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  • Title

    Monitoring and Evaluation of the North Delta Food Subsidies and Colusa Basin Drain Study

    Lead California Department of Water Resource [DWR]
    Description The North Delta Food Subsidies – Colusa Basin Drain Study monitors and evaluates the effects of the North Delta Flow Action on the Delta food web.
    Science topics Delta Smelt, Fish, Flows, Water management
    Updated November 17, 2022
  • Title

    Directed Outflow Project

    Lead U.S. Bureau of Reclamation [USBR]
    Description The U.S. Bureau of Reclamation (USBR) and California Department of Water Resources (DWR), along with collaborators, are continuing efforts to evaluate the hypothesized benefits of outflow and outflow alteration for Delta Smelt. The collective aim of these efforts is to better inform management actions that will bolster and stabilize the Delta Smelt population. The planned five-year Directed Outflow Project (DOP) seeks to assist in evaluating the overarching hypothesis that habitat quality and quantity is improved in the summer/fall when X2 is below 81 km and the LSZ occurs in Suisun Bay and Marsh, and this improvement in habitat conditions will translate into a greater catch density, health, and growth for Delta Smelt using this area
    Science topics Delta Smelt, Fish, Flows, Water management
    Updated November 17, 2022
  • Title

    Monitoring and Assessment of Suisun Marsh Salinity Control Gates Action

    Lead California Department of Water Resource [DWR]
    Description The Suisun Marsh Salinity Control Gates (SMSCGs) have the potential to provide an increase in low-salinity-zone habitat for endangered Delta Smelt. Operation of the SMSCGs in summer and fall to improve Delta Smelt habitat are called for in the Biological Opinion and Incidental Take permit for the Central Valley Project and State Water Project. To support the adaptive management of the action, DWR is planning to monitor the change in water quality, phytoplankton, zooplankton, fishes, and clams resulting from the action.
    Science topics Delta Smelt, Phytoplankton, Salinity
    Updated November 17, 2022
  • Title

    Suisun Marsh Salinity Control Gates Action Pilot Study

    Lead California Department of Water Resource [DWR]
    Description In summer 2018 we used a unique water control structure in the San Francisco Estuary to direct a managed flow pulse into Suisun Marsh. Field monitoring showed that turbidity and chlorophyll were at higher levels in Suisun Marsh, representing better habitat conditions, than the upstream Sacramento River region throughout the study period. Fish monitoring data suggested that small numbers of Delta Smelt colonized Suisun Marsh from the Sacramento River during the 2018 Flow Action.
    Science topics Delta Smelt, Phytoplankton, Salinity
    Updated September 28, 2023
  • Title

    Delta Landscape Scenario Planning Tool

    Lead San Francisco Estuary Institute [SFEI]
    Description The Delta Landscapes Scenario Planning Tool is a set of resources to assist users with developing, analyzing, and evaluating different land use scenarios in the Delta. The tool is designed to inform ongoing and future restoration planning efforts by assessing how proposed projects will affect a suite of landscape metrics relating to desired ecosystem functions.
    Science topics Fish, Landscape metrics, Marsh wildlife, Restoration planning, Riparian wildlife, Sea level rise, Terrestrial wildlife
    Updated November 17, 2022
  • Title

    Delta Regional Monitoring Program Mercury Monitoring

    Lead Delta Regional Monitoring Program [RMP]
    Description Monitoring of sport fish and water was conducted by the Delta Regional Monitoring Program (Delta RMP) from August 2016 to April 2017 to begin to address the highest priority information needs related to implementation of the Sacramento–San Joaquin Delta Estuary Total Maximum Daily Load (TMDL) for Methylmercury (Wood et al. 2010). Two species of sport fish, largemouth bass (Micropterus salmoides) and spotted bass (Micropterus punctulatus), were collected at six sampling locations in August and September 2016. The length-adjusted (350 mm) mean methylmercury (measured as total mercury, which is a routinely used proxy for methylmercury in predator fish) concentration in bass ranged from 0.15 mg/kg or parts per million (ppm) wet weight at Little Potato Slough to 0.61 ppm at the Sacramento River at Freeport. Water samples were collected on four occasions from August 2016 through April 2017. Concentrations of methylmercury in unfiltered water ranged from 0.021 to 0.22 ng/L or parts per trillion. Concentrations of total mercury in unfiltered water ranged from 0.91 to 13 ng/L. Over 99% of the lab results for this project met the requirements of the Delta RMP Quality Assurance Program Plan, and all data were reportable. This data report presents the methods and results for the first year of monitoring. Historic data from the same or nearby monitoring stations from 1998 to 2011 are also presented to provide context. Monitoring results for both sport fish and water were generally comparable to historic observations. For the next several years, annual monitoring of sport fish will be conducted to firmly establish baseline concentrations and interannual variation in support of monitoring of long-term trends as an essential performance measure for the TMDL. Monitoring of water will solidify the linkage analysis (the quantitative relationship between methylmercury in water and methylmercury in sport fish) in the TMDL. Water monitoring will also provide data that will be useful in verifying patterns and trends predicted by numerical models of mercury transport and cycling being developed for the Delta and Yolo Bypass by the California Department of Water Resources (DWR).
    Science topics Biosentinels, Fish, Methylmercury, Restoration, Water
    Updated November 17, 2022
  • Title

    Operation Baseline Project 2B: Phytoplankton, CSU Maritime Academy

    Lead California State University Maritime Academy
    Description Planned upgrades to the Sacramento Regional wastewater treatment plant (Regional San) between 2019 and 2021 will reduce total nitrogen inputs by >60% and shift the dominant form of nitrogen entering the Delta from ammonium (NH4) to nitrate (NO3). These changes will affect the Delta in ways unforeseeable with existing knowledge. The focus of this project is to quantify the links between wastewater nitrogen and phytoplankton standing stock, community composition and carbon and nitrogen production. Working in collaboration with the other two Operation Baseline projects, we will: 1. validate in situ monitoring approaches for phytoplankton standing stock and community composition (i.e. using size-fractionated chlorophyll-a and diagnostic phytopigments via HPLC) and 2. provide estimates of ambient and nitrogen-saturated phytoplankton NH4 and NO3 uptake rates as well as C uptake. Phytoplankton N and C uptake rates will be made along spatial gradients in nitrogen and water residence time (Task 1) and in three wetland habitats with varying influence from wastewater nitrogen (Task 3). Together with the other proposals, this project will provide much needed baseline characterization of nutrient processes in the Delta prior to Regional San upgrades.
    Science topics Algae, Floating aquatic vegetation, Food webs, Nitrogen / ammonia, Open water, Other discharge contaminants, Phytoplankton, Submerged aquatic vegetation, Wastewater discharge, Water operations / exports, Wetlands, Zooplankton
    Updated December 14, 2022
  • Title

    Operation Baseline Project 2C: Zooplankton, Romberg Tiburon Center, SFSU

    Lead San Francisco State University [SFSU]
    Description This project will examine responses of zooplankton (copepods) to variations in the foodweb attributable to nutrient sources. At each wetland site we will determine spatial abundance patterns and rates of reproduction, growth, and mortality. These will be integrated with information on phytoplankton and physical dynamics to determine how population dynamics responds to nutrient conditions. Stable isotopes will be used to assess nutrient source contributions to growth.
    Science topics Algae, Floating aquatic vegetation, Food webs, Nitrogen / ammonia, Open water, Other discharge contaminants, Phytoplankton, Submerged aquatic vegetation, Wastewater discharge, Water operations / exports, Wetlands, Zooplankton
    Updated December 14, 2022
  • Title

    Effects of copper exposure on the olfactory response of Delta smelt [Hypomesus transpacificus]: Investigating linkages between morphological and behavioral anti-predator response

    Lead University of California - Davis [UC Davis]
    Description This study aimed to address the question of how water-borne copper can affect the ability of delta smelt to detect predator related odorants and conduct essential behaviors. To do this, the project included a thorough morphological and cytological study of the delta smelt olfactory organ, which had previously not been well-studied. The researchers also characterized the olfactory mediated antipredatory response to alarm cues and assessed the effects of copper exposure on the anti-predator behavior and morphology of the olfactory rosette of delta smelt.
    Science topics Copper, Delta Smelt, Toxicity
    Updated November 17, 2022
  • Title

    Effect of temperature and salinity on physiological performance and growth of longfin smelt: Developing a captive culture for a threatened species in the Sacramento- San Joaquin Delta

    Lead University of California - Berkeley [UC Berkeley]
    Description This research project aimed to improve understanding of the physiological requirements for survival and reproduction across the entire life history of longfin smelt (from egg to larvae to juvenile to reproducing adult). The overall goals of this project were to assist in developing a captive longfin smelt culture and assess longfin smelt responses to multiple stressors across all life stages, which has been difficult because of extremely low (<10%) larval survival of these fish.
    Science topics Delta Smelt, Longfin Smelt, Salinity, Temperature
    Updated November 17, 2022
  • Title

