ARCHIVED REPORTS_2016_1 - Laserfiche WebLink

Home Browse Search

n Water Quality Monitoring Report Forward Landfill potential (ORP), turbidity, temperature, specific conductance, and pH and recorded on well data sheets. The groundwater monitoring wells and leachate monitoring points were sampled in accordance with the sampling and analysis plan detailed in Appendix D. The well data sheets, raw laboratory data, certificates of analyses, and chain -of -custody records related to the sampling program are included in Appendix E. Field and laboratory analyses are summarized in Tables 2-2 through 2-8 and cumulative tabulated data for all monitoring points and constituents for groundwater, unsaturated zone, leachate, and surface water are presented in Appendix E. 2.1.2 QA/QC Results The quality assurance/quality control (QA/QC) program completed for the first quarter 2016 water quality monitoring event included analyses of one trip blank, one field blank, laboratory method blanks, and one duplicate sample (MW -18). The field and trip blanks were analyzed for VOCs by EPA Method 8260, and the method blanks were analyzed for all of the analytes included in the monitoring program. The results of the QA/QC program indicate that no VOCs and no inorganic constituents were detected in any of the QA/QC blanks during the first quarter 2016 monitoring period. The results of the duplicate sample collected from well MW -18 yielded good correlation with a relative percent difference (RPD) less than five percent. Review of the sampling dates and laboratory analytical certificates indicates that all laboratory analyses were completed within required holding times. Based on the results of the laboratory QA/QC analyses, it is concluded that the laboratory data generated for the first quarter 2016 monitoring period are acceptable and the water quality samples collected from the Forward Unit appear to be representative of water quality at the site. 2.1.3 Groundwater Elevations and Contours Prior to purging and sampling, each well was sounded for water depth using a weighted electronic sounder to an accuracy of 0.01 foot, and the static water level was recorded on a Well Data Sheet (Appendix E). The groundwater elevations were calculated for each well by subtracting the depth -to -water measurement from the top -of -casing reference elevation. The current groundwater elevation data for the Forward Unit is summarized in Table 2-3. The groundwater elevation data obtained on