Chowchilla Subbasin Sustainable Groundwater Management Act (SGMA) Groundwater Sustainablity Plan

Chowchilla Subbasin GSP Advisory Committee | January 1st, 2020

Clean Water, Clean Beaches Water Quality Funding Measure*

Los Angeles County Department of Public Works (LACDPW) | September 21st, 2012

The Problem: Stormwater and runoff rushes down the street, picking up trash and toxic pollutants. On a rainy day, over 10 billion gallons of contaminated stormw

The Problem: Stormwater and runoff rushes down the street, picking up trash and toxic pollutants. On a rainy day, over 10 billion gallons of contaminated stormwater flows directly — untreated — into rivers, creeks, lakes and our bay and coastal waters. Polluted stormwater and urban runoff include toxins and pathogens that can affect our health, drinking water supplies, and the health of marine life. Contaminants include: Industrial solvents, paints and chemicals; heavy metals like lead, mercury, chromium and arsenic; infection-causing bacteria; pesticides and fertilizers; and trash like plastics, cigarette butts, candy wrappers and syringes. *The proposed solution, a parcel tax to fund stormwater remediation and capture projects, failed before the Los Angeles County Board of Supervisors in 2013.

Climate Action Plan

Metropolitan Water District of Southern California (MWD) | May 31st, 2022

The Metropolitan Water District of Southern California’s (Metropolitan) core mission is to provide a clean, reliable water supply to Southern California. Changing clim

The Metropolitan Water District of Southern California’s (Metropolitan) core mission is to provide a clean, reliable water supply to Southern California. Changing climatic conditions, variable precipitation patterns, availability of water supplies, changes in consumer demands, and sea level rise will change the way Metropolitan provides its services and how it operates its regional water system. Metropolitan recognizes the potential impact of climate change to water availability and is committed to environmental stewardship to protect this valuable resource. Reducing greenhouse gas (G H G) emissions is an important step in protecting California and the region from the effects of climate change. Reducing G H G emissions from Metropolitan’s operations supports California’s overall G H G reduction goals. This Climate Action Plan (CAP) sets targets for reducing G H G emissions from Metropolitan’s operations, including conveyance, storage, treatment, and delivery of water to its 26 member water agencies. Additionally, this CAP complements Metropolitan’s existing long-range planning efforts, including the Integrated Water Resources Plan, Energy Sustainability Plan, and Capital Investment Plan. Through the implementation of this CAP, Metropolitan will strengthen its commitment to environmental sustainability, increase the resiliency of its operations, and strategically achieve G H G reduction goals. For additional details on the purpose of this CAP and Metropolitan’s history and existing operations, refer to Section 1.0, Purpose, Overview, and Environmental History and Leadership.

Climate Action Plan, Phase 3: Climate Change Vulnerability Assessment

California Department of Water Resources (DWR) | February 14th, 2019

Climate change impacts have been widely documented globally, across the nation, and within the state. Loss of snowpack; longer, more frequent heat waves; and longer, more

Climate change impacts have been widely documented globally, across the nation, and within the state. Loss of snowpack; longer, more frequent heat waves; and longer, more intense wildfire seasons are already being experienced in California. While uncertainties remain about the exact timing and extent of projected impacts, numerous climate-driven hazards represent a clear threat to Department of Water Resources (DWR) facilities, managed lands, operations, and staff activities. By conducting this department-wide vulnerability assessment, DWR seeks to better prepare its decision-making for an uncertain future.  This climate change vulnerability assessment (VA) provides the first evaluation of its kind for facilities owned and operated by DWR and the activities that DWR performs. This analysis draws from the extensive body of knowledge about climate change and attempts to evaluate, describe, and quantify — where possible — DWR’s vulnerabilities to expected increases in wildfire, extreme heat, and sea-level rise, as well as to changes in hydrology and ecosystems that will impact DWR’s facilities, operations, and other activities. Table ES-1 presents examples of vulnerabilities identified in this assessment and summarizes quantitative indicators of climate change risk.  Using a mid-century time horizon, climate-change-driven hazards assessed in this VA are presented under six categories: wildfire, extreme heat, sea-level rise, long-term persistent hydrologic changes, short-term extreme hydrologic events, and habitat and ecosystem services degradation. This assessment applies a common framework to examine vulnerability through three components of how DWR’s assets and operations could be exposed to future climate hazards, how these assets and operations are sensitive (or susceptible) to impacts of this exposure, and the capacity of these assets and operations to cope with or adapt to changing conditions or events. 

Climate change decisive for Asia’s snow meltwater supply

Nature Portfolio (Springer Nature) | June 24th, 2021

Streamflow in high-mountain Asia is influenced by meltwater from snow and glaciers, and determining impacts of climate change on the region’s cryosphere is essential to

Streamflow in high-mountain Asia is influenced by meltwater from snow and glaciers, and determining impacts of climate change on the region’s cryosphere is essential to understand future water supply. Past and future changes in seasonal snow are of particular interest, as specifics at the scale of the full region are largely unknown. Here we combine models with observations to show that regional snowmelt is a more important contributor to streamflow than glacier melt, that snowmelt magnitude and timing changed considerably during 1979–2019 and that future snow meltwater supply may decrease drastically. The expected changes are strongly dependent on the degree of climate change, however, and large variations exist among river basins. The projected response of snowmelt to climate change indicates that to sustain the important seasonal buffering role of the snowpacks in high-mountain Asia, it is imperative to limit future climate change.