    Yolo Bypass Salmonid Habitat Restoration and Fish Passage

    Lead California Department of Water Resource [DWR]
    Description The Yolo Bypass Salmonid Habitat Restoration Project works to reconnect the floodplain for fish during the winter season and improve connectivity within the bypass and to the Sacramento River. The project provides seasonal inundation that mimics the natural process of the Yolo Bypass floodplain and improves connectivity within the bypass and to the Sacramento River.
    Science topics Chinook Salmon, Endangered species
    Updated April 29, 2022
  • Title

    Yolo Bypass Salmonid Habitat Restoration and Fish Passage: Scenario Analysis of Fremont Weir Notch – Integration of Engineering Designs, Telemetry, and Flow Fields

    Lead U.S. Army Corps of Engineers [USACE]
    Description This study analyzes 12 notch scenarios in the Fremont Weir in terms of entrainment of juvenile salmon. The goal is to quantify the relative entrainment rates (between 0 and 1) across the suite of scenarios and to identify possible strategies for enhancing entrainment outcomes. This study does not predict future entrainment as models generally do not predict future outcomes so much as highlight trends
    Science topics Chinook Salmon, Endangered species, Water conveyance / infrastructure
    Updated April 29, 2022
  • Title

    Reevaluating ecosystem functioning and carbon storage potential of a coastal wetland through integration of lateral and vertical carbon flux estimates

    Lead University of Washington [UW]
    Description This study aims to produce an integrated, net ecosystem carbon budget for Suisun Marsh, a representative ecosystem in the delta. This project combines diverse measurements on land and in the adjacent marine environment to produce the first directly measured, complete carbon budget for a coastal wetland habitat. This work has generated a more complete picture of the potential of wetland preservation for greenhouse gas reduction, as well as the processes that shape wetland accretion and resilience to sea-level rise. The project will provide vital information for understanding the ecosystem services, food webs, and carbon storage potential of the region’s wetlands, as well as provide new methodology that could be used by researchers around the world.
    Science topics Atmosphere, Carbon, Carbon storage, Evaporation / evapotranspiration, Non-forested vegetation, Sea level rise, Sediments, Surface water / flow, Wetlands
    Updated November 17, 2022
  • Title

    Do light, nutrient, and salinity interactions drive the “bad Suisun” phenomenon? A physiological assessment of biological hotspots in the San Francisco Bay-Delta

    Lead University of California - Santa Cruz [UCSC]
    Description This project assessed the physiological basis for reduced phytoplankton growth in Suisun Bay, prior to the major upgrade at the Sacramento Regional Wastewater Treatment Plant (SRWTP), which is responsible for 90% of the nitrogen released into the bay. The work involved analyzing almost three decades of historical eld data from the bay-delta and using it to build a model to evaluate environmental drivers of phytoplankton biomass. Discoveries from the eld data were then tested through laboratory culturing experiments. By illuminating the interacting e ects of bottom- up drivers (light, nutrients, salinity) on phytoplankton, this research helps provide a fundamental understanding of this complex ecosystem.
    Science topics Ammonia, Flushing rates, Light, Open water, Pelagic fish, Phytoplankton, Salinity, Wastewater discharge, Water temperature
    Updated November 17, 2022
  • Title

    Simulating methylmercury production and transport at the sediment-water interface to improve the water quality in the Delta

    Lead University of California - Merced [UC Merced]
    Description The aim of this project was to improve basic knowledge of mercury cycling and aid management of net methylmercury production in the delta by developing a kinetic-thermodynamic reaction model that describes and quantifies mercury cycling in delta sediments. The model was used to assess uncertainties and estimate methylation and demethylation rates — the processes by which methylmercury is produced and breaks down. In addition, the project examined coupling of mercury cycling with cycling of iron, sulfur, and manganese.
    Science topics Bioaccumulation, Chemistry, Hg and methyl mercury
    Updated November 17, 2022
  • Title

    Operation Baseline Project 1: Conceptual Framework

    Lead Delta Stewardship Council
    Description A multidisciplinary team will develop a thorough conceptual model that will describe current conditions and consider changes from the WWTP upgrade. The model will be used to identify the highest priority science questions and investigations to pursue before, during, and after the plant upgrade.
    Science topics Algae, Floating aquatic vegetation, Food webs, Nitrogen / ammonia, Open water, Other discharge contaminants, Phytoplankton, Submerged aquatic vegetation, Wastewater discharge, Water operations / exports, Wetlands, Zooplankton
    Updated December 14, 2022
  • Title

    Operation Baseline Project 2A1: USGS Pilot Studies

    Lead U.S. Geological Survey [USGS]
    Description Two pilot studies were funded to establish a baseline in open water and shallow wetland habitats prior to the WWTP upgrade. Study 1: Nutrient concentrations, transformation rates, and links to the foodweb. Study 2: Method to improve monitoring using fixed stations coupled with high-speed boat measurements
    Science topics Algae, Floating aquatic vegetation, Food webs, Nitrogen / ammonia, Open water, Other discharge contaminants, Phytoplankton, Submerged aquatic vegetation, Wastewater discharge, Water operations / exports, Wetlands, Zooplankton
    Updated December 14, 2022
  • Title

    Operation Baseline Project 2A2: USGS Pilot Studies - Isotopes

    Lead U.S. Geological Survey [USGS]
    Description Evaluate the usefulness of stable isotopes to trace nutrients form effluent water
    Science topics Algae, Floating aquatic vegetation, Food webs, Nitrogen / ammonia, Open water, Other discharge contaminants, Phytoplankton, Submerged aquatic vegetation, Wastewater discharge, Water operations / exports, Wetlands, Zooplankton
    Updated December 14, 2022
  • Title

    The Effect of Drought on Delta Smelt Vital Rates

    Lead University of California - Davis [UC Davis]
    Description This Project is necessary to obtain a better understanding of the effects of drought and management's response to drought on the Delta Smelt in order to avoid extinction. This study will test predication from other models to evaluate the impact of drought and management measures on Delta Smelt responses in terms of growth, phenotype diversity and survival during the spring and summer, when drought impacts are greatest.
    Science topics Delta Smelt, Drought
    Updated November 18, 2022
  • Title

    Defining the fundamental niche of Longfin Smelt [Spirinchus thaleichthys]: Physiological mechanisms of environmental tolerance.

    Lead University of California - Davis [UC Davis]
    Description This Project will evaluate reproductive output, embryo to larval development, and growth and maturation of Longfin Smelt (Spirinchus thaleichthys). This Project is designed to comprehensively assess effects of extreme events and their interaction with contaminant effects, and aims to fill knowledge gaps relating to turbidity (e.g., stress levels associated with predation risk), age-specific fecundity, egg and early larval buoyancy, and other essential requirements for captive rearing conditions that will aid the successful culture.
    Science topics None specified
    Updated April 29, 2022
  • Title

    Impact of Spatial and Temporal Dynamics of Water Flows on Migratory Behavior of Chinook Salmon Smolts in the South Delta

    Lead University of California - Davis [UC Davis]
    Description Funding for this study project will be use track the swimming movements of salmon smolts during migration using acoustic transmitters and detection arrays near the confluence of Old River and the San Joaquin River. Analyses will be carried out to determine swimming velocity relative to current velocity. Modeling will estimate fish distribution; fish transit times; entrainment of fish into channels of the south Delta; and alternative water export management scenarios that may result in reduced entrainment.
    Science topics None specified
    Updated November 19, 2022
  • Title

    Identifying the Causes of Feminization of Chinook Salmon in the Sacramento and San Joaquin River System

    Lead University of California - Berkeley [UC Berkeley]
    Description Purpose was to assess the potential importance of endocrine-disrupting chemical contaminants to salmon and other resident speices of waters that are discharged into the San Francisco-San Joaquin Delta.
    Science topics Chinook Salmon
    Updated April 29, 2022
  • Title

    How Abiotic Processes, Biotic Processes, and Their Interactions Sustain Habiata Charactersitics and Functions in River Channels and Their Floodplains: An Investigation of How a Reach of the Merced River Responds to Restoration

    Lead University of California - Santa Barbara [UCSB]
    Description The purpose of this project is to determine how river restoration affects the abundance and distribution of salmonid and non-salmonid fishes at critical life stages. The proposal involves field survey of hydraulics, sedimentation processes, channel changes, habitat conditions, invertebrate and fish communities and their interactions.
    Science topics None specified
    Updated April 29, 2022
  • Title

