snowpack serves as an immense natural water reservoir, and knowledge of snow conditions helps predict seasonal water availability and offers critical early warning of hydrologic drought. This paradigm faces an impending challenge given consensus that a smaller fraction of future precipitation will fall as snow. Here, we apply downscaled hydrologic simulations from 28 climate model projections to show that by mid-century (2036–2065), 69% of historically snowmelt-dominated areas of the western United States see a decline in the ability of snow to predict seasonal drought, increasing to 83% by late century (2070–2099). Reduced predictability arises when peak snowpack approaches zero or because of decreased warm-season runoff efficiency. Changes in drought prediction skill show significant (P < 0.01) elevation dependence, with lower-elevation coastal areas most impacted by warming. Ancillary predictive information can only partially mitigate snow-based predictability losses to 65% of areas, underscoring the importance of declining future snowpack.

Drought Management and Climate Adaptation of Small, Self-Sufficient Drinking Water Systems in California

California Energy Commission (CEC) | August 15th, 2018

Examining human impacts, responses, and challenges to extreme climatic events can give insight into needed directions for climate adaptation to reduce future risks. This

Examining human impacts, responses, and challenges to extreme climatic events can give insight into needed directions for climate adaptation to reduce future risks. This study focuses on the 2012-2016 Drought in California, documenting how small self-sufficient drinking water systems were affected and challenged by, and responded to the extreme event.

Droughts in California

Public Policy Institute of California (PPIC) | April 1st, 2021

Economic Analysis of the 2014 Drought for California Agriculture

University of California, Davis (UC Davis) | July 15th, 2014

California is enduring its third driest year on record as agricultural, urban and environmental demands for water are at an all-time high. This report presents an assessm

California is enduring its third driest year on record as agricultural, urban and environmental demands for water are at an all-time high. This report presents an assessment of the economic impacts of the 2014 drought on crop production, livestock and dairies using a suite of models.  This analysis extends the preliminary estimates of the Central Valley drought impacts released May 19, 2014 (Howitt et al. 2014) to include:  •Broadened coverage of the Statewide Agricultural Production Model (SWAP) to include majoragricultural areas on California's central and south coasts and inland farms of the Imperial,Coachella and Palo Verde valleys, •Updated SWAP agricultural production and economic impact estimates for the Central Valleyusing the most current data available, •Estimated Central Valley impacts if the drought persists through 2015 and 2016, includingeconomic effects and the impact of increasing groundwater depletion and pumping depths usingthe California Department of Water Resources’ (DWR) C2VSIM model, •Estimated fallowing of cropland due to drought using the SWAP model, •Estimated losses to dairies and livestock using a supply elasticity approach based on pasturelosses and feed crop prices, and •Comments on the preliminary draft from various state agencies. The study finds that the 2014 drought will result in a 6.6 million acre-foot reduction in surface water available to agriculture. This loss of surface water will be partially replaced by increasing groundwater pumping by 5 million acre-feet.  The resulting net water shortage of 1.6 million acre-feet will cause losses of $810 million in crop revenue and $203 million in dairy and other livestock value, plus additional groundwater pumping costs of $454 million. These direct costs to agriculture total $1.5 billion. The total statewide economic cost of the 2014 drought is $2.2 billion, with a total loss of 17,100 seasonal and part-time jobs. Table ES-1 summarizes the key findings of the study. 

Economic Analysis of the 2015 Drought for California Agriculture

University of California, Davis (UC Davis) | August 17th, 2015

In 2015 California agriculture is facing its fourth year of severe drought. As in 2014, irrigation districts and farmers are showing more resilience to the drough

In 2015 California agriculture is facing its fourth year of severe drought. As in 2014, irrigation districts and farmers are showing more resilience to the drought than many had anticipated. Groundwater substitution has again greatly reduced crop fallowing and job losses. Water trading and operational flexibility also have significantly reduced the costs of the drought, and preservation of the most valuable crops has helped buffer economic impacts. However, the effects of drought are unevenly distributed over regions. In some regions with limited groundwater reserves the economic and employment impacts are very severe. In others, there is an increased cost of expanded groundwater use which is partially offset by high crop prices. Just as the economic impacts of the drought have grown modestly since 2014, continuation of the drought to 2016 or beyond with similar intensity is likely to slowlyerode the state’s agricultural production and employment.

Economic Impacts of the 2020–22 Drought on California Agriculture

University of California, Merced (UC Merced) | November 22nd, 2022

California just ended its third consecutive year of drought, resulting in the driest three-year period in the instrumental record. Multi-year deficits in precipitation in

California just ended its third consecutive year of drought, resulting in the driest three-year period in the instrumental record. Multi-year deficits in precipitation in the state’s usually wetter northern regions have been compounded by increased crop evaporative demands, leading to water scarcity impacts to agriculture across the state. Although 2020 was a dry year, water reserves stored during the wetter years of 2017 and 2019 greatly diminished drought impacts during that year. The water outlook changed rapidly in 2021—the third driest water year on record with the highest evaporative demand. The northern regions of the state—including the Sacramento Valley, the Scott and Shasta valleys, the Pit River valleys (northern intermountain valleys), and the Russian River—faced unusually dry conditions. Drought emergency conditions in 2021 were proclaimed first in the Russian River, Scott River and Shasta River basins, which faced subsequent curtailments. Water curtailments were extended to the Sacramento Valley later in the season. Water for local agriculture, ecosystems, exports, and water quality protection in the Sacramento-San Joaquin Delta were compromised by low water reserves. Atmospheric rivers in October and December 2021 provided temporary drought relief for a portion of the state, but record low precipitation from January-September allowed for extreme drought conditions to reign into the 2022 water year. To overcome persistent precipitation deficits and below-average storage in major reservoirs, the state again implemented water rights curtailments and low water deliveries from the State Water Project. The US Bureau of Reclamation announced reduced Central Valley Project deliveries—including unprecedented cutbacks to senior contractors in the Sacramento Valley—and local agencies implemented cutbacks as a first tier of drought response measures. Compared with the 2021 water year, however, 2022 brought less severe water cutbacks in the San Joaquin Valley. This report provides estimates of the economic impacts to agriculture for first three years of the current drought, which began in 2020. We use a combination of climate, hydrologic, agricultural and economic models, supplemented by informal surveys of irrigation districts and remote sensing data. The study includes nearly 88% of the 8.7 million acres of irrigated crop area in the state (LandIQ, 2019) excluding idle land. Our preliminary analysis for 2020–21 (Medellín-Azuara et al. 2022), focused on the Central Valley, and also examined the Russian River basin (North Coast), and northern intermountain valleys in Siskiyou, Shasta, and Modoc counties. Here, we expanded our spatial coverage to include the Central Coast, South Coast, and Colorado River.

Economics of a State Water Resources Program

Legislative Analyst's Office (LAO) | July 9th, 1957

Effective at Any Scale: Watershed-based Decision Support Tools

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

EcoAtlas  tools apply the USEPA’s three-level wetland monitoring and assessment framework for wetland and stream protection in a variety of California watersheds, an

EcoAtlas  tools apply the USEPA’s three-level wetland monitoring and assessment framework for wetland and stream protection in a variety of California watersheds, and it can be adjusted to more generally support natural resource planning, assessment, monitoring, and reporting. EcoAtlas operationalizes the Wetland and Riparian Area Monitoring Plan (WRAMP) by enabling users to assess the abundance, distribution, diversity, and condition of wetlands in the landscape or watershed context.