Laserfiche WebLink
First groundwater has stabilized in MW 1 at approximately 65 feet below grade Natural <br /> Groundwater gradient direction would be expected to be north-northwesterly, towards the <br /> Calaveras River A long history of groundwater use in the Stockton area, however, has resulted <br /> ' in significant local variations in gradient Groundwater gradient direction at nearby sites ranges <br /> from northeasterly to southerly <br /> ' OBJECTIVES AND SCOPE OF WORK PROPOSED <br /> The objectives of this investigation are to <br /> • To attempt to determine the shallow groundwater direction and hydraulic gradient to <br /> ' enable the prediction of the movement of contaminant in the first groundwater beneath <br /> the site <br /> ' • Further define the magnitude n <br /> g tude a d lateral extent of petroleum hydrocarbon impact of the <br /> first groundwater beneath the site <br /> ' To achieve the above objectives it will be necessary to install additional monitoring wells The <br /> following scope of work is proposed <br /> • Prior to selecting the locations of additional groundwater monitoring wells, we will <br /> monitor and survey monitoring well MW-1 and the irrigation well closest to the former <br /> tank pit (shown on Figure 2) <br /> • Determine the general direction of the hydraulic gradient of the upper-most aquifer at <br /> ' the site <br /> ' • Drill two soil borings in the estimated downgradient direction of the former tank <br /> locations Analyze selected soil samples collected from the borings for benzene, <br /> toluene, ethylbenzene and xylenes (BTEX) and total petroleum hydrocarbons as gasoline <br /> (TPHG) by EPA methods 8020 and modified 8015, respectively <br /> ' x-021492 LF 5 <br />