    Predicting the Effects of Invasive Hydrozoa [Jellyfish] on Pelagic Organisms Under Changing Salinity and Temperature Regimes

    Lead University of California - Davis [UC Davis]
    Description The purpose of this project seeks to investigate the potential effects of jellyfish, a devising invader of some ecosystems, on the SFE ecosystem, to determine the key factors allowing successful establishment and spread of these species, and to predict future effects and spread of the invasions.
    Science topics Water temperature, Salinity, Pelagic fish, Jellyfish
    Updated April 29, 2022
  • Title

    Climate change impacts to San Francisco Bay-Delta wetlands: Links to pelagic food webs and predictive responses based on landscape modeling

    Lead San Francisco State University [SFSU]
    Description The purpose of this project is to 1) evaluate the potential impacts of climate change on SF Bay-Delta tidal wetlands, 2) improve our understanding of the linkage between these wetlands and the pelagic food web, especially fish populations, and 3) use this information to make predictions about potential effects of climate change on Bay-Delta fish populations.
    Science topics Pelagic fish, Wetlands
    Updated April 29, 2022
  • Title

    Comparison of Nutrient Sources and Phytoplankton Growth and Species Composition in Two Rivers: Their Roles in Determining Productivity and Food Web Conditions in Suisun Bay and the Delta

    Lead San Francisco State University [SFSU]
    Description
    Science topics Phytoplankton, Pelagic fish, Nitrogen / ammonia
    Updated April 29, 2022
  • Title

    The Transport and Dispersion of Rafting Vegetation in the Sacramento-San Joaquin Delta

    Lead University of California - Berkeley [UC Berkeley]
    Description The research we are proposing here is focused on developing a thorough, mechanistic understanding of how rafting vegetation, such as hyacinths or egeria, is transported in the Sacramento-San Joaquin Delta. Our approach is to examine in detail the forces that act on rafts of vegetation, and the resulting raft accelerations, to establish a predictive model of raft pathlines. Our model development will be built around a series of field experiments that include measurements of raft movement using GPS-logging drifters integrated into rafts, tidal and wind-forcing using a boat mounted current profiler and an anemometer, and direct estimation of the water-induced shear stress using a point velocity meter incorporated into the actual rafts. These field observations will be used to critically evaluate a numerical model of both channel (tidal) flows and resulting raft movement. Our initial development will include a highly-resolved channel flow model, which will explicitly capture more lateral variability, including low velocity side “pockets”, than is typically resolved with Delta scale hydrodynamic models. Initially, this will allow us to carefully evaluate the quality of our raft tracking calculations. Once the approach is established to be accurate, however, these high-resolution flows will be used to numerically calculate the effective advection and dispersion of rafts in the Delta channel under consideration. This analysis will be focused on parameterizing the effects on raft transport of structures and processes that are unresolved in typical Delta hydrodynamics models. An example of a process that is likely to be important to parameterize is the trapping and retention of rafts along the perimeter of channels due to off-axis wind forcing, and the resulting along-channel dispersion of rafts. In order to examine the effective advection and dispersion of rafts in Delta channels, we propose to pursue this combination of field and numerical studies of raft transport in locations of increasing complexity: first in idealized, straight channels, then in a natural, sinuous channel and a channel junction, and finally throughout the entire Delta. Our research is strongly motivated by the desire to provide a predictive model of dispersion in the Delta for floating objects that respond to both wind and tidal forcing. Immediate applications involve the movement of hyacinth rafts and egeria to evaluate potential management strategies. Important future applications are likely to include consideration of other biological invasions, due to the potential for rafts to provide a transport pathway, and analysis of the movement of accidental or intentional releases of floating material in the Delta.
    Science topics None specified
    Updated November 29, 2022
  • Title

    The Consequences of Operational Decisions on Water Quality: Reconciling Delta Smelt, Salmon, and Human Needs

    Lead Contra Costa Water District [CCWD]
    Description The purpose of this project is to assess the consequences of actions taken to protect threatened or endangered Chinook salmon species relative to other upstream and in-Delta water management actions that have changed seasonal salinity in the Delta, thus reducing the ability of delta smelt to survive as a species;and, to investigate with modeling scenarios the potential to ameliorate this trade-off with specific operational actions.
    Science topics Delta Smelt, Chinook Salmon
    Updated April 29, 2022
  • Title

    A Calibration-Free Approach to Modeling Delta Flows and Transport

    Lead University of California - Berkeley [UC Berkeley]
    Description The purpose of this project is to develop and evaluate an integrated system for the prediction of Delta flows and transport in real-time that doesn't rely upon historical data sets for calibration and validation. The system consists of observational and computational components, along with real-time communication and coordination.
    Science topics None specified
    Updated April 29, 2022
  • Title

    Pilot Mark-Recapture Study to Estimate Delta Smelt Pre-Screen Loss and Salvage Efficiency

    Lead U.S. Fish and Wildlife Service [USFWS]
    Description The purpose of this project is to perform a study to determine whether it is feasible to quantify entrainment losses of juvenile and adult delta smelt due to water exports. This information is critical to better understanding the movement of Delta smelt in the system.
    Science topics Delta Smelt
    Updated April 29, 2022
  • Title

    Are Apparent Sex Reversed Chinook Salmon a Symptom of Genotoxicity?

    Lead University of California - Davis [UC Davis]
    Description Goal was to test the relative importance of chemical stressors on population viability and genetic diversity for fall-run Chinook salmon (in association with environmental contaminant exposure in the Central Valley delta).
    Science topics Chinook Salmon
    Updated April 29, 2022
  • Title

    Using Flowcam Technology to Measure High Frequency Spatial and Temporal Variation in Phytoplankton and Zooplankton Species Composition and Develop State-of-the-Art Plankton Monitoring

    Lead California Department of Water Resource [DWR]
    Description The purpose of this project is to use the new imaging-in-flow instrument FlowCAM to rapidly and automatically identify, enumerate and estimate biomass for in situ and laboratory phytoplankton and zooplankton species composition samples in the SF Estuary.
    Science topics Phytoplankton, Zooplankton
    Updated April 29, 2022
  • Title

    A Non-Point Source of Contaminants to the Estuarine Food Web: Mobilized Particles from the Intertidal Zone

    Lead California State University [CSU]
    Description The purpose of this research project is to quantify the process of contaminant concentration and resuspension of shallow and intertidal cohesive sediments at sites along the salinity gradient from Prospect Island to San Pablo Bay. This research is important because it helps to understand the pathways by which contaminants are assimilated, which is essential to appropriately manage habitat areas.
    Science topics None specified
    Updated April 29, 2022
  • Title

    A Statistical Model of Central Valley Chinook Incorporating Uncertainty

    Lead R2 Resource Consultants Inc.
    Description The purpose of this project is to develop a statistical modeling approach to the two Central Valley Chinook Salmon species that incorporates mortality in all phases of salmon life history, and includes the effects of uncertainty in assessing population status, guiding future research, and making management decisions.
    Science topics Chinook Salmon
    Updated April 29, 2022
  • Title

    Quantifying Factors Affecting Migration Routing and Survival of Juvenile Late-Fall Chinook Salmon in the Sacramento-San Joaquin River Delta

    Lead U.S. Geological Survey [USGS]
    Description Juvenile Chinook salmon emigrating from natal tributaries of the Sacramento River must negotiate the Sacramento-San Joaquin River Delta where they disperse among the Delta's complex channel network. Natural processes and water management actions affect the fraction of the population using different migration routes through the Delta and survival within those routes, but quantifying these relationships has proven difficult. Since 2006, acoustic telemetry techniques have been used to quantify both movement among migration routes and survival within routes, providing the first insights into how route-specific survival contributes to population-level survival in the Delta. In this project, we propose to use existing acoustic telemetry data from multiple sources to 1) Quantify factors affecting migration routing of juvenile salmon emigrating from the Sacramento River, 2) Quantify factors affecting survival of juvenile salmon within specific migration routes, and 3) Simulate population-level survival through the Delta under a limited number of historical and operational scenarios. Collating telemetry data from multiple sources over numerous years offers a unique opportunity to identify important relationships that might otherwise be difficult to detect for any particular study in a given year. Quantifying such relationships is critical to informing resource management that seeks to balance use of water resources with recovery of endangered salmon populations.
    Science topics Chinook Salmon
    Updated April 29, 2022
  • Title

    Habitat Values of Native SAV [Submerged Aquatic Vegetation] in the Low Salinity Zone of San Francisco Estuary

