San Luis Obispo Coastkeeper v. Santa Maria Valley Water Conservation District

United States District Court, Central District of California | September 23rd, 2022

Scott Valley Integrated Hydrologic Model: Data Collection, Analysis, and Water Budget Final Report

University of California, Davis (UC Davis) | November 14th, 2017

The Scott Valley is an agricultural groundwater basin in Northern California, within the Scott River watershed and part of the much larger Klamath Basin watershed straddl

The Scott Valley is an agricultural groundwater basin in Northern California, within the Scott River watershed and part of the much larger Klamath Basin watershed straddling the California-Oregon border. The Scott River provides important habitat for salmonid fish, including spawning and rearing habitat for coho and fall-run Chinook salmon and steelhead trout. Sufficient flows at adequately low temperatures during summer, for rearing, and fall, for spawning, are critical for healthy fish habitat in the mainstem and tributaries. This report presents the data assembled and the methods used for data analysis and data modeling to prepare the Scott Valley Integrated Hydrologic Model Version 2, which is currently under development. The report includes precipitation data analysis, streamflow data analysis and modeling, geology and groundwater data review and analysis, evapotranspiration and soils data analysis, and preparation of relevant watershed, land use, topography, and irrigation data. The data collection and analysis efforts culminate in the development of a spatio-temporally distributed soil water budget model for the Scott Valley. The soil water budget model is used to determine spatially and temporally varying groundwater pumping rates, surface water diversion rates, and groundwater recharge across the groundwater basin. The spatial resolution of the soil water budget model is by individual fields (land use polygons). Temporal discretization is in daily time steps for the period from October 1, 1990 to September 30, 2011. This period includes several dry years, average years, and wet year periods. Methods and results of the soil water budget model are presented in this report. This report represents the next step toward a better understanding of the interactions between groundwater, surface water, land-use, and agricultural practices with a specific focus on the seasonal impacts of groundwater pumping on streamflow during critical low flow periods. The work presented here relies on an extensive data collection facilitated by the voluntary and active collaboration of communities, landowners, the Scott River Watershed Council (SRWC), the Siskiyou Resource Conservation District (SRCD), and the Scott Valley Groundwater Advisory Committee (GWAC) which has been appointed by the Board of Supervisors in January 2011, meeting monthly since April 2011 and advising UC Davis on its data collection and modeling efforts. In the data analysis and during the model development, numerous assumptions have been made as is common in building a conceptual and numerical integrated hydrologic model. Models cannot represent the complexity of the real system, but are an effort to capture salient hydrologic features with sufficient accuracy to develop modeling results that are useful for a better understanding of the watershed dynamics and water balance.

Sediment Mobility and River Corridor Assessment for a 140-Kilometer Segment of the Main-Stem Klamath River Below Iron Gate Dam, California

U.S. Geological Survey (USGS) | January 26th, 2021

This river corridor assessment documents sediment mobility and river response to flood disturbance along a 140-kilometer segment of the main-stem Klamath River below Iron

This river corridor assessment documents sediment mobility and river response to flood disturbance along a 140-kilometer segment of the main-stem Klamath River below Iron Gate Dam, California. Field and remote sensing methods were used to assess fundamental indicators of active sediment transport and river response to a combination of natural runoff events and reservoir releases during the study period from 2005 to 2019. Discharge measurements at two gaged sites and bed-material samples at two ungaged sites provided direct and indirect evidence of mobile bed conditions, scour and fill, and surface flushing of fine sediment. Available remote-sensing datasets collected in 2005, 2009, 2010, and 2016 were used to determine sediment storage, flood inundation boundaries, and provide indirect evidence of flood-induced scour. These datasets validate channel-maintenance flows defined by Shea and others (2016). During the study period, flows greater than or equal to 6,030 cubic feet per second mobilized the substrate, caused localized scour, and flushed fine sediment from bar surfaces. Flows greater than or equal to 10,400 cubic feet per second stripped vegetation from bars and floodplains and produced deeper scour. Flood disturbance within the study reach is produced by the combined effect of natural flows and reservoir releases, which resulted in mobile bed conditions during the study period. Periodic scour and substrate disturbance are considered by the U.S. Fish and Wildlife Service to be integral for managing disease-induced mortality of juvenile and adult salmonids. Substrate conditions conducive to parasites that host infectious diseases, particularly Ceratonova shasta, occur periodically. Additional studies are required to determine whether disease prevalence can be mitigated by well-timed reservoir releases. Study results are useful for interpreting linkages among physical and biological processes and for evaluating the effectiveness of flow management targeted to improve river bed conditions for endangered salmonid populations.

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 Muscle Plugs of White Sturgeon from North San Francisco Bay, 2015-2017

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

This report presents the findings from a study evaluating selenium concentrations in white sturgeon (Acipenser transmontanus) muscle tissues collected from live sturgeon

This report presents the findings from a study evaluating selenium concentrations in white sturgeon (Acipenser transmontanus) muscle tissues collected from live sturgeon during the California Department of Fish and Wildlife’s fall sturgeon tagging studies in North San Francisco Bay. The goal of this study was to non-lethally collect a large number of sturgeon muscle plugs and analyze them for selenium to (1) establish an understanding of current status, trends, and causes of variability in sturgeon muscle selenium concentrations; and (2) evaluate the potential for long-term sturgeon selenium monitoring with muscle plugs, through development of field and laboratory methods and informing the monitoring design. Monitoring of selenium in white sturgeon is needed to evaluate the effectiveness of the North Bay Selenium Total Maximum Daily Load (TMDL) in protecting sturgeon from selenium toxicity. This technical report provides documentation of the study and presents its major findings in the context of all historically available data on sturgeon muscle selenium concentrations in San Francisco Bay. 

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

Significant challenges to the sustainability of the California coast considering climate change

National Academy of Sciences (NAS) | July 29th, 2024

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