Workshop on Delta Outflows and Related Stressors Panel Summary Report

Delta Stewardship Council (Delta Council) | May 15th, 2014

This report was prepared as part of the State Water Resources Control Board’s (“Board”) process of developing and implementing updates to the Bay-Delta Plan and flo

This report was prepared as part of the State Water Resources Control Board’s (“Board”) process of developing and implementing updates to the Bay-Delta Plan and flow objectives to protect beneficial uses in the Bay-Delta Watershed. The focus of this report is Delta outflows and related stressors. The report is based upon reading extensive background materials selected by the Delta Science Program as well as materials identified by individual Panel members to be relevant, a two-day public meeting that included a number of presentations and during which public comments were received by the Panel, review of some of the materials provided during and after the meeting, and the Panel’s internal discussion and deliberations. The Board conducted a review of the current 2006 Bay-Delta Plan in 2009 and determined that Delta outflows and other requirements for the protection of fish and wildlife beneficial uses should be considered for revision. “Delta Outflows and Related Stressors” was further identified by the Delta Science Program as one of four topics emerging from a series of Board workshops in 2012 for which additional workshops should be conducted to provide input on the best available scientific information. Delta outflows and their management have been the subject of extensive scientific and management discussion for decades. A benchmark in this discourse is the report from a series of technical workshops facilitated by Dr. Jerry Schubel (Schubel et al. 1993). Schubel notes in the preface to that report that estuarine standards are required to protect the estuarine ecosystem from “further degradation” until “debate and disagreement over the relative importance of the benefits of low salinity habitat and therefore of flow, on the one hand, and of the liabilities of the physical diversion of a portion of that flow and the associated processes of entrainment of organisms, on the other,” can be resolved with a degree of scientific certainty acceptable to the Board. To some extent, this Panel has been asked to revisit whether standards for Delta outflow are still required, and to identify the degree of scientific certainty regarding the importance of Delta outflow to the ecosystem relative to other stressors.

Workshop on Improving Sub-Seasonal and Seasonal Precipitation Forecasting for Drought Preparedness

California Department of Water Resources (DWR) | October 15th, 2015

Skillful sub-seasonal (monthly) to seasonal (the water year) precipitation forecasting would support many facets of water management, providing lead time for preparing fo

Skillful sub-seasonal (monthly) to seasonal (the water year) precipitation forecasting would support many facets of water management, providing lead time for preparing for extreme events and allowing for more efficient operation of water infrastructure. Current forecast practices and scientific capabilities for making skillful forecasts beyond the weather time domain, however, are limited. Through a series of prior annual workshops on climate variability, climate extremes, and drought held by the Council and the California Department of Water Resources (CDWR), some possible opportunities for improving forecasting skill at a regional scale have been identified. The purpose of this May 2015 workshop was to develop a Western vision for improving monthly and seasonal precipitation forecasting, loosely modeled after the Council’s vision for an observing network for Western extreme precipitation. The analyses performed to understand patterns responsible for heavy precipitation events at a regional scale – such as atmospheric river storms or the Southwest monsoon -- also point out pathways to explore for improving forecasting of these events. The timing is ripe for efforts to improve monthly and seasonal forecasting. Drought in the West has called attention to the need for better information to support preparedness and response, and NOAA’s report on the California drought provides a focal point for followup actions. The National Weather Service (NWS) is reviewing approaches for developing experimental week three and week four outlooks. The National Research Council has convened a committee to develop a U.S. research agenda to advance subseasonal to seasonal forecasting.

Workshop on the Interior Delta Flows And Related Stressors Panel Summary Report

Delta Stewardship Council (Delta Council) | August 6th, 2014

On April 16 and 17, 2014, the Delta Science Program convened an expert Panel (the Panel) and a workshop to identify the best available science to inform the State Water R

On April 16 and 17, 2014, the Delta Science Program convened an expert Panel (the Panel) and a workshop to identify the best available science to inform the State Water Resources Control Board’s (the Board) decisions regarding interior Delta flow requirements to protect beneficial uses of water in the San Francisco Bay/Sacramento-San Joaquin Estuary (Bay-Delta Plan). This workshop and others were convened to provide advice to the Board on issues important to updating the 2006 Bay Delta Plan. At the workshop, the Panel (consisting of the authors of this report) heard presentations from a variety of experts on Delta flows and on species and ecological responses to flow. The Panel was also provided with a selection of scientific reports relevant to the effects of interior Delta flows on fish and their environment in the Delta. This report is informed by both the written and oral information provided to the Panel as well as by other publications that the Panel felt were necessary to satisfy its charge.  The Panel did not make a thorough independent search of the literature on the Sacramento-San Joaquin Delta to determine if there were additional publications that were relevant to its charge. In this report we summarize what is known about the direct and indirect relationships between interior Delta flows and listed fish species. We then use this knowledge to address a set of specific questions posed by the Delta Science Program and the Board.

