Central Coast

Recent decreases in snow water storage in western North America

Nature Portfolio (Springer Nature) | May 22nd, 2023

Mountain snowpacks act as natural water towers, storing winter precipitation until summer months when downstream water demand is greatest. We introduce a Snow Storage Ind

Mountain snowpacks act as natural water towers, storing winter precipitation until summer months when downstream water demand is greatest. We introduce a Snow Storage Index (SSI), representing the temporal phase difference between daily precipitation and surface water inputs—sum of rainfall and snowmelt into terrestrial systems—weighted by relative magnitudes. Different from snow water equivalent or snow fraction, the SSI represents the degree to which the snowpack delays the timing and magnitude of surface water inputs relative to precipitation, a fundamental component of how snow water storage influences the hydrologic cycle. In western North America, annual SSI has decreased (p 

Recent strengthening of eastern Pacific ENSO in the last millennium paleorecord

American Association for the Advancement of Science (AAAS) | August 27th, 2026

The Pacific El Niño–Southern Oscillation (ENSO) generates climate extremes that endanger ecosystems, infrastructure, and human well-being worldwide. The response of th

The Pacific El Niño–Southern Oscillation (ENSO) generates climate extremes that endanger ecosystems, infrastructure, and human well-being worldwide. The response of this system to climate warming is poorly constrained, due both to data scarcity and uncertainties in climate models. The geochemistry of Galápagos coral skeletons across the past millennium reveals a large recent increase in interannual variability of sea surface temperature in the eastern equatorial Pacific compared to existing paleorecords that exceeds simulated natural variability. This increase parallels rising global temperature and results from stronger El Niño events. Central Pacific coral data also show increased variability, although less distinctly than in the Galápagos. Our results provide long-term context for understanding ENSO variability trends, with troubling implications for climate extremes.

Recharge Area Identification, Utilization, and Protection Resource Management Strategy

California Department of Water Resources (DWR) | April 29th, 2024

This resource management strategy (RMS) advances water supply augmentation, resilience, and equity in California by providing summaries of the state of knowledge, applica

This resource management strategy (RMS) advances water supply augmentation, resilience, and equity in California by providing summaries of the state of knowledge, applications, and available information and resources on recharge area identification, utilization, and protection.

Recharge net metering (ReNeM) is a novel, cost-effective management strategy to incentivize groundwater recharge

Nature Portfolio (Springer Nature) | October 18th, 2023

Recharge Net Metering to Enhance Groundwater Sustainability

University of California, Berkeley (UC Berkeley) | April 2nd, 2018

Groundwater sustainability depends on balancing aquifer inflows and outflows. Extraction (pumping of groundwater, typically for human use) and recharge (inflow of

Groundwater sustainability depends on balancing aquifer inflows and outflows. Extraction (pumping of groundwater, typically for human use) and recharge (inflow of water to an aquifer from the land surface and streams) are central components of this water balance. Often, increasing demands for groundwater are exacer- bated by stresses on limited surface water supplies. Changes in land use and shifting climate can result in less infiltration of precipitation into the ground, reducing recharge. Increasing water scarcity has led to increased pumping, and in turn, unsustainable management of groundwater in many basins, resulting in depleted supplies, degraded water quality, and other impacts.

Recommendations to Address the Expansion of Seawater Intrusion in the Salinas Valley Groundwater Basin

Monterey County Water Resources Agency (MCWRA) | October 12th, 2017

This report provides a discussion of the current knowledge and related background information surrounding seawater intrusion pathways and potential impacts ther

This report provides a discussion of the current knowledge and related background information surrounding seawater intrusion pathways and potential impacts thereof on the Salinas Valley Groundwater Basin. This document also serves as a body of evidence to catalogue the findings used to support the recommendations presented herein. Staff is making six recommendations, with each focused on a component that influences, or could be impacted by, the advancement of seawater intrusion. The recommendations are being presented in an order that builds upon the foundational knowledge laid out in the background section of this report, rather than in an order of priority. Each recommendation can be implemented on its own or in concert with the others, and the relative importance of each will be discussed individually in this report. However, the recommendations have been conceptualized as a comprehensive solution that, along with continued operation of projects that have been constructed for the same purpose, have the strongest potential to ensure success in slowing or halting further seawater intrusion when implemented simultaneously.

