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Decontamination procedures were followed before and during the well construction operation. All casing and well screen was steam cleaned before its installation into the borehole. Care was taken not to introduce contamination into the wells. Using a surveying rod and transit, the top of all three well casings were measured in relation to a hypothetical benchmark of 100 feet. Actual surface elevation at this location is 5 to 10 feet above sea level. Distances between each well were measured using a steel engineer's tape. Distance to ground water for each piezometer was measured using a Solonist water sounding device. See Table 1 for specific groundwater gradients and flow directions. Groundwater flow directions and hydraulic gradients were measured approximately 1.5 hours after a high and low tide cycle, and at a low tide phase. Groundwater flow direction and hydraulic gradients were also measured on two other occasions but no tide data was available to compare these with. Groundwater flow direction appears to be highly variable,which may or may not be due to tidal forces. Seasonal rainfall and groundwater recharge or discharge from a nearby slough (see Figure 2) could also affect groundwater flow directions. TABLE 1 Groundwater Flow H draulic Date Time DirectioC[radient Tide 12/19/88 1630 N10W 2.28x10EE-03 'high 12/19/88 t 1040 N20E .016 `low 1/6/89 1145 N37W 2.78x10EE-03 --- 1/9/89 1230 N25W 3.49x10EE-03 low 2/3/89 1450 S68W 6.41x10EE-03 --- t water measurements were taken before wells were developed. --- tide data not avaiable measurements taken 1.5 hours after tide Note: Tide data was compared with that reported at the port of Stockton, the nearest tidal station to Gold Bond, and as listed in the Stockton Record newspaper. Initial groundwater samples were taken from the three piezometers on February 2, 1989. The wells were more thoroughly developed using an Isco bladder pump and an air compressor. From 16 to 25 well volumes of water were purged from the piezometers. Electric conductivity, pH, and temperature were measured during the purging. See Appendix C for specifics on the purged groundwater. No product or odor was apparent in the purged water. Samples were collected from each piezometer using the Isco bladder pump. Samples were collected into one liter amber bottles, labeled, logged on a sample management/chain-of-custody sheet,placed in a ice chest on ice, and cooled to 4 degrees Celsius. The samples were then shipped to AEMC's EPA certified laboratory for analyses. The samples were analyzed for TPH (total petroleum hydrocarbons) and PNA's (polynuclear aromatic hydrocarbons). See Appendix D for sampling protocol.