Scientist and Stakeholder Views on the Delta Ecosystem

Public Policy Institute of California (PPIC) | April 22nd, 2013

There is broad scientific recognition that a wide range of ecosystem stressors are responsible for the declines in native fish populations in the Sacramento–San Joaquin

There is broad scientific recognition that a wide range of ecosystem stressors are responsible for the declines in native fish populations in the Sacramento–San Joaquin Delta. But science and policymaking have been at odds about the roles of different stressors and the potential of various management actions to improve ecosystem health. In the summer of 2012, PPIC conducted two confidential surveys on the impact of ecosystem stressors: one sought input from scientific experts and the other focused on stakeholders and policymakers. This report analyzes the results and examines the implications of both surveys.

Scrutinizing the Delta Cross Channel

CALFED | June 1st, 2001

Sea level rise and the drivers of daily water levels in the Sacramento-San Joaquin Delta

Nature Portfolio (Springer Nature) | December 17th, 2023

Sediment Transport in Two Tributaries to the San Joaquin River Immediately Below Friant Dam—Cottonwood Creek and Little Dry Creek, California

U.S. Geological Survey (USGS) | May 2nd, 2023

Two tributaries to the greater San Joaquin River watershed, Cottonwood and Little Dry Creeks, in California’s Central Valley, were assessed for sediment and streamflow

Two tributaries to the greater San Joaquin River watershed, Cottonwood and Little Dry Creeks, in California’s Central Valley, were assessed for sediment and streamflow dynamics between October 1, 2011, and September 30, 2019. The two systems deliver sediment to the San Joaquin River below Friant Dam, California. Dams create downstream discontinuities in streamflow and sediment transport and therefore influence fish habitat and sediment dynamics. Because these two creeks are directly downriver from Friant Dam, they become the most upstream source of sediment to the San Joaquin River below Friant Dam. The quality and quantity of spawning habitat for fish in the gravel-bedded reach of the San Joaquin River relies on a range of bed material particle size suitable for redd structure. The effects of coarse-sand to fine-gravel supply on salmonid habitat depends primarily on the size of the sediment and the timing of its addition from tributaries to the San Joaquin River; thus, understanding the timing, quantity, and size of sediment supplied from these two tributaries is critical to the management of ecological and biological sustainability. Streamflow from Cottonwood and Little Dry Creeks, along with streamflow from the San Joaquin River below Friant Dam, were compared to continuously measured water-surface elevations to quantify the timing and direction of streamflow. Suspended-sediment samples were collected with multiple automatic samplers and analyzed for concentration and grain-size distribution. Measured suspended-sediment concentrations and streamflows were used to develop sediment rating curves and compute continuous estimates of suspended-sediment load for each tributary. Satellite imagery was used to qualify spatial and temporal dynamics through the lower watersheds and support more quantitative sediment-load estimates. Computed annual sediment loads ranged from 1.32x101 to 2.68x104 metric tons for Little Dry Creek and 9.82 to 1.98x103 metric tons for Cottonwood Creek. Sediment loads computed during the study period for both watersheds show that annual loads were highest during water year 2017 (October 1, 2016, to September 30, 2017). Sediment transport primarily occurred between the months of January and March. In both tributaries, grain-size distributions of suspended sediment were predominantly coarse-sized sand and were finer than the remnant bed material. Both creeks demonstrate backwater effects from the San Joaquin River, but the more tortuous stream channel and historical mining pits within Little Dry Creek provide more capacity for sediment storage compared to the less complex stream network of Cottonwood Creek. Because loads were computed based on upstream streamgages and not at the confluence of each tributary to the San Joaquin River, annual load estimates do not represent direct flux into the San Joaquin River; instead, these results indicated that in Little Dry Creek, particularly, the lowest portion of the watershed stores sediment before it reaches the San Joaquin River.

Selenium in White Sturgeon from North San Francisco Bay: The 2015-2017 Sturgeon Derby Study

San Francisco Estuary Institute (SFEI) | October 1st, 2019

This report presents the findings from a study evaluating selenium concentrations in white sturgeon (Acipenser transmontanus) tissues collected during the 2015-2017 Sturg

This report presents the findings from a study evaluating selenium concentrations in white sturgeon (Acipenser transmontanus) tissues collected during the 2015-2017 Sturgeon Derby events in North San Francisco Bay. The goal of this study was to investigate the distribution of selenium among sturgeon tissues to inform the toxicological and regulatory interpretation of selenium measured in non-lethally collected tissues, including muscle plugs and fin rays. This technical report provides documentation of the study and presents its major findings. 

