Transport and fate of sediment and associated contaminants in SF Bay. Mike Connor & John Oram 2007 LTMS Science Workshop

Transcription

1 Transport and fate of sediment and associated contaminants in SF Bay Mike Connor & John Oram 2007 LTMS Science Workshop

2 Major Points Bay Still Responding to 1800 s mgmt Transport Has Spread Contamination Widely Future Bay Depends on Mixing of Legacy Contaminants Bay Sediment Ecosystem in Major Overhaul Overall Bay Status Assessment Will Change with Sediment Quality Objectives

3 Sediment yield Hydraulic Mining Dominates the Bay Sediment Budget Practiced from , then outlawed. >100 million m3 of sediment washed into Central Valley. Main bed sediment pulse passed Sacramento ~1950. Channel and floodplain deposits remain. still moving thru system. Expected response Expected response time

4 Delta Sediment Inflow Gilbert, Porterfield, Krone, OBA, McKee et al.

5 Sediment Accounting 101

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8 Point San Pablo SSC and Mercury

9 Sediment dynamics explain spatial patterns in contaminant concentrations.

10 Estuarine Turbidity Maxima Petaluma River Sonoma Creek Benicia surface Benicia bottom Mallard Is surface Garnet Sill bottom J F M A M J J A S O N D Tidal max mg/l > <100

11 Legacy Ratio: Reservoir/Loadings

12 Contaminant Distribution Depends on Sources & Transport Processes

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15 Model Overview

16 Model Overview

17 Forecast Setup : Sedimentation

18 Hindcast Results After Calibration Error Bars: EMAP & RMP = Standard Deviation of Samples Model = Aggregate Uncertainty

19 Hindcast Results After Calibration

20 Base Forecast : Recovery Due to Natural Attenuation Net Erosional Net Depositional

21 Base Forecast Sensitivity to PCB Profile Sensitivity

22 Base Forecast Sensitivity to PCB Profile Sensitivity

23 Base Forecast Sensitivity to PCB Profile Sensitivity

24 Base Forecast Sensitivity to PCB Profile Sensitivity

25 Loading Scenarios : Local Tributary Loads

26 Loading Scenarios : No External Loads

27 Changing Bay Sediment Ecosystem Sediment Supply Invasive Species Light Penetration Bathymetry Erosional Processes Biological Structure

28 Chlorophyll a (mg/m 3 ) Autumn-winter blooms appear in 1999 Interquartile Ranges Show Overall Trends of Increasing Chla during autumn-winter Chlorophyll a (mg/m 3 )

29 Present (~2000) Future (~2030) 13,000 acres restored 35,000 more in the works

30 Few Eelgrass Beds Remaining in Bay

31 Current Shoreline 1 m Sea Level Rise Area Future Shoreline?

32 Toxicity Categories Nontoxic: Response not substantially different from that expected in sediments that are uncontaminated and have optimum characteristics for the test species (e.g., control sediments) Low toxicity: A response that is of relatively low magnitude; the response may not be greater than test variability Moderate toxicity: High confidence that a statistically significant toxic effect is present High toxicity: High confidence that a toxic effect is present and the magnitude of response includes the strongest effects observed for the test

33 Amphipod Species Recommendations Recommended Eohaustorius estuarius Leptocheirus plumulosus Not recommended Ampelisca abdita Low sensitivity Low test success rate

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35 Benthic Effects

36 Chemical Exposure

37 Multiple Level of Effects (MLOE)

38 Major Points Bay Still Responding to 1800 s mgmt Transport Has Spread Contamination Widely Future Bay Depends on Mixing of Legacy Contaminants Bay Sediment Ecosystem in Major Overhaul Overall Bay Status Assessment Will Change with Sediment Quality Objectives