Climate change intensification of horizontal water vapor transport in CMIP5

American Geophysical Union (AGU) | July 8th, 2015

Global warming of the Earth’s atmosphere is hypothesized to lead to an intensification of the global water cycle. To determine associated hydrological changes, most pr

Global warming of the Earth’s atmosphere is hypothesized to lead to an intensification of the global water cycle. To determine associated hydrological changes, most previous research has used precipitation. This study, however, investigates projected changes to global atmospheric water vapor transport (integrated vapor transport (IVT)), the key link between water source and sink regions. Using22 global circulation models from the Climate Model Intercomparison Project Phase 5, we evaluate, globally, the mean, standard deviation, and the 95th percentiles of IVT from the historical simulations(1979–2005) and two emissions scenarios (2073–2099). Considering the more extreme emissions, multimodel mean IVT increases by 30–40% in the North Pacific and North Atlantic storm tracks and in the equatorial Pacific Ocean trade winds. An acceleration of the high-latitude IVT is also shown. Analysis of low-altitude moisture and winds suggests that these changes are mainly due to higher atmospheric water vapor content.

Climate change intensification of horizontal water vapor transport in CMIP5

American Geophysical Union (AGU) | June 8th, 2015

Global warming of the Earth’s atmosphere is hypothesized to lead to an intensification of the global water cycle. To determine associated hydrological changes, most pr

Global warming of the Earth’s atmosphere is hypothesized to lead to an intensification of the global water cycle. To determine associated hydrological changes, most previous research has used precipitation. This study, however, investigates projected changes to global atmospheric water vapor transport (integrated vapor transport (IVT)), the key link between water source and sink regions. Using 22 global circulation models from the Climate Model Intercomparison Project Phase 5, we evaluate, globally, the mean, standard deviation, and the 95th percentiles of IVT from the historical simulations (1979–2005) and two emissions scenarios (2073–2099). Considering the more extreme emissions, multimodel mean IVT increases by 30–40% in the North Pacific and North Atlantic storm tracks and in the equatorial Pacific Ocean trade winds. An acceleration of the high-latitude IVT is also shown. Analysis of low-altitude moisture and winds suggests that these changes are mainly due to higher atmospheric water vapor content.

Climate Change Risks Faced by the California Central Valley Water Resource System

California Energy Commission (CEC) | ?

Observed climate trends and projections of accelerated future change have motivated several studies of the impacts of climate change on water resources management in Cal

Observed climate trends and projections of accelerated future change have motivated several studies of the impacts of climate change on water resources management in California. This paper presents a methodology that improves on previous approaches, revealing fundamental climate change risks to one of the State of California’s key water resource systems — the integrated California Central Valley System (CCVS). By using a bottom-up decision scaling approach, starting with a systematic climate change stress test of the performance of the system to changes in temperature and precipitation, specific vulnerabilities to the system are identified. This study also improves on previous water resource vulnerability analyses by incorporating and evaluating a much wider range of inter-annual precipitation variability than has previously been used. By drawing from the 1,100-year (reconstructed dendrochronology) record of Sacramento and San Joaquin river flows, vulnerabilities to low frequency natural climate variability are analyzed in concert with expected potential climate changes. The results of this analysis provide a comprehensive summary of the sensitivity of the system to climate change. This paper provides results and discussion of select future system performance metrics at 2050. Results indicate that declines in almost every category (e.g., supply, storage, delta outflow) of system performance are likely. The likelihood of severely degraded future performance is especially high for north-of-Delta carryover storage and Delta exports. The results of this study are expected to provide water managers and decision-makers with more actionable science because they provide probabilistic results that can be used in more traditional risk management approaches to planning of climate change adaptation investment decisions.

Climate change-resilient snowpack estimation in the Western United States

Nature Portfolio (Springer Nature) | June 18th, 2024

Climate change, atmospheric rivers, and floods in California - a multimodel analysis of storm frequency and magnitude changes

American Water Resources Association (AWRA) | June 1st, 2011

Recent studies have documented the important role that “atmospheric rivers” (ARs) of concentrated near‐surface water vapor above the Pacific Ocean play in the storm

Recent studies have documented the important role that “atmospheric rivers” (ARs) of concentrated near‐surface water vapor above the Pacific Ocean play in the storms and floods in California, Oregon, and Washington. By delivering large masses of warm, moist air (sometimes directly from the Tropics), ARs establish conditions for the kinds of high snowlines and copious orographic rainfall that have caused the largest historical storms. In many California rivers, essentially all major historical floods have been associated with AR storms. As an example of the kinds of storm changes that may influence future flood frequencies, the occurrence of such storms in historical observations and in a 7‐model ensemble of historical‐climate and projected future climate simulations is evaluated. Under an A2 greenhouse‐gas emissions scenario (with emissions accelerating throughout the 21st Century), average AR statistics do not change much in most climate models; however, extremes change notably. Years with many AR episodes increase, ARs with higher‐than‐historical water‐vapor transport rates increase, and AR storm‐temperatures increase. Furthermore, the peak season within which most ARs occur is commonly projected to lengthen, extending the flood‐hazard season. All of these tendencies could increase opportunities for both more frequent and more severe floods in California under projected climate changes.