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method (Billings 1972 ). When using the three-point method with five known elevations, 10 independent downgradient solutions are Possible. Where the directions of these solutions are con- flicting, only the three-point solutions which utilized the largest triangles are shown. Use of the most widely separated wells (the largest triangles) will theoretically maximize the reproducibility of the resulting downgradient direction solution by eliminating the effects of s local irregularities in the downgradient direction. p. Figures C--1 through C-9 demonstrate that through the last two years the downgradient direction has been generally toward the northeast, and the gradient has been very shallow (less than 0.002 as. .-,...Easured from MW1 to MW2 ) . Figure C-3 (August 19$8 ) and Figure C-7 (July 1989) show that the gradient during these periods was partly toward the east-southeast. Figures C-5 and C-6 show that the relief on. the groundwater surface was so small t during the spring of 1989 that a downgradient direction could not ( be preei ,ely .determined. . Since the groundwater elevation data show a consistent, very. low gradient across the site (Table 2) and since no cuttingsof unusually impermeable lithology are reported .on the drill logs,, _ there is no evidence that MW2 is. campleted .in .a different aquifer than that penetrated by the other wells on the. site These gradient.calculations indicate that well MW2 is located downgradient from .well .MW3: ' 3. RW CB te con .. . Q nds .that although the results of quarterly groundwater' sampling have shown a. generaI decrease in r hydrocarbon .contamination 'levels in the groundwater with time, ."it is unlikely that the high levels of hydrocarbon. r-- contamination reported in groundwater during previous investigations has been significantly degraded. " RWQCB :e35/71050/2-90/tX 8