    Lead San Francisco State University [SFSU]
    Description We will investigate the importance of native submerged aquatic vegetation (SAV) in providing food web support for native fish species in the low salinity zone of the San Francisco Bay-Delta. These SAV beds, composed primarily of Stuckenia pectinata (sago pondweed), are an extensive feature along many of the islands in Suisun Bay and the west Delta, yet almost nothing is known of their seasonal or interannual patterns, their invertebrate communities, or how their physical structure or food resources influence use by native fishes. We hypothesize that the position of these beds in the shallow subtidal zone along the islands increases habitat options adjacent to wetlands and channels for numerous fish species, including species of concern such as delta smelt and chinook salmon. The objectives of this project are to: 1) characterize patterns in habitat structure, community composition, and productivity of SAV beds in four locations in Suisun Bay and the western Delta over a three year period (with comparisons to non-native Egeria densa beds), 2) document the epifaunal invertebrate community composition and abundance in the Stuckenia beds, 3) assess fish use of these beds through seining and acoustic monitoring of hatchery-tagged fish, 4) utilize stable isotope analyses to evaluate food web relationships within and among the beds, and 5) begin preliminary evaluation of the potential to restore native SAV to subsided lands in this region.
    Science topics Chinook Salmon, Green sturgeon, White Sturgeon, Sacramento Splittail, Delta Smelt, Steelhead Trout
    Updated April 29, 2022
  • Title

    Physiological Mechanisms of Environmental tolerance in Delta Smelt [Hypomesus transpacificus]: From Molecules to Adverse Outcomes

    Lead University of California - Davis [UC Davis]
    Description The proposed project directly addresses priority research detailed by the Delta Science Program to protect native fishes that depend on the Bay-Delta system focusing on adaptations to local habitats and physiological tolerances to key environmental stressors;in delta smelt (Hypomesus transpacificus). Temperature and salinity changes associated with anthropogenic climate change are likely to further exacerbate delta smelt population declines. We hypothesize that delta smelt tolerance to forecasted temperature rises and salinity intrusions into the Bay-Delta system can be assessed at a mechanistic level, and that acclimation thresholds can be established by means of genomic responses. This proposal builds upon successful development of a cDNA microarray for delta smelt containing approximately 2000 individual gene fragments, and the subsequent application of biomarkers for assessing the effects of chemical stressors on larval development with links to swimming behavior. We propose to develop a Next Generation oligonucleotide microarray in delta smelt, with ca. 15K genes, in order to assess mechanistic tolerance to changes in gemperature and salinity. Genomic studies will be conducted integrating effects on energetic activity and swimming performance studies, in an interdisciplinary approach that will permit the establishment of links between tolerance mechanisms and adverse outcomes.
    Science topics Delta Smelt, Water temperature, Salinity, Turbidity
    Updated April 29, 2022
  • Title

    Nutritional Quality of Zooplankton as Prey for Fish in the Sacramento-San Joaquin Dalta

    Lead University of California - Davis [UC Davis]
    Description Primary consumers (zooplankton) are a critical trophic link for energy transfer to upper trophic levels and a key food source for threatened and endangered fish species in the Delta. The zooplankton community was shaped by large spatial and temporal changes in both abundances and species composition that affected quantity of zooplankton carbon. It is also expected that taxonomic shifts affected quality of zooplankton carbon for fish due to altering biomass transfer at the base of the food web that can profoundly influence nutritional quality and population dynamics at higher trophic levels. Yet the biochemical composition of plankton remains largely unstudied in this system despite the fact that the importance of zooplankton nutritional quality for fish is one potential major component for the long-term decline and more recent collapse of pelagic fish species. The proposed research aims to measure essential nutritional status (stoichiometry, fatty acids, sterols) for zooplankton taxa and will calculate food-quality indices for fish. On the basis of nutritional plankton and biomass values, spatial patterns as well as long-term and recent changes in plankton quality associated with compositional shifts will be estimated. We propose that through integrating plankton food-quality into the management and restoration plan for the Delta, the dynamics of the ecosystem can be viewed from a new perspective that has key implications for understanding the decline in pelagic organisms.
    Science topics Zooplankton
    Updated April 29, 2022
  • Title

    An Open-Source, Three-Dimensional Unstructured-Grid Model of the Sacramento/San Joaquin Delta: Model Construction and Application to Delta Hydrodynamics and Temperature Variability

    Lead Stanford University
    Description Motivated by the need to predict transport in the Delta, this project will apply the open-source, unstructured-grid computer model, SUNTANS (Stanford Unstructured Nonhydrostatic Terrain following Adaptive Navier Stokes simulator) to the Sacramento/San Joaquin Delta. SUNTANS solves the governing equations of fluid flow on a grid that permits fine detail in areas of particular interest in the Delta, while allowing us to include the entirety of the Bay/Delta system so as to properly model oceanic and estuarine influences on the Delta We have two aims:(1) to carry out the model development needed to apply SUNTANS to the Delta;(2) to apply the model to look at aspects of the physical variability of the Delta that are critical to ecosystem function and to understanding how physical processes in the Delta affect ecosystem function, most notably entrainment of fish and other organisms by the export facilities. In particular, we propose to look at flow behavior at channel junctions, a key aspect of Delta hydrodynamics that influences dispersion in the Delta and thus the transport of biota, nutrients and contaminants. We also will examine the dynamics of spatial and temperature variability in the Delta in response to tides, atmospheric forcing, river flows, and diversions, variability that must be properly calculated to forecast how climate change and altered project operations may affect key species like Delta Smelt. We will carry out new fieldwork to support our modeling.
    Science topics Water temperature
    Updated April 29, 2022
  • Title

    Integrating Ecosystems, Flood Control, Agriculture, and Water Supply Benefits: An Application to the Yolo Bypass

    Lead University of California - Davis [UC Davis]
    Description The Yolo Bypass presents an opportunity to develop mechanisms governing the management of flows across floodplains that balance ecosystem services with economic and recreational functions, and to study the untapped potential of such floodplains to play a role in conjunctive surface and groundwater management. Analysis to the necessary high degree of spatial resolution for such management decisions is generally lacking for the Yolo Bypass. This proposal seeks funding for an interdisciplinary study to better understand the economic, hydrologic, and ecological functioning of land and water across the bypass, and to develop tools that use this knowledge in identifying promising strategies for the timing and configuration of spring inundation. Agronomic, economic, and hydraulic models will be used with formal interviews to study the relationship between flooding and six Yolo Bypass functions: (1) Agricultural Economics, (2) Waterfowl management, (3) Native Fish habitat, (4) Flood Control, (5) Groundwater storage, and (6) Recreation. Data from these first efforts will be incorporated into an optimization model that identifies promising inundation alternatives for ecosystem services which minimize costs to landowners and waterfowl managers, and maximize potential conjunctive use benefits. This synthesis answers the Delta Science Program's request for coupled hydrologic and ecosystem models, and for water and ecosystem management decision support system development.
    Science topics None specified
    Updated April 29, 2022
  • Title

    CASCaDE II: Computational Asessments of Scenarios of Change for the Delta Ecosystem

    Lead U.S. Geological Survey [USGS]
    Description This proposal builds upon an existing model-based effort to develop a holistic view of the Bay-Delta-River-Watershed system. CASCaDE I developed a set of linked models to assess Delta ecosystem response to climate change. In CASCaDE II, we propose to refine and extend those modeling capabilities to assess Delta ecosystem response to changes in climate and physical configuration. With a new state-of-the-art hydrodynamic and sediment model at its core, CASCaDE II will link models of climate, hydrology, hydrodynamics, sediment, geomorphology, phytoplankton, bivalves, contaminants, marsh accretion, and fish. Our goals are to apply these linked models to 1) better understand Delta ecosystem function, 2) assess possible futures of the Delta under scenarios of climate and structural change, and 3) provide science-based information to support the DSC in its co-equal goals of water supply and ecosystem protection. The tools developed will provide an objective basis for anticipating and diagnosing Delta ecosystem responses to planned and unplanned changes. Experiments using the linked models are designed to address questions such as: How will climate change, together with new conveyance structures or increased flooded island habitat, alter water flow and drinking water quality? With projected changes in residence time, turbidity, temperature, and salinity, how will primary productivity, invasive bivalves, marsh processes, contaminant dynamics, and fish populations respond?
    Science topics None specified
    Updated April 29, 2022
  • Title

    Quantifying the contribution of tidal flow variations to survival of juvenile Chinook salmon

    Lead U.S. Geological Survey [USGS]
    Description The purpose of this project is to quantify how tides in the Delta influence survival of juvenile salmon. Juvenile salmon survival increases when there is more flow and the river is less tidally influenced. We hypothesize that the increase in survival is because of reduced travel times causing less exposure to predators. This project will test this hypothesis using multiple models including ones that can predict how management actions that modify tidal patterns affect juvenile salmon survival.
    Science topics Chinook Salmon, Salmon migration, Surface water / flow, Tides, Water management
    Updated January 29, 2024
  • Title

