1. Hampton Bays At least one UST release MTBE, TAME TBA degradation product Upper Glacial; Magothy Sensitive shallow saline surface water discharge IRM rate In-situ follow-up?

2. Critical Prediction Maximum MTBE concentration at Interim Remedial Measure well for number and sizing of Air Stripping Towers – Limited space Neighborhood - Location pre-determined

3. Hampton Bays Source Contamination first identified Shallow bay

4. Characterization Multi-level transects across plume Typically 8 to 12 nested sampling/wl points Oxygenates, BTEX, EAs No full single sampling event yet Typical representative sample: Volume: 100,000 c-ft (x porosity)* Area: 300 sq-ft (x porosity) Spacing: 40 ft * Long Island ‘Rule of Thumb: 50,000 to 100,000 c-ft

5. Model Domain Source Contamination Source Shallow bay – constant head

6. Plume Centerline

7. Anthropogenic Recharge

8. Gridded MTBE

9. Modeled Pathline - XY

10. Modeled Pathline - RZ

11. IRM Recovery Well Highest Concentration along IRM ~ 10,000 ug/L

12. IRM - Recovery Predicted from mass-flux: ~ 2,500 ug/L Predicted from model: ~ 2,500 ug/L Actual: ~ 6,300 ug/L Dilution only 1.5:1? OR Extra Mass?

13. New Well(s) Concentration 21,000

14. Current Work Examine maximum-concentrations that could exist in the plume centerline, consistent with measured data Postulate XYZ locations of several points in plume centerline Estimate values at points Krig points onto existing starting concentrations until best match

15. Salient Point Even at some of the most well characterized sites, there is detail that is not captured. A model calibrated to the data will always miss these details – but the possibilities can be investigated.