Workshop report—Earthquakes and High Water as Levee Hazards in the Delta

Delta Stewardship Council (Delta Council) | September 30th, 2016

Earthquakes and high water as hazards to Delta levees were reviewed in a seven-hour workshop organized by the Delta Independent Science Board and held at the campus of th

Earthquakes and high water as hazards to Delta levees were reviewed in a seven-hour workshop organized by the Delta Independent Science Board and held at the campus of the University of California, Davis. Earthquake hazards in the Delta were described in terms of ground motions from Bay Area earthquakes, infrequent earthquake recurrence on faults beneath the Delta, and levee fills prone to earthquake-induced liquefaction. Large uncertainties attend all these seismic elements of levee hazard. Those uncertainties, according to presentations in the workshop, include whether the Delta ground motions previously computed for Bay Area earthquakes were too large.  Hazards from high water were deemed greatest from the confluence of high river discharge, wind-driven surge and waves, and high tides. Major risk assessments have used available data on these hazards without mandates to advance the science. Research needs and opportunities identified in the workshop include expanded observations of Delta ground motions, improved estimates of geologically recent displacement on faults beneath the Delta, further identification of liquefiable materials and mechanisms beneath levees, continued airborne measurements of land-level change, updated mapping of the contracting area of remaining peat, and fuller documentation of past levee failures. Recurring assessments of earthquake hazards and climate change provide precedents for periodic reappraisal of Delta levee risk. The workshop brought together different parts of the diverse community of Delta levee specialists. Positive responses to the workshop suggest that it served levee specialists and outsiders alike.

Workshop report—Earthquakes and High Water as Levee Hazards in the Sacramento-San Joaquin Delta

Delta Stewardship Council (Delta Council) | September 30th, 2016

World’s largest dam removal reverses coastal erosion

Nature Portfolio (Springer Nature) | September 27th, 2019

Wright et al v. Goleta Water District

Superior Court of California, County of Santa Barbara | November 17th, 1989

Wyandotte Creek Groundwater Subbasin Groundwater Sustainability Plan

Wyandotte Creek Groundwater Sustainability Agency | December 15th, 2021

The Wyandotte Creek Subbasin lies in the eastern central portion of the Sacramento Groundwater Basin. It is bounded on the west by the Feather River and Thermalito After

The Wyandotte Creek Subbasin lies in the eastern central portion of the Sacramento Groundwater Basin. It is bounded on the west by the Feather River and Thermalito Afterbay; in the south by the Butte-Yuba County line (except for Ramirez Water District which is fully within the North Yuba Subbasin); and on the north and east by the edge of the alluvial basin as defined by DWR Bulletin 118 - Update 2003 (DWR, 2003). It is surrounded by the Butte Subbasin to the west, the Wyandotte Creek Subbasin to the north, the North Yuba Subbasin to the south and the foothills to the east (Figure ES-2). The lateral boundaries of the Wyandotte Creek Subbasin are jurisdictional in nature, and it is recognized that groundwater flows across each of the defined boundaries to some degree.

Yolo Bypass Juvenile Salmon Utilization Study 2016— Summary of Acoustically Tagged Juvenile Salmon and Study Fish Releases, Sacramento River, California

U.S. Geological Survey (USGS) | September 12th, 2017

The Yolo Bypass is a flood control bypass in Sacramento Valley, California. Flood plain habitats may be used for juvenile salmon rearing, however, the potential value of

The Yolo Bypass is a flood control bypass in Sacramento Valley, California. Flood plain habitats may be used for juvenile salmon rearing, however, the potential value of such habitats can be difficult to evaluate because of the intermittent nature of inundation events. The Yolo Bypass Juvenile Salmon Utilization Study (YBUS) used acoustic telemetry to evaluate the movements and survival of juvenile salmon adjacent to and within the Yolo Bypass during the winter of 2016. This report presents numbers, size data, and release data (times, dates, and locations) for the 1,197 acoustically tagged juvenile salmon released for the YBUS from February 21 to March 18, 2016. Detailed descriptions of the surgical implantation of transmitters are also presented. These data are presented to support the collaborative, interagency analysis and reporting of the study findings.

Yolo Bypass Salmon Habitat Restoration and Fish Passage Analytical Tool Review

Delta Stewardship Council (Delta Council) | October 1st, 2017

NOAA’s National Marine Fisheries Service (NMFS) and the U.S. Fish and Wildlife Service (USFWS) have issued a Biological Opinion (BiOp) on the long-term operat

NOAA’s National Marine Fisheries Service (NMFS) and the U.S. Fish and Wildlife Service (USFWS) have issued a Biological Opinion (BiOp) on the long-term operations of the Central Valley Project (CVP) and State Water Project (SWP) that includes Reasonable and Prudent Alternatives (RPA) designed to alleviate jeopardy to listed species and adverse modification of critical habitat. NMFS’ RPA requires the U.S. Bureau of Reclamation (Reclamation) to increase juvenile flood plain rearing habitat and improve adult fish passage for ESA-listed salmonids and sturgeon. The BiOp requires seventy-three (73) habitat restoration actions, five of which are specific to the Yolo Bypass. The California Department of Water Resources (DWR) and Reclamation have developed project alternatives for the Draft Yolo Bypass Fish Passage and Habitat Restoration EIS/EIR focused on the following two Yolo Bypass actions, which are the subject of this review:  - Increase seasonal floodplain inundation in the lower Sacramento River Basin  - Improve fish passage throughout the Yolo Bypass Alternatives The alternatives developed to address these two actions consist of a notch in the Fremont Weir, with alternative locations and configurations (width and weir-crest elevations), designed to increase the frequency and duration of hydraulic connectivity between the main-stem Sacramento River and the Yolo Bypass and to improve fish passage. Six alternative locations / configurations for a notch were identified.