    Assessing Sediment Nutrient Storage and Release in the Delta: Linking Benthic Nutrient Cycling to Restoration, Aquatic Vegetation, Phytoplankton Productivity, and Harmful Algal Blooms

    Lead U.S. Geological Survey [USGS]
    Description Nutrients in sediment play a large role in influencing food webs, harmful algal blooms, aquatic vegetation, and drinking water quality. This study will investigate the amount, types, and dynamics of nutrients in Delta sediments. It will also examine sediment microbial communities that mediate these processes. Results of this study will help determine how the planned reduction in nutrient inputs to the Delta will effect sediment nutrients and microbial communities following the upgrade of the Sacramento Regional County Sanitation District’s wastewater treatment plant. Data will also inform how wetland restoration and invasive aquatic vegetation influence sediment nutrients and microbial communities. These data will contribute to improving computer models that inform large-scale nutrient management actions.
    Science topics Aquatic vegetation, Benthic, Cyanobacteria, Harmful algal blooms HAB, Nitrogen, Nitrogen / ammonia, Nutrients, Phytoplankton, Sediments
    Updated May 14, 2024
  • Title

    Next Generation Multi-Hazard Levee Risk Assessment

    Lead University of California - Los Angeles [UCLA]
    Description In June 2004, a 350-foot levee section gave way west of Stockton, flooding crops and more than a dozen homes, and challenging state officials to protect the state's water supply. What is the risk of that happening again somewhere in the Delta? In light of agricultural fields sinking, the sea level rising, more frequent and severe floods occurring, and earthquakes looming, improvements are estimated to cost $3.8 - $4.3 billion over the next few decades. This study combines 3-D representations with information on the levee’s structure to analyze how different levees respond to floods, sea level rise, and earthquakes. State officials released the last Delta Risk Management Strategy a decade ago. Since then, scientists have collected significant amounts of data and have developed new procedures to compute the risk of failure. This work will produce new Delta-wide data sets important for characterizing the hazards coming from floods and earthquakes. It will also develop the best method to conduct levee hazard assessments. Applying this new method will ensure wise investments and effective threat mitigation Delta-wide.
    Science topics None specified
    Updated April 29, 2022
  • Title

    Tidal Wetland Restoration in the Bay-Delta Region: Developing Tools to Measure Carbon Sequestration, Subsidence Reversal, and Climate Resiliance 2021

    Lead California State University [CSU]
    Description Tidal marshes are important ecosystems in the San Francisco-Bay Delta. They remove carbon from the atmosphere, build up soils that buffer our communities from sea level rise, mitigate excessive nutrients (like nitrogen), and provide critical habitat and food resources for a diversity of species. It is difficult to predict how tidal marshes change naturally over time versus as a response to climate change, restoration and water quality changes. This project provides the first ever multi-year dataset of the complete carbon budget of a tidal marsh. This dataset will be used to predict seasonal and annual carbon budgets in tidal marshes over a range of salinities. The model will assess the sustainability of existing and potential restored tidal wetland benefits over the next 100 years using remote sensing data. The model will be an open-source tool designed for use by wetland managers and decision makers in the Bay-Delta region. This project supports ongoing initiatives to restore tidal wetlands in the Delta and our ability to manage them in a changing world.
    Science topics None specified
    Updated April 29, 2022
  • Title

    An Improved Genomics Tool for Characterizing Life History Diversity and Promoting Resilience in Central Valley Chinook Salmon

    Lead Michigan State University
    Description This study will improve our ability to protect the diversity of traits in Chinook salmon. The diversity of Chinook salmon migration timing is decreasing in the Central Valley. A key roadblock to protecting diversity is the current inability to rapidly and inexpensively identify large numbers of individuals from different populations during their migration to the ocean. This study addresses this information gap by leveraging pre-existing genomic data to develop a new technique that will allow scientists to identify individuals to life history type and location. For example, this study will potentially be able to identify Fall Run Chinook that are from the Sacramento versus the San Joaquin River basins. This information, in combination with data on water temperature and river flows, can determine the relationship between environmental conditions and juvenile salmon life history diversity. The information generated by this work will provide managers with the ability to accurately monitor the effect of key management actions on the different Central Valley Chinook salmon populations.
    Science topics Chinook Salmon, Estuaries, Fish, Habitat restoration, Resilience, Salmon rearing
    Updated November 29, 2022
  • Title

    Impact of Temperature and Contaminants on Chinook Salmon Survival: A Multi-Stressor Approach

    Lead National Marine Fisheries Service [NMFS]
    Description The decline of native salmon species has resulted in their protection under the U.S. Endangered Species Act and the California Endangered Species Act. Disease and predation are primary drivers of mortality as salmon migrate. Multiple stressors, such as exposure to contaminants and elevated temperature, can impact rates of disease and predation of salmon as they migrate to the ocean. This study examines how contaminant exposures at different temperatures affects salmon health. Specifically, the study investigates the sensitivity of salmon to a contaminant mixture of bifenthrin (a pyrethoid pesticide) and triclosan (an antibacterial added to personal care products). Both contaminants can alter fish swimming behavior and critical physiological functions. Similarly, temperature stress can impact fish physiology and behavior, as well as exacerbate the adverse effects of contaminants.
    Science topics None specified
    Updated April 29, 2022
  • Title

    An Evaluation of Sublethal and Latent Pyrethroid Toxicity Across a Salinity Gradient in Two Delta Fish Species

    Lead Oregon State University
    Description Pyrethroids are a type of insecticide frequently detected in the San Francisco Bay and Delta (SFBD). They are highly toxic to fishes and may contribute to their decline. The Central Valley Water Resources Control Board has adopted regulations for many pyrethroids. These concentration goals for Delta surface waters are quite stringent. However, they do not take into account non-lethal effects in fishes, particularly during the early life stages and at the salinity conditions we see in the SFBD. Understanding non-lethal effects in fish is vital to influencing population health. This study investigates pyrethroid toxicity on Delta smelt and Inland Silverside embryos, while accounting for changing SFBD salinity and other factors such as sediment. Results will inform the development of pesticide regulation criteria and control efforts, furthering the protection of SFBD fishes.
    Science topics None specified
    Updated April 29, 2022
  • Title

    Changes in Organic Carbon and Food Resources in Response to Historical Events in the Sacramento-San Joaquin Delta: A Synthesis Project

    Lead Virginia Institute of Marine Science
    Description Recent management strategies in the Delta rely on habitat restoration and water quality improvement to restore ecosystem function. However, current monitoring programs have been limited in their ability to measure ecosystem functions such as food webs. This study explores changes to the sources, quantity, and quality of organic carbon that support the Delta food web. Data from fifteen sites selected to represent the dominant sub-habitats in the Delta will identify the available food resources. The project examines how food resources are affected by wastewater treatment and habitat restoration. Information about organic carbon in the historic and current Delta will aid in establishing realistic goals and targets for ongoing and future restoration efforts in the Delta.
    Science topics None specified
    Updated April 29, 2022
  • Title

    Integrated Science and Management of Nutrient, Salt, and Mercury Export from San Joaquin River Wetland Tributaries to the Delta

    Lead University of California - Merced [UC Merced]
    Description Mercury, salinity, and nutrients such as nitrogen and phosphorus are major contaminants of concern and are an understudied source of water quality impairment to the Delta. This study will (1) examine seasonal variation and transfer of salt, nutrients, and mercury out of managed wetlands;(2) establish and verify whether other routinely monitored water components can serve as reliable alternatives (proxies) for detecting mercury and nutrients;(3) integrate monitoring data and proxy relationships to estimate levels of contaminants;and (4) develop science-based strategies for adaptive co-management of salt, nutrients, and mercury from seasonal wetlands to improve water quality in the Delta. Outcomes from this study will provide improved best practices and guidelines for management of salt, nutrients, and mercury in wetlands. Results will also address key knowledge gaps identified in the Delta Nutrient Research Plan and provide support for the Delta Mercury Control Plan.
    Science topics Nutrients, Salinity, Hg and methyl mercury
    Updated April 29, 2022
  • Title