Recommendations to the State Water Resources Control Board Pursuant to California Water Code Section 10609

California Department of Water Resources (DWR) | September 29th, 2022

The Department of Water Resources (DWR) is pleased to provide the following recommendations developed in response to the 2018 Legislation (Senate Bill 606 [Hertzberg] and

The Department of Water Resources (DWR) is pleased to provide the following recommendations developed in response to the 2018 Legislation (Senate Bill 606 [Hertzberg] and Assembly Bill 1668 [Friedman]) enacted in support of “Making Water Conservation a California Way of Life.” The Legislation included provisions for advancing urban water use efficiency through developing and implementing various water use efficiency standards, variances for unique uses of water, and commercial, industrial, and institutional (CII) performance measures, among other requirements. Full reports detailing our methods, technical analyses, studies, public input, and recommendations will follow. These recommendations for long-term urban water use efficiency reflect technical considerations, public input, and the imperative to continue California’s progress in urban efficient use of water for future generations. If adopted DWR's recommendations on outdoor residential and CII water use on landscapes with dedicated irrigation meters, combined with the indoor residential water use standard recommendations submitted to the Legislature jointly by DWR and State Water Resources Control Board (State Water Board), pursuant to Water Code 10609.4 (b)(1), would result in expected long-term water savings of approximately 450,000 acre-feet per year starting in 2030 – considering 2019 population and 2017-2019 water use data, the water savings are enough to supply about 1.6 million homes or 4.7 million residents for both indoor and outdoor annual water needs.

Record-Setting Ocean Warmth Continued in 2019

Advances in Atmospheric Sciences (Springer) | February 1st, 2020

Human-emitted greenhouse gases (GHGs) have resulted in a long-term and unequivocal warming of the planet (IPCC, 2019). More than 90% of the excess heat is stored within

Human-emitted greenhouse gases (GHGs) have resulted in a long-term and unequivocal warming of the planet (IPCC, 2019). More than 90% of the excess heat is stored within the world’s oceans, where it accumulates and causes increases in ocean temperature (Rhein et al., 2013; Abram et al., 2019). Because the oceans are the main repository of the Earth’s energy imbalance, measuring ocean heat content (OHC) is one of the best ways to quantify the rate of global warming (Trenberth et al., 2016; Von Schuckmann et al., 2016; Cheng et al., 2018). Following reports released in the previous two years (Cheng and Zhu, 2018; Cheng et al., 2019c), this article presents new OHC data for the year 2019. These data reveal that the world’s oceans (especially the upper 2000 m) in 2019 were the warmest in recorded human history. Specifically, the ocean heat anomaly (0−2000 m) in 2019 was 228 Zetta Joules (ZJ, 1 ZJ=1021 Joules) above the 1981−2010 average and 25 ZJ above 2018 (Table 1). The OHC values (for the upper 2000 m) were obtained from the Institute of Atmospheric Physics (IAP) ocean analysis (see “Data and methods” section, below), which uses a relatively new method to treat data sparseness and updates in the instruments that have been used to measure ocean temperature (Cheng et al., 2017). The evolution of OHC (Fig. 1) shows that the upper 2000 m OHC in 2019 was 228 ± 9 ZJ above the 1981–2010 average. The record-setting ocean warmth is also found in National Oceanic and Atmospheric Administration/National Center for Environmental Information (NOAA/NCEI) data, showing 217± 4 ZJ in 2019 above the 1981−2010 average (21 ZJ above 2018) (Table 1) (updated from Levitus et al. 2012). With these newly available IAP data, a ranking of the warmest years since the 1950s is now possible (Table 1). The past five years are the top five warmest years in the ocean historically with modern instruments, and the past ten years are also the top ten years on record. The same ranking also applies to NOAA/NCEI data (Table 1).