Selenium in White Sturgeon Tissues: 2015 Sturgeon Derby

San Francisco Estuary Institute (SFEI) | August 1st, 2017

The Original Sturgeon Derby (Derby) is an annual fishing derby held in Bay Point, CA that presents an opportunity to collect and analyze a variety of tissue samples from

The Original Sturgeon Derby (Derby) is an annual fishing derby held in Bay Point, CA that presents an opportunity to collect and analyze a variety of tissue samples from angler-harvested white sturgeon (Acipenser transmontanus) for selenium (Se). Collection and analysis of these tissues from the 2015 Derby helped to: 1) develop non-lethal sampling methods and 2) better understand the correlation between tissues that can be collected non-lethally (muscle plug, fin ray) with those that are of greater toxicological interest (ovary, liver). Otolith samples were also collected to inform the development of methods for fin ray Se microchemical analysis. On January 31 and February 1, 2015, tissue samples were obtained from eight female and 19 male white sturgeon collected at the Derby and analyzed for Se. The fin rays were also used to estimate age of the fish, and the muscle plugs were analyzed for carbon (δ13 C), nitrogen (δ15 N), and sulfur (δ34 S) isotope ratios to provide information about recent habitat (e.g., primarily Delta, North Bay, or ocean) and foraging behavior (e.g., primarily clam- or fish-based diet). 

Shasta Dam Fish Passage Evaluation – Pilot Implementation Plan – U.S. Bureau of Reclamation

U.S. Bureau of Reclamation (USBR) | September 1st, 2015

Simplified 1-D Hydrodynamic and Salinity Transport Modeling of the Sacramento–San Joaquin Delta: Sea Level Rise and Water Diversion Effects

University of California, Davis (UC Davis) | December 11th, 2013

Skarry Removal

California State Lands Commission (SLC) | May 1st, 2025

The Commission’s contractor will remove booms, winches, and other superstructures from the crane barges on site. This equipment will be cut into pieces and placed on a

The Commission’s contractor will remove booms, winches, and other superstructures from the crane barges on site. This equipment will be cut into pieces and placed on a materials barge for recycling. Floating booms will surround the work site and contain any debris. Once lightened of equipment, a crane will remove the two smaller barges directly from the water. The largest barge will be refloated and towed by water to the Mare Island shipyard, where it will be removed from the water and demolished. Scrap metal will be recycled, and other debris will be hauled to a landfill for disposal. Click here for the staff report that accompanied the plan.

Small Tributaries Pollutants of Concern Reconnaissance Monitoring: Application of Storm-event Loads and Yields-Based and Congener-Based PCB Site Prioritization Methodologies

San Francisco Estuary Institute (SFEI) | January 12th, 2022

With RMP funding allocated in 2017 and 2018, a pilot study was completed using a subset of data from watersheds in San Mateo and Santa Clara Counties to build new methods

With RMP funding allocated in 2017 and 2018, a pilot study was completed using a subset of data from watersheds in San Mateo and Santa Clara Counties to build new methods for organizing and analyzing the existing stormwater reconnaissance data that will provide further evidence to support decisions about which watersheds may be of interest for prioritized management focus. The pilot study resulted in two new analysis methodologies outlined in two companion reports: Davis, J.A. and Gilbreath, A.N., 2019. Small Tributaries Pollutants of Concern Reconnaissance Monitoring: Pilot Evaluation of Source Areas Using PCB Congener Data. SFEI Contribution No. 956. San Francisco Estuary Institute, Richmond, California. McKee, L.J., Gilbreath, A.N., Hunt, J.A., Wu, J., Yee, D., and Davis, J.A., 2019. Small tributaries pollutants of concern reconnaissance monitoring: Loads and yields-based prioritization methodology pilot study. SFEI Contribution No. 817. San Francisco Estuary Institute, Richmond, California. In this final report, we describe a few enhancements to the storm-event loads and yields method and then apply both methods to a much larger data set and provide the resulting database to support stormwater management and decision making.