    CASCaDE: Computational Asessments of Scenarios of Change for the Delta Ecosystem

    Lead U.S. Geological Survey [USGS]
    Description Agencies of the CALFED Bay-Delta Authority (CBDA) face tough decisions as they search for strategies to meet their programmatic goals of stabilizing water supplies in California, providing safe drinking water to a growing population, and sustaining diverse populations of native species and their supporting ecosystem functions. The challenge of finding balanced solutions to these goals is daunting because of the enormous complexity of the San Francisco Bay-Delta system and its tributary rivers and their watersheds. The challenge grows as we consider the additional layer of complexity imposed by the certainty that all the key forces that drive dynamics of this ecosystem (climate, hydrology, water management, land use, sea level) will change significantly in future decades. This proposal describes a model-based approach for developing a long view of the Bay-Delta-River-Watershed system. The long view will be developed through simulations with linked models to project changes under a range of plausible scenarios of global warming, hydrologic responses, land-use change, reconfigurations of within-Delta habitats, and sea level rise. Our goals are to develop and apply a model-based approach of ecological forecasting to project future states of the Delta ecosystem under prescribed scenarios of change, and to communicate the outcomes of those scenarios to resource managers facing the daunting challenge of meeting CBDP goals in a continually changing world.
    Science topics None specified
    Updated November 18, 2022
  • Title

    The effect of temperature on predation of juvenile salmonids

    Lead University of California - Davis [UC Davis]
    Description This study will investigate fish swim performance in response to temperature, using salmon and two of its known predators: largemouth bass and Sacramento pikeminnow. The researcher will assess swim performance metrics and predation risk inside and outside the ideal thermal range of each species to determine if a temperature advantage predicts salmon survival in predation scenarios. This project’s results will provide a mechanistic understanding of how temperature stress may influence mortality risk of juvenile Chinook salmon through predation, which will offer a more holistic perspective on the management of this species
    Science topics Temperature
    Updated April 29, 2022
  • Title

    Nitrogen cycling and ecosystem metabolism before and after regulatory action

    Lead Stanford University
    Description This project focuses on nitrogen and carbon cycling within the Bay-Delta, both before and after planned 2021 upgrades to the Sacramento Regional Wastewater Treatment Plant (SRWTP). We will measure in situ benthic nitrate (NO3- ) and oxygen (O2) fluxes using a new non-invasive technique, which provides high frequency continuous data over a much larger sediment surface area than traditional methods. The SRTWP currently represents one of the largest point sources of nitrogen to the Bay-Delta, with the upgrades projected to cut nitrogen outputs from the plant by ~65%. This project will help assess the efficacy of this major management action and our results will add to biogeochemical models for the Bay-Delta.
    Science topics Nitrogen / ammonia
    Updated April 29, 2022
  • Title

    Survivial and Migratory Pattern of Central Valley Juvenile Salmonids

    Lead University of California - Davis [UC Davis]
    Description The purpose of this project is to determine the survival and movement patterns of late-fall Chinook salmon smolts and steelhead smolts as they migrate downstream. This information is important to better understand how salmon move through the system.
    Science topics None specified
    Updated April 29, 2022
  • Title

    The Role of Microcystis Blooms in the Delta Foodweb: A Functional Approach

    Lead San Francisco State University [SFSU]
    Description We propose a collaborative investigation of blooms of the toxic, cyanobacteria Microcystis in the San Francisco Estuary Delta including how blooms develop, identification of toxic species and strains, controls on toxin production, and foodweb effects. The research will address Delta Science Program Priority Research Topic 2 and Research Topic 5 in the CALFED-funded analysis of ammonium issues in the Estuary. The appearance of Microcystis in the Delta was coincident with the POD, suggesting a link. The spatial and temporal scales of Microcystis blooms was identified with their environmental covariates but a mechanistic analysis of the conditions that distinguish bloom periods and locations, which are critical for ecosystem modeling and management, are still lacking. Our objectives are to determine: 1- the biotic and abiotic factors controlling Microcystis bloom formation and toxin production;2- how Microcystis strains and microbial associations influence toxicity;3- the role of Microcystis in the Delta pelagic food web and its effect on the POD through zooplankton grazing. Our 3-year work plan comprises 2 years of laboratory and field work (contrasting bloom and non bloom locations). Experiments will be conducted to determine mechanisms driving observed in situ patterns. We will synthesize the results and clarify the environmental-bloom-food web effects in a useable format for management efforts aimed towards water supply, fisheries and recreational use of the Delta.
    Science topics Harmful algal blooms HAB
    Updated April 29, 2022
  • Title

    Phytoplankton Communities in the San Francisco Estuary: Monitoring and Management using a Submersible Spectrofluorometer

    Lead California Department of Water Resource [DWR]
    Description The purpose of this project is to evaluate a new submersible spectrofluorometer, the bbe FluoroProbe, for phytoplankton monitoring and management in the SFE. Secondly, this project seeks to investigate high-frequency patterns in spatial phytoplankton group distributions among Delta habitats and along gradients from the western Delta and northern San Francisco Bay.
    Science topics None specified
    Updated April 29, 2022
  • Title

    Modeling the Delta Smelt Population of the San Francisco Estuary

    Lead San Francisco State University [SFSU]
    Description The purpose of this project is to develop an individual-based particle-tracking model examining population behavior of Delta smelt under different scenarios.
    Science topics Delta Smelt
    Updated April 29, 2022
  • Title

    Biomass and Toxicity of a Newly Established Bloom of the Cyanobacteria Microcystis aeruginosa and its Potential Impact on Beneficial Use in the Sacramento-San Joaquin Delta

    Lead California Department of Water Resource [DWR]
    Description Monitoring and simple analysis of the extent of this cyanobacteria in the Delta, and preliminary exploration of the impacts of cystins on drinking water quality, and human and wildlife health.
    Science topics None specified
    Updated April 29, 2022
  • Title

    Suisun Marsh Salinity Control Gate Study

    Lead California Department of Water Resource [DWR]
    Description Description Suisun Bay and Marsh are a key part of the habitat for Delta Smelt, but during drier periods such as summer, Delta Smelt may be at least partially excluded from Suisun Marsh due to high salinities. The purpose of this proposal is to provide scientific support a management action for Smelt, operation of the Suisun Marsh Salinity Control Gates (SMSCG). This facility is currently to tidally pump water into the Marsh to improve fall and winter habitat conditions for waterfowl, but could also provide a tool to manage aquatic habitat for Delta Smelt in other periods. Specifically, by using the SMSCG to direct more fresh water in Suisun Marsh, our prediction is that reduced salinities will improve habitat conditions for Delta Smelt in the region. Need The status of Delta Smelt is dire. As part of the Resources Agency's Delta Smelt Resiliency Strategy, in August 2018 we conducted pilot operations of the SMSCG to support Delta Smelt , with promising results. Based on this early success, we expect that the SMSCG will be used as a seasonal tool to support Delta Smelt in summer-fall in coming years as part of the coming FWS Biological Opinion and DFW ITP. Neither has been completed, but SMSCG operations for fish are expected to be required in each. Hence, the proposed study is intended to provide a scientific evaluation and guidance for an expected SMSCG action in 2020. Objectives The primary objective of this project is to evaluate the effectiveness of the SMSCG action. Questions to be addressed include: • Did the action improve habitat conditions for Delta Smelt in the Suisun Region? • Does the Suisun Region typically have better habitat and food web conditions than the upstream River Region? • Do Delta Smelt respond favorably to the SMSCG flow action? • Does operation of the SMSCG affect other fishes and clams?
    Science topics Salinity
    Updated April 29, 2022
  • Title

    North Delta Flow Action: Role of Improved Yolo Bypass Flows on Delta Food Web Dynamics

    Lead California Department of Water Resource [DWR]
    Description Description In a collaborative effort between CA Department of Water Resources, US Bureau of Reclamation, CA Department of Fish and Wildlife, United States Geological Survey, San Francisco State University, and UC Davis, this study will investigate the role of augmented summer and fall flows in the Yolo Bypass and North Delta areas on lower trophic food web dynamics and the benefits to listed fish species. Using both continuous and discrete sampling approaches, this study will relate hydrologic patterns to chlorophyll-a, nutrients and primary productivity, plankton densities and composition (phytoplankton and zooplankton), contaminant concentrations, as well as water quality parameters such as electrical conductivity, turbidity, temperature, and dissolved oxygen. In addition, caged hatchery Delta Smelt will be monitored to determine the effects of the managed flow action and increased food web productivity on fish survival, growth, and behavior. Need Due to the food-limited nature of the San Francisco Estuary, it is critical to understand mechanisms that result in successful food web productivity including phytoplankton blooms. Food limitation is one of the primary hypothesized causes of the Pelagic Organism Decline. In 2011 and 2012 there was evidence that a moderate Yolo Bypass flow pulse during fall agricultural drainage periods was followed by phytoplankton blooms in the lower Sacramento River. Managed flow actions in the following years showed an increase in food web productivity could be repeated;however, results varied across years and flow actions indicating more research is warranted to understand correlations between flow and abiotic conditions, and the biological response of the food web. The increases of summer/fall flows in North Delta, has been considered a management strategy as part of complying with USFWS Delta Smelt Biological Opinion Action 4. The augmentation of flows through the Yolo Bypass/North Delta is also included as one of several Delta Smelt Resiliency Strategies by Natural Resources Agency. Objectives • Determine if managed flow actions through the Yolo Bypass stimulate increased primary productivity locally and downstream, and if it is repeatable. • Characterize how nutrients, chlorophyll and plankton (composition and density) in the Toe Drain, Cache Slough Complex, and lower Sacramento River change in response to flow pulses. • Determine if nutrient subsidies of the source water and downstream are limited by abiotic and biotic factors. • Characterize spatial differences and transport of pesticide contaminants in the Yolo Bypass in response to the flow actions. • Determine survival, growth and behavior of caged hatchery Delta Smelt before and after the flow action in the Yolo Bypass.
    Science topics Flows, Water management
    Updated April 29, 2022
  • Title

