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.. Work Plan far Refined Plume Definition and Management of Floating Product-7500 W 11th St., Tracy, CA. Page 38 Monitoring Well MW-7 is 0.3, given the measured thickness of 0.58 ft., then the total volume of floating product in the boring on November 8, 2003, amounted to 0.07 W (i.e., 0.52 gal.), which is the sum of the LNAPL in the casing itself plus that in the pores of the filter in the annular space between the casing and the wall of the 8-in. diameter boring. Since no measurable quantity of LNAPL flowed into the well over the 7-day period between ._ November 15 and November 22, itis clear that the 0.58 ft. of free product found on November 8, 2003 had accumulated in the well at an extremely slow rate. Thus, by corollary, it is reasonable to estimate that only a de minimus volume of LNAPL entered the well over .,. the 14-day period between November 8th and 22nd, when groundwater in the well was found to be essentially free of LNAPL. This indicates that the total volume of floating product removed from the well by the three purgings that occurred over that period had a total •• volume close to that calculated above (i.e., 0.52 gal.). That estimate is compatible with the field reports made by SJC staff, which indicate that on each of the first two purgings that LNAPL having a total volume of very much less than 1 gallon was recovered from the well *- and none was recovered at the time of the third purging. Even a one month delay from the third to fourth purging yielded no measurable thickness of floating product and less than one ounce of recovered LNAPL. The tiny volume of LNAPL that it was possible to recover from Monitoring Well MW-7 over period from November 8 to December 21, 2003 (See Table 3) might, on first inspection, be difficult to explain. This difficulty might be generated by comparing the facts about the plume of floating product that are currently known and the small volume of LNAPL recovered from that well in the cited period. Without needing to know the precise magnitude of the volume of floating product that might actually present in the subsurface (see Section 5.2.4), it is clear that the LNAPL was originally released on the other side of West Eleventh Street at a distance of some 200 ft. up gradient from MW-7 (see Section 5.2.3) has reached that location and, based on the measurements of thickness of LNAPL in that well has an estimated actual thickness of some 0.33 ft. in the surrounding formations that the volume of r floating product present in the subsurface must be orders of magnitude greater than the —fractional -gallonage of product purged from the well before no measurable thickness of LNAPL cold e measured in it. However, when the soil mass properties, drilling effects and scalar effects related to the hydraulics of flow to a small-diameter well that are discussed in 9.3 below are considered, the observed behavior of the LNAPL in the well can be explained. That evaluation illustrates the significant difficulties that are encountered when removal of floating product from a wide-spread plume is attempted by skimming product from the water table in small-diameter wells. As was discussed in Section 5.2.3, SJC estimates that the width of the migrating plume of floating product beneath the north side of West Eleventh Street is on the order of 100 ft. in width and that the total volume of recoverable LNAPL in the subsurface is on the order of several thousand gallons. Under those circumstances, it is clear that while the purging of LNAPL from MW-7 has temporarily removed free product from its immediate vicinity, the great mass of that material continues to move in a wide swath northward from West Eleventh Street. It is probable that free product may slowly re-accumulate in the casing of Monitoring SJC