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  • Title

    Effects of drought and elevated nutrients on invasion by Lepidium latifolium and implications for carbon storage in tidal wetlands of the San Francisco Bay- Delta

    Lead Delta Stewardship Council - Delta Science Program
    Description The Delta ecosystem is under threat from multiple concurrent stressors, including drought, nutrient pollution, and invasion by non-native species. Lepidium latifolium is an invasive peren- nial plant that displaces native species and may reduce carbon storage in tidal marshes. Preliminary data suggest that drought may be detrimental to L. latifolium invasion, whereas elevated nutrients may promote invasion. Using experimental manipulation of tidal marsh plots, this project will test the impact of drought and elevated nutrients on the invasion of L. latifolium. The results will inform management of L. latifolium in the Bay Delta by identifying its vulnerabilities to climatic and nutrient conditions, and will be shared with management agencies including East Bay Regional Parks, San Pablo Bay National Wildlife Refuge, and Palo Alto Baylands, among others. The results will also be integrated with the PI’s dissertation research on the carbon storage capacity of L. latifolium, in order to inform wetland carbon offset policies.
    Science topics None specified
    Updated December 21, 2023
  • Title

    Large and small-scale sediment dynamics during (after) the drought

    Lead Delta Stewardship Council - Delta Science Program
    Description Turbidity plays a key role in Delta aquatic ecosystems, where suspended sediment can limit light for phytoplankton growth, transport contaminants, provide protection from predation for many fish species, and contribute to natural sediment recovery in shallow water habitats. The impact of drought conditions on water quality and ecological health is not well studied in estuarine systems, and more information is needed to manage the impacts of California’s drought and recovery in the Delta. This project will examine the effects of drought conditions on turbidity, particularly the interplay between estuarine turbulence, suspended sediment flocculation (particle aggregation), and in-water light levels. Information from this project will contribute fundamental knowledge on flocculation dynamics, help identify critical points for turbidity control during drought, and improve modeling and predictions of sediment transport within the Delta.
    Science topics None specified
    Updated January 4, 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 November 12, 2025
  • Title

    San Francisco Bay-Delta Estuary 2025 Lidar Mapping Collaboration

    Lead San Francisco Estuary Institute [SFEI]
    Description

    This lidar project provides high-resolution, region-wide elevation data for the San Francisco Bay-Delta Estuary, offering an unprecedented view of the landscape, landforms, and habitat conditions. LiDAR, which stands for Light Detection and Ranging, uses laser pulses to measure the distance between the sensor and the ground, creating detailed three-dimensional maps of terrain. This dataset captures fine-scale features across the San Francisco Bay-Delta Estuary. This supports researchers, community members, and agencies to better visualize changes in topography, habitat distribution, and flood risk. By providing consistent, accurate, and comprehensive coverage, the lidar data supports a wide range of applications. Researchers can use the data to study habitat dynamics, track landscape change over time, model ecological processes, and more. Agencies and planners can integrate the information into flood risk management, infrastructure planning, and climate adaptation strategies. Community organizations and local stakeholders can also use the data to understand environmental conditions in their neighborhoods and inform local projects. The lidar data will be made publicly available following final review in 2026. 

    Availability details and links will be shared here as soon as the data are released. 

    This lidar collection collaboration would not be possible without funding support from the Wetlands Regional Monitoring Program (through funding awarded by the San Francisco Bay Restoration Authority), Delta Stewardship Council, California Department of Water Resources, South Bay Salt Pond Restoration Project, and Valley Water (Santa Clara County). 

    Project Details:

    Area

    ~1.25 million acres (the size of Delaware)

    Timing

    Coordinated with low tides

    Aircraft

    Cessna Caravan

    Sensor

    Riegl VQ-1560ii-S

    Accuracy

    Precise to ~12 cm (height of a soda can!)

    Quality

    Q1 (last LiDAR collection in 2017 was at Q2)
    Science topics None specified
    Updated March 2, 2026