    Impact of Temperature and Contaminants on Chinook salmon survival: A Multi‐Stressor Approach

    Lead National Oceanic and Atmospheric Administration [NOAA]
    Description This project will examine how contaminant exposures at different temperatures impact a number of critical physiological functions and the associated genes that maintain salmon fitness. The project will determine the sensitivity of fall‐run Chinook salmon to a mixture of bifenthrin, a pyrethoid pesticide, and triclosan, an antibacterial added to personal care products, at optimal and high temperatures that Chinook salmon encounter during their outmigration through the Sacramento and San Joaquin rivers. The hypothesis is that these stressors will impact salmon predator and disease susceptibility and will interact, such that the cumulative effect on salmon could not be predicted from multiple single exposures. To test the hypothesis, fall‐run Chinook salmon parr will be exposed to sublethal concentrations of bifenthrin, triclosan, and a mixture of bifenthrin and triclosan at different temperatures. The impacts of these exposures on salmon will be assessed with the following endpoints: (1) predator susceptibility through altered response latencies and escape velocities;  (2) disease susceptibility in response to a disease challenge; and (3) differential gene expression by high‐throughput sequencing of the Chinook salmon transcriptome.
    Science topics Pesticides
    Updated September 28, 2023
  • Title

    Assessing sea-level rise and flooding changes in the Sacramento/San Joaquin Delta using historical water-level records

    Lead California State University [CSU]
    Description The project aims to recover, digitize, and analyze more than 1300 station years of ‘lost-and-forgotten’ water level records collected from 1857 to 1982 in the Sacramento-San Joaquin Delta. These measurements, augmented by modern data, will improve our understanding of tidal, flood, and sea level trends in the system. By determining ‘hotspots’ of habitat and flood risk sensitivity, the results may be used to better focus future scientific and management priorities, to protect the environment, manage flood risk, and enhance community resilience to climate change
    Science topics Backwater, Climate change, Environmental drivers, Estuaries, Land elevation, Levees, Outflow, Sea level rise, Stage, Subsidence, Surface water / flow, Tides, Velocity, Vessels and shipping channels, Water, Wind
    Updated October 10, 2023
  • Title

    From Microbes to Zooplankton, What Defines a Beneficial Wetland?

    Lead San Francisco State University, Estuary & Ocean Science Center
    Description Our study will characterize species diversity at multiple levels of biological organization in the water column of restoring wetlands in the upper San Francisco Estuary and Delta (SFE), from bacteria to fishes. In doing so, we will also describe the foodweb benefits being provided to larval fishes, including longfin smelt, through additional dietary DNA analysis. We will use the species diversity we find in the water column to identify a subset of biota that are indicative of the conditions present in wetlands in different stages of restoration (early, intermediate, and mature) and identify connections between those indicators to the foodweb resources being provided to higher trophic levels. We will study 3-4 wetlands in each of 3 stages: early (unvegetated), intermediate (partially vegetated and partially channelized), and mature (fully vegetated and channelized) wetlands.
    Science topics Crustaceans, Cyanobacteria, Estuaries, Fish, Food webs, Habitat, Habitat restoration, Insects, Invertebrates, Longfin Smelt, Other species, Other zooplankton, Pelagic fish, Phytoplankton, Predation, Restoration, Salinity, Saltwater / freshwater marshes, Tidal wetlands, Wetlands, Zooplankton
    Updated January 31, 2024
  • Title

    Impacts of predation and habitat on Central Valley Chinook smolt survival

    Lead University of Vermont, USGS Vermont Cooperative Fish and Wildlife Research Unit
    Description The Sacramento River in California’s Central Valley has been highly modified over the past 150 years due to mining, urbanization, and impoundment/diversion of river flow to provide water for municipal, industrial, and agricultural needs. Land use changes combined with high levels of harvest have been accompanied by drastic declines in native salmon populations, including the once abundant Chinook salmon (Oncorhynchus tshawytscha). Further, the region has been subject to the introduction and widespread establishment of non-native fish species, some of which are predators of juvenile salmon. Of the four historic ecotypes of Chinook salmon (fall, late-fall, winter, and spring runs), winter- and spring-runs have been most impacted and are currently listed as endangered and threatened respectively under the US Endangered Species act. Past research has illustrated how smoltification of juvenile salmon and outmigration from freshwater to the ocean is a time of increased mortality, and reduced survival at this life stage can impact the number of reproducing adults returning to the system in subsequent years. While these studies have provided valuable information on how habitat and environmental conditions experienced by migrating Chinook salmon smolts can affect survival, they have primarily focused on individual ecotypes during the portion of the year where downstream migrations occur. However, variation in smolt size and migration timing among ecotypes can expose migrating fish to differing environmental conditions and levels of exposure to predation, which can present distinct risks for outmigration survival. To identify the areas and environmental conditions which have the greatest relative impact on juvenile survival for each ecotype, this project will use over ten years of data (2012-2022) from acoustically tagged smolts representing all four Chinook salmon ecotypes in the Sacramento River/Central Valley. Combining these data will increase sample size relative to previous studies, the range of environmental conditions (e.g., temperature, flow, and predator abundance) modeled, the range of fish sizes, and thus, the statistical power of our analyses. We hypothesize that each ecotype will have different factors that will be the primary drivers of mortality experienced during outmigration. To test our hypotheses, we will implement Cormack-Jolly-Seber (CJS) mark-recapture models to estimate both the probability of survival through reaches of the Sacramento River delineated by acoustic receivers, and the detection probability in each reach. Survival will be modeled as a function of individual, release group, reach-specific, and time-varying covariates. Further, to examine the relative impact of predation on smolt survival, we will include an additional covariate representing predator-prey encounter rates using the Mean Free-path Length model. Finally, model selection will be applied to a series of CJS models to assess the relative impact of each covariate on smolt survival for each of the four Chinook ecotypes.
    Science topics Chinook Salmon, Environmental drivers, Fish, Flows, Habitat, Predation, Salmon migration, Water temperature
    Updated February 2, 2024
  • Title

    White Sturgeon Telemetry Synthesis

    Lead Cramer Fish Sciences
    Description Acoustic telemetry studies are expensive and logistically demanding. A new study to tag and monitor 315 White Sturgeon would require a massive field effort by a large team, but by pooling and leveraging existing datasets, this sample size and analysis will be achieved at a fraction of the cost and effort. In recognition of the efficiencies gained by this approach, the Delta Stewardship Council’s Science Program lists the synthesis and analysis of existing telemetry datasets in Science Action Area (SAA) 2. This project directly addresses SAA 2 by capitalizing on existing White Sturgeon telemetry data through the synthesis of three existing large telemetry dataset to understand system-wide White Sturgeon movements. This contract will synthesize existing long-term acoustic telemetry datasets in order to address high priority research questions for the management of White Sturgeon in the San Francisco Estuary system. These questions include: 1. What is the periodicity of spawning migrations by tagged White Sturgeon, and how do these estimates compare to those from previous, single-basin studies? 2. What is the scope and variability of inter-basin movements exhibited by tagged adult White Sturgeon across years? 3. Is there individual fidelity to specific migration routes or sites within each river basin? 4. Do White Sturgeon migrating through the Yolo Bypass experience delays in reaching spawning grounds relative to fish using the mainstem Sacramento River or San Joaquin River routes? 5. Is the onset of upstream migration movement by individuals associated with a characteristic flow rate or event? This contract will serve as a model for future telemetry synthesis studies by adhering to best practices in scientific computing for reproducible, transparent research, and by making all parts of the data and analysis accessible to the broader Delta research community.
    Science topics Environmental drivers, Fish, Flows, White Sturgeon
    Updated May 21, 2024
  • Title

    Continuous Flow and Water Quality Monitoring Network in the Sacramento-San Joaquin Delta