Recovery Plan for Tidal Marsh Ecosystems of Northern and Central California

U.S. Fish and Wildlife Service (FWS) | September 23rd, 2013

The Recovery Plan for Tidal Marsh Ecosystems of Northern and Central California features five endangered species: two endangered animals, California clapper rail (Rallus

The Recovery Plan for Tidal Marsh Ecosystems of Northern and Central California features five endangered species: two endangered animals, California clapper rail (Rallus longirostris obsoletus) and salt marsh harvest mouse (Reithrodontomys raviventris) and three endangered plants, Cirsium hydrophilum var. hydrophilum (Suisun thistle), Chloropyron molle ssp. molle (soft bird’s-beak), and Suaeda californica (California sea-blite). The biology of these species is at the core of the recovery plan, but the goal of this effort is the comprehensive restoration and management of tidal marsh1 ecosystems. This recovery plan is an expansion and revision of The California Clapper Rail and Salt Marsh Harvest Mouse Recovery Plan (U.S. Fish and Wildlife Service 1984). The historic distribution of the California clapper rail encompasses major tidal marshes between Humboldt Bay and Morro Bay, defining the approximate geographic scope of this recovery plan. In addition to the California clapper rail and the salt marsh harvest mouse, the plan also covers three focal listed plant species that were listed as federally endangered in the 1990s and the northernmost population of an additional plant species. Two of the species, Cirsium hydrophilum var. hydrophilum and Chloropyron molle ssp. molle (this species’ former name is Cordylanthus mollis ssp. mollis which is how it appears on the List of Threatened and Endangered Species, but we use the currently accepted name here), are restricted to the northern reaches of the San Francisco Bay Estuary. The other endangered tidal marsh plant, Suaeda californica, historically occurred in both San Francisco Bay and Morro Bay but, except for three reintroductions to San Francisco Bay, is now restricted to Morro Bay. Another federally listed plant, Chloropyron maritimum ssp. maritimum (salt marsh bird’s-beak; formerly Cordylanthus maritimus ssp. maritimus), has its northern range limit in Morro Bay. Morro Bay was omitted from the Salt Marsh Bird’s-beak Recovery Plan (U.S. Fish and Wildlife Service 1985a) because the taxonomic interpretation at the time classified this population in another subspecies that is not federally listed. Current taxonomic interpretation considers the Morro Bay population as Chloropyron maritimum ssp. maritimum. It is included in this recovery plan due to its co-location with Suaeda californica in Morro Bay. Though recovery strategies and actions are provided for the Morro Bay population of C. maritimum ssp. maritimum, recovery criteria are not, therefore, the species should not be considered covered by the recovery portion of the document. In addition, this recovery plan addresses 11 species or subspecies of concern. These include the salt marsh wandering shrew (Sorex vagrans halicoetes), Suisun shrew (Sorex ornatus sinuosus), San Pablo vole (Microtus californicus sanpabloensis), California black rail (Laterallus jamaicensis coturniculus), three song sparrow subspecies of the San Francisco Bay Estuary (Alameda song sparrow [Melospiza melodia ssp. pusillula], Suisun song sparrow [M.m. maxillaris] and San Pablo song sparrow [M.m. samuelis]), saltmarsh common yellowthroat (Geothlypis trichas sinuosa), old man tiger beetle (Cicindela senilis senilis), Lathryrus jepsonii ssp. jepsonii (delta tule pea), and Spartina foliosa (Pacific cordgrass). These species occur in a variety of tidal marsh habitats where they are limited by the requirements of moisture, salinity, topography, soil types, and climatic conditions. Adjacent uplands and ecotone areas are also crucial habitats for many of these species. Primary threats to all the listed species include historical and current habitat loss and fragmentation due to urban development, agriculture, and diking related to duck hunting; altered hydrology and salinity; non-native invasive species; inadequate regulatory mechanisms; disturbance; contamination; risk of extinction due to small population size; and the most central threat, sea level rise due to climate change.

Redefining expectations for urban water supply systems to fight wildfires

Springer Nature | March 5th, 2025

When considering massive new costs for urban water systems to fight wildfires, we also need to look hard at the distribution of benefits from these investments, and desig

When considering massive new costs for urban water systems to fight wildfires, we also need to look hard at the distribution of benefits from these investments, and design legal and fiscal cost recovery mechanisms that align with those benefits. In the service area for the Los Angeles Department of Water and Power, greatly expanding capacity for water supply and fire-flow for the highest-elevation areas of the city would be delivering a benefit to communities that are much wealthier, on average, than the rest of the city. There is danger of placing a burden on less-resourced households to pay for the protection of well-resourced households, which would compound existing and profound environmental inequities in the city.