Review of Water Supply Reliability Estimation Related to the Sacramento-San Joaquin Delta

Delta Stewardship Council (Delta Council) | June 16th, 2022

Revised Groundwater Sustainability Plan County of Fresno GSA Management Area A & Management Area B Delta-Mendota Subbasin

County of Fresno | July 20th, 2022

The Delta-Mendota Subbasin (Basin 5-022.07 in the California Department of Water Resources (DWR) Bulletin 118) (Subbasin) is a high priority Subbasin that has been assign

The Delta-Mendota Subbasin (Basin 5-022.07 in the California Department of Water Resources (DWR) Bulletin 118) (Subbasin) is a high priority Subbasin that has been assigned a critical overdraft designation by DWR. The Subbasin consists of 24 Groundwater Sustainability Agencies (GSA) who together created six individual GSA groups, each preparing a GSP in a coordinated manner as required by SGMA. The County of Fresno elected to serve as the GSA for County areas within the Subbasin that are not included in other GSAs. The GSP group consists of two individual GSA’s Management Area A (MAA) and Management Area B (MAB) and are collectively referred to as Fresno County Management Areas (FCMA).

Revised Incidental Take Methodology for the Coordinated Long-Term Operation of the CVP and SWP

U.S. Fish and Wildlife Service (FWS) | January 30th, 2019

Revised Water Right Decision 1641

California State Water Resources Control Board (SWRCB) | December 29th, 1999

Revisiting chlorophyll a thresholds for San Francisco Bay: Insights from observations of phytoplankton molecular abundance

Elsevier | February 14th, 2026

Harmful Algal Blooms (HABs) are a hazard for coastal environments worldwide; identifying screening thresholds of chlorophyll-a (chl-a) associated with inc

Harmful Algal Blooms (HABs) are a hazard for coastal environments worldwide; identifying screening thresholds of chlorophyll-a (chl-a) associated with increased risk of HABs is a management priority. Molecular surveillance of coastal phytoplankton and bivalve biotoxins could be used to link chl-a with HAB risk, but requires an understanding of whether the HAB risks increase uniformly as chl-a rises, or whether some taxa are disproportionately favored, and if these relationships vary by season. In this study, we present a novel use of molecular abundance data to investigate the scientific bases for estuarine chl-a thresholds protective against HABs. In San Francisco Bay (SFB), California, the relationship between molecular relative abundance (as measured by 18S metabarcoding) of nine different HAB taxa, absolute quantitative polymerase chain reaction (qPCR) abundance, and mussel toxin concentrations of a subset of the taxa were investigated for thresholds as a function of increasing chl-a. Our results show most HAB taxa did not increase in absolute or relative abundance during SFB’s spring bloom interval, when chl-a levels were highest (>10 µg/L) but the assemblage was dominated by non-harmful diatoms. However, several flagellated, mixotrophic taxa did increase above their molecular baseline in fall, and the combined probability of any HAB occurring above baseline was elevated when chl-a reached ∼4.6 µg/L in the fall. This work demonstrates the promise of molecular approaches in disentangling the seasonally complex interplay between stressors and phytoplankton/HAB community responses and has the potential to provide clearer, more cost-effective monitoring and mitigation strategies for managers.

Reviving Central Valley Rivers

CALFED | June 1st, 2003

Ridging associated with drought in western and southwestern United States: characteristics, trends and predictability

American Meteorological Society (AMS) | April 1st, 2020

Persistent winter ridging events are a consistent feature of meteorological drought across the western and southwestern United States. In this study, a ridge detection al

Persistent winter ridging events are a consistent feature of meteorological drought across the western and southwestern United States. In this study, a ridge detection algorithm is developed and applied on daily geopotential height anomalies to track and quantify the diversity of individual ridge characteristics (e.g., position, frequency, magnitude, extent, and persistence). Three dominant ridge types are shown to play important, but differing, roles for influencing the location of landfalling atmospheric rivers (ARs), precipitation, and subsequently meteorological drought. For California, a combination of these ridge types is important for influencing precipitation deficits on daily through seasonal time scales, indicating the various pathways by which ridging can induce drought. Furthermore, both the frequency of ridge types and reduced AR activity are necessary features for explaining drought variability on seasonal time scales across the western and southwestern regions. The three ridge types are found to be associated in different ways with various remote drivers and modes of variability, highlighting possible sources of subseasonal-to-seasonal (S2S) predictability. A comparison between ridge types shows that anomalously large and persistent ridging events relate to different Rossby wave trains across the Pacific with different preferential upstream locations of tropical heating. For the “South-ridge” type, centered over the Southwest, a positive trend is found in both the frequency and persistence of these events across recent decades, likely contributing to observed regional drying. These results illustrate the utility of feature tracking for characterizing a wider range of ridging features that collectively influence precipitation deficits and drought.

