WATER-TABLE CORRECTION FACTORS APPLIED TO GASOLINE CONTAMINATION

The application of correction factors to measured ground-water elevati ons is an important step in the process of characterizing sites contam inated by petroleum products such as gasoline. The water-table configu ration exerts a significant control on the migration of free product ( e.g., gasoline) and dissolved hydrocarbon constituents. An accurate re presentation of this configuration cannot be made on the basis of meas urements obtained from monitoring wells containing free product, unles s correction factors are applied. By applying correction factors, the effect of the overlying product on the apparent water-table configurat ion is removed, and the water table can be analyzed at its ambient (un disturbed) level. A case history is presented where corrected water-ta ble elevations and elevations measured at wells unaffected by free pro duct are combined as control points. The use of the combined data faci litates a more accurate assessment of the shape of the water table, wh ich leads to better conclusions regarding the source(s) of contaminati on, the extent of free-product accumulation, and optimal areas for foc using remediation efforts.