Guadalupe River Watershed Model, Year 2

Authors: John Oram, Michelle Lent, Lester McKee (SFEI)

High levels of PCBs and mercury have been detected in the Guadalupe River. The RWQCB, SFEI and other agencies have developed an extensive database of concentrations of contaminants in water, sediment, and fish tissues in the Guadalupe River watershed. In part based on these data, the Guadalupe River Watershed TMDL identifies fish mercury targets, bed and suspended sediment targets for runoff from mining areas, and load allocations from urban areas. The Bay Hg TMDL calls for Guadalupe River watershed load reductions of 98% and the Bay PCB TMDL calls for load reductions of >95% for urban areas. In response, managers in the Guadalupe River have already started implementing management actions to mitigate contaminant effects including experimenting with aeration in the reservoirs to reduce mercury methylation and removal of contaminated sediment from drainage lines.

The aim of this project is to begin the development of a numeric model to assist in estimating mass loads of mercury and PCBs; to extrapolate the data to determine long-term average loads for the period of extensive rainfall data collection (1973-present); and to determine the proportional sources in the watershed and refine the assumptions of the Guadalupe River Hg TMDL. Ultimately the model will be used to assess the effects of best management practices and impacts of wetland restoration (e.g., effects of South Bay Salt Pond restoration).

This multi-year project began in 2008. In 2008, a model was developed based on land use maps, precipitation, topography, and runoff. In 2009 information on sediment and contaminants will be incorporated into the model (this was not accomplished in 2008). In year two, continued testing of the model will occur and the model will be updated to include sediment transport. A draft report of the model will be prepared and distributed for review.

Small Tributaries Loading Study, Watershed 2 Zone 4 Line A

Author: Lester McKee and RMP staff (SFEI)

The Small Tributary Loading Strategy team is currently developing a list of priority questions and monitoring needs. It is anticipated that a small tributary loading study will be developed upon completion of the strategy.

Continued Development of Mercury Toxicity Thresholds for Egg Hatchability in Forster’s Terns

Authors: Collin Eagles-Smith and Josh Ackerman (USGS)

The goal of this project is to develop egg thresholds for mercury. The USGS has developed a method in which a small amount of the individual egg albumen is sampled for mercury using micro-techniques. The amount of albumen is so small that the egg remains viable. The egg is then tracked to determine the success of the hatch and chick. USGS began this technique in 2007 and will build upon the information collected to date. USGS will donate in-kind services to complete this project

Impacts of PAH-contaminated Sediment on Early Life History Stages of Benthic Fish, Year 2

Author: John Incardona (NOAA)

This is the second year of funding for a two-year project evaluating the effects of PAH-contaminated sediments on the development of juvenile flatfish. The impacts of pyrogenic PAHs (like those detected in San Francisco Bay) on juvenile flatfish development are largely unknown. In the first year, the effects of pyrogenic (...