RipZET: Documentation of Tool Demonstration in Marin County

San Francisco Estuary Institute (SFEI) | March 31st, 2015

The San Francisco Estuary Institute and Aquatic Science Center (SFEI‐ASC) has developed the Riparian Zone Estimation Tool (RipZET) to help the California community of

The San Francisco Estuary Institute and Aquatic Science Center (SFEI‐ASC) has developed the Riparian Zone Estimation Tool (RipZET) to help the California community of riparian interests visualize and characterize riparian areas as habitat unto themselves as well as their capacity to function as buffers for protecting the ecosystem services of the state’s streams, lakes and wetlands. RipZET is a tool used with Geographic Information System (GIS) and spreadsheet software to estimate “functional riparian width,” or the width associated with different riparian functions (e.g., large woody debris input, shading, floodwater storage), which varies with channel type and watershed location. The concept of functional riparian width is central to the riparian definition recommended by the National Research Council (NRC 2002) and is integral in many recently developed riparian design and management guidelines around the country.

Rise of Water Power in Electrical Supply

Scientific American | March 28th, 1903

Water power is destined to operate the greater part of electrical supply and street railways in North America. A large beginning in this direction has already been mad

Water power is destined to operate the greater part of electrical supply and street railways in North America. A large beginning in this direction has already been made. Electrical l oads are being transferred to water power faster than they are created and steam plants reduced to occasional use. Meantime development of the vast resources of water power on this continent is only in its initial stage.

Rising Seas and Electricity Infrastructure: Potential Impacts and Adaptation Actions for San Diego Gas & Electric

California Energy Commission (CEC) | August 31st, 2018

Part A: Rising sea levels pose a threat to California’s energy infrastructure and the coastal communities that it serves. To better understand this threat, this

Part A: Rising sea levels pose a threat to California’s energy infrastructure and the coastal communities that it serves. To better understand this threat, this study analyzed the exposure of San Diego Gas & Electric Company (SDG&E) electricity assets in San Diego County to climate change- driven coastal wave flooding, tidal inundation, and coastal erosion. The study found that the greatest potential direct impacts are damage to four substations in the Mission Bay and San Diego Bay areas. By modeling the potential costs to customers from unserved energy due to service disruptions driven by exposed substations, this study found economic impacts could— under an extreme sea level rise scenario in the late 21st century compounded by a 100 year storm-- range from $1.2 billion to $25 billion, assuming no adaptation actions are taken. Nearby communities could also experience indirect impacts if critical customers served by the substations—such as sewage pumping stations, hospitals, airports, and ports—are affected by outages. For other asset types, potential direct impacts are expected in the form of increased maintenance and repair costs. The research team identified a range of potential adaptation measures to build resilience to potential impacts. The application of flexible adaptation pathways emerged through the study as the best approach to improve implementation of these measures in the face of future uncertainty. Rather than selecting adaptation measures based only on what is known today, flexible adaptation pathways help establish information that that should be tracked, termed signposts, to help navigate uncertainty, set thresholds that trigger adaptation actions, and determine if an adaptation plan is meeting its objectives. Using these pathways, four initial climate adaptation actions were identified for SDG&E: 1) enhance coastal storm prediction and response, 2) identify signposts and thresholds that indicate when the need for an adaptation decision is approaching, 3) conduct consultations with regional stakeholders to identify opportunities to improve community-wide resilience, and 4) improve and fine-tune cost-benefit analysis methods to increase accuracy and confidence in cost-benefit estimates that incorporate climate change. Click here for Part B of the report, Potential Climate Change Impacts and Adaptation Actions for Gas Assets in the San Diego Gas and Electric Company Service Area, CEC, 2018