ARCHIVED REPORTS_XR0002448 - Laserfiche WebLink

Home Browse Search

HI Mr. Bill Vizza 30 November 1993 Page 5 polyethylene bailer. Purge water was placed in 55-gallon drums, labelled and stored on site. During purging, the groundwater field parameters of Ph, electrical conductivity and temperature were monitored. For quality control, the Ph meter and conductivity meter were calibrated at the beginning of the sampling day with commercially available standards. Purging was continued until field parameters had stabilized and a minimum of three well volumes of water were removed from the well After purging the well, samples were collected in containers obtained from and prepared by the analytical laboratory according to the requirements for the specific analysis. After each sample was collected, the bottles were immediately sealed and labelled. The groundwater samples from each of the wells was identified with a unique sample number, the project number, date and time collected, sample location and sampler's name. After labelling, each sample bottle was placed in a chilled cooler and delivered under Chain of Custody documentation to Matrix Environmental Laboratories in Rancho Cordova for analyses. Field information gathered during collection of groundwater samples, chain of • custody sheets and laboratory data sheets are attached with this report. RESULTS OF FIELD INVESTIGATION AND LABORATORY ANALYSES Field Observations Shallow soil encountered consistdd of clay to silty clay which graded with depth into a sand aquifer. The shallow saturated interval was penetrated at depths ranging between 6 to 9 feet below ground surface where sand was predominately present. Groundwater level were measured on two occasions following completion of well development activities. The first set of water level measurements were obtained on 19 October 1993 during groundwater sample collection activities The second set of measurements were collected on 27 October 1993 when well head and ground surface elevations were surveyed using an temporary bench mark. Water level measurements and survey results are presented in Table 1. Calculation of groundwater flow direction and flow gradient made using each of the two data sets revealed significantly different flow characteristics Calculations based on 19 October 1993 measurements revealed the groundwater flow direction to be towards the southeast at a gradient of 0 0479 foot/foot. Calculations based on the 27 October 1993 measurements revealed the groundwater flow direction to be towards the northeast at a • gradient of 0.0096 foot/foot. Inspection of the magnitude of the flow gradient and the difference in measured groundwater levels indicates that the observed differences are