    Lead U.S. Geological Survey [USGS]
    Description This project envisions the continuation, expansion, and further integration of high frequency monitoring for flow, water quality (including chlorophyll and nutrients), sediment, as well as biological responses at key locations in the Delta and Suisun Bay. The physical properties monitored by the fixed-station network are the primary drivers of the habitat conditions and biological responses that management actions hope to achieve. Nutrient dynamics are explicitly measured at select stations to improve our understanding of how physical dynamics, water quality and landscape features shape the base of Delta food webs. These data will provide information about drivers linked to food quantity and quality as well as potential toxins production by harmful algae. Suspended-sediment monitoring provides an understanding of the inputs and internal exchanges between regions, locations of sources and sinks, and provides insight into the underlying cause of turbidity variability in the study area. Suspended-sediment measurements gage the availability of suspended sediment for existing marshes and for proposed large-scale marsh restoration efforts in the Delta. There are a total of 5 sub-tasks in this project: • Task 1: Hydrodynamics Team – Fixed Station Network Operation and Maintenance • Task 2: BioGeoChemistry Team -- Fixed Station Network Operation and Maintenance • Task 3: Delta Sediment Team – Fixed Station Network Operation and Maintenance • Task 4: Bay Sediment Team – Fixed Station Network Operation and Maintenance • Task 5: Project Management
    Science topics Chlorophyll A / B, Conductivity, Dissolved oxygen, Flows, Nutrients, pH, Phytoplankton, Sediments, Stage, Surface water / flow, Tides, Turbidity, Velocity, Water operations / exports, Water temperature
    Updated January 19, 2024
  • Title

    The Relative Contributions of Contaminants to Ecological Risk in the Upper San Francisco Estuary

    Lead Delta Stewardship Council - Delta Science Program
    Description This project developed methods to calculate risk of mixtures of pesticides for the Upper San Francisco Estuary (USFE). We used curve fitting to estimate the exposure-response curves for each individual chemical and then the mixture. For the mixtures, the models were normalized for specific ECx values. In that way, the curve fitting was optimized for effects that are comparable to most threshold values. A Bayesian network was built that incorporated five different pesticides and mercury. The input distributions of the contaminants were measured amounts from each of the six risk regions. We also explored three different methods of combining the results of the three pathways – additive, average, and expert judgement. The initial result was the BN model’s Predicted Fish Mortality (%). The Sensitivity analysis (mutual information) identified the most important components of the Bayesian network in determining the toxicity. The top two pathways were the Malathion/Diazinon Mortality pathway and the Mercury Mortality pathway. For the individual nodes Mercury, Bifenthrin and Season were key. Currently, we are completing the risk assessment network by adding Chinook salmon and Delta smelt population pathways to estimate risk to the six Risk Regions. A major accomplishment was the demonstration that curve fitting using additive models for mixtures can be used to estimate fish toxicity in this proof-of-concept model. Bifenthrin, the specific risk region, and season were the inputs that were most important to the calculation. Factors determining macroinvertebrate community structure were identified using multivariate tools. Water quality parameters were the most important in determining clusters of similar macrobenthic communities. Because contaminants were not statistically significant in determining these patterns, further analysis of macroinvertebrate community structure was postponed. At this time, the techniques applied in this program appear applicable to estimating risk due to the variety of chemicals and other stressors to the multiple endpoints under management in the USFE.
    Science topics None specified
    Updated January 24, 2024
  • Title

    Carbon Biogeochemical Cycling in Tidal Wetlands: Exploring Lateral Carbon Exchange and Sequestration Potential

    Lead University of California - Berkeley [UC Berkeley]
    Description Tidal wetlands, at the interface of land and ocean, play a critical role in carbon biogeochemical cycling and have the potential to provide major feedback to the Earth system through greenhouse gas exchange and long-term carbon sequestration. However, the efficiency of carbon sequestration in tidal systems relies on both vertical carbon exchange with the atmosphere and lateral tidal exchange with adjacent water bodies. Unfortunately, the importance of hydrologic carbon fluxes has been largely overlooked, leaving a crucial aspect of coastal wetland net carbon balance unaddressed. We employed an integrated approach to quantify vertical and lateral carbon exchange and studied their dynamics, combining eddy covariance flux measurements with on-site water quality and tidal discharge measurements, as well as manual 24h surface water samplings. Our measurements were conducted in a recently restored tidal freshwater marsh in the Sacramento-San Joaquin Delta, CA, that stands out in global networks like FLUXNET and Ameriflux owing to its impressive net ecosystem exchange of -850 g C m-2 yr-1. Using wavelet decomposition, we examined the variability of carbon exchange (CO2 and CH4) across different timescales. Through information theory and mutual information analysis, we assessed the factors influencing both vertical and lateral exchanges. Our preliminary findings suggest that variability in carbon exchange is largest at the diel scale, with plant gross primary productivity and tidal fluctuations in depth having the most significant interactions with CO2 and CH4 fluxes, respectively. Furthermore, our tidal cycle samplings revealed that dissolved inorganic carbon dominates the fraction of lateral carbon loss, accounting for approximately 80% of the export. Remarkably, similarities existed between the values for net lateral carbon export and ecosystem respiration, signifying that the dissolved, terrestrial-to-ocean carbon flux could represent one of the primary fates of the fixed carbon in this tidal ecosystem. These large dissolved inorganic carbon fluxes and their chemical speciation, are important to consider when estimating the climate mitigation potential of restored tidal wetlands.
    Science topics Carbon, Carbon storage, Greenhouse gas GHG
    Updated January 30, 2024
  • Title

    Pixel-Wise Footprint Analysis of GPP Using High-Resolution NDVI/NIRv Data

    Lead University of California - Berkeley [UC Berkeley]
    Description Spectral indices such as NDVI have long been found to be good predictors of plant productivity at many spatial scales from the canopy to the landscape. Spectral indices are an important tool for upscaling GPP fluxes we measure at the ecosystem scale through Eddy Covariance up to larger spatial scales. Other indices, such as NIRv (expressed as NDVI * total NIR) have also been shown to be potentially more accurate predictors of GPP using in-situ spectral measurements than NDVI alone. Additionally, associating spectral signals within modeled flux footprint areas has been shown to improve the predictive capability of spectral indices compared to estimates using remotely sensed data centered directly on top of flux towers. Most if not all of these spatially explicit footprint analyses have been done by aggregating footprints into polygons based on their 50%-90% estimated flux contributions, and then associating those polygons with fluxes and spectral signals within them. This approach has been necessary largely because of the spatial scales involved with satellite remote sensing products, reaching a practical minimum of 3m, downsampled from 4.8m imagery by Planet Labs. By combining pixel-weighted flux footprint contributions with ultra-high resolution (3cm) spectral drone data, we will examine and compare how different spatial scales and indices affect the capability of spectral data to predict fluxes which are not directly measured.
    Science topics None specified
    Updated January 30, 2024
  • Title

    Monitoring Sacramento River winter-run Chinook salmon life history diversity, growth, and habitat use among varying hydroclimatic regimes

    Lead University of California - Berkeley [UC Berkeley]
    Description Sacramento River winter-run Chinook salmon have been endangered since 1994. Historically, the fish spawned during summer in cool tributaries upstream of Sacramento, but dams have limited spawning habitat to a small reach of the river. Today, survival of their offspring is heavily dependent on cool summer water releases from reservoirs, which also provide critical water supplies for irrigation, municipal, and industrial needs, as well as providing flood control and hydropower generation. During drought, this can lead to difficult management decisions. Understanding how winter run Chinook salmon respond to drought and water temperature is therefore vital to the management of this endangered population. This project tackled two outstanding questions about winter-run salmon ecology. The first was how winter-run Chinook use different rearing habitats during drought and non-drought periods, and the second was to explore which habitats provide enhanced growth during drought and non-drought periods. To answer these questions, UC Berkeley post-doc Pedro Morais used isotopic analysis of otoliths, or fish ear bones, which grow continuously throughout their lives and therefore carry a record of their environment and growth. Using otoliths, researchers can reconstruct details of fishes’ lives, including water temperature and migration patterns.
    Science topics None specified
    Updated February 1, 2024
  • Title

    Defining the architecture and recurrence interval for faults in the Sacramento-San Joaquin Delta: Assessing Potential Geohazards

    Lead San Diego State University
    Description This project aimed to create a detailed fault map for the Sacramento-San Joaquin Delta by mapping the faults throughout the Delta waterways. The project began with a review of existing data and reports, then a high-resolution seismic reflection and sidescan sonar survey, and finally, collection/analysis, including radiocarbon dating, of sediment cores to create the first detailed fault maps for the Delta waterways. The project worked to constrain the significant rupture histories of the Kirby Hills and Midland Faults, which is important for understanding the potential of future earthquakes.
    Science topics Landscape change, Seismicity
    Updated March 7, 2024