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  • 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

    Pesticide risk analyses and management actions, chemical fate and transport

    Lead University of California - Santa Barbara [UCSB]
    Description This project work will model the risk of pesticide pollution in 225 sub-catchments of the Sacramento-San Joaquin Bay-Delta. The model will account for water management practices, land use, pesticide use rates, and cumulative pesticide stress. Additionally, this work will produce a web-based tool to simulate current and future risks based on the ranking of primary sources of pesticide contribution. This work will provide a framework to predict risk from chemical stressors. Specific objectives are: (1) enhanced pro-active chemical risk assessment, (2) creation of a tool which enables science-based chemical use decisions, (3) improved risk screening for vulnerable areas, and (4) identification of adverse effects of current and future chemical use strategies.
    Science topics Herbicides
    Updated April 29, 2022
  • Title

    Harmonizing pesticide risk management of the Bay Delta watershed

    Lead University of California - Santa Barbara [UCSB]
    Description Objective One: Employ high-resolution irrigation data to predict pesticide risks in the Bay Delta Watershed (BDW). This effort will enable more accurate prediction of health hazards given irrigation is a key driver of pesticide transport to surface and ground water. The effects of irrigation methods to pesticide transport vary significantly in their contribution of pesticides to runoff/leachate due to effects on pesticide build-up/wash-off and soil moisture conditions antecedent to precipitation. Objective Two: Provide harmonized species indicators of pesticide toxic burden releases for the Bay Delta which consider diverse resident taxa and human health. California benefits from a plethora of academic researchers, environmental advocacy groups, municipalities, and government groups working to protect the environment. Due to the complexities of this work, efforts often focus on a particular taxa or environmental compartment. This introduces a significant challenge in evaluating the pros and cons of any particular pesticide use. Currently, 79 of the 208 watersheds near the Delta which receive agricultural pesticide applications have increasing pesticide toxic burdens to aquatic taxa. Enabling evaluation of chemical alternatives which reduce toxic burdens across taxa is important to restoring ecosystem health. Objective Three. Quantify the variability of pesticide degradation and the significance to pesticide risk in the BDW. The degree to which pesticides remain in the soils of the BDW increases their probability for accumulation, transport, and nontarget affects. Degradation is highly variable in soils; an investigation of 10 pesticides in 8 soil types under equivalent conditions demonstrated a mean difference of 540% in the minimum and maximum rate of degradation for pesticides evaluated. Yet, researchers and regulators often only employ the median observed rate of degradation which may under predict risks to waterbodies of the BDW.
    Science topics Pesticides
    Updated November 30, 2022