Introduction of Version 2.0b Significant changes to sediment model –Box volumes are no longer static. –Net sedimentation is constrained by box geometry. –Tributary loads do not include bed loads, only suspended fraction. –Tributary loads distributed representatively between Bay segments –Calibrated to net sedimentation for 4 South Bay subregions reported by Jaffe et al. –Improved boundary conditions at Delta and Lower South Bay. (improved mass conservation)

Introduction of Version 2.0b Implications for PCB model: –Improved mass conservation (99.98% daily conservation) –Improved accounting of sediment-water exchange. –Constrained erosion/deposition improves forecast.

Future Plans (v2.0) Address comments from v1.0 draft report and incorporate changes into v2.0 (in progress) Calibration and Validation –Sediment sampling to improve estimates of PCB inventory and historic loads –Tracer experiments to quantify flushing, compare with obs. Uncertainty and Sensitivity Analysis – with TetraTech –Monte Carlo type UA –More rigorous SA v2.0 draft and final reports – (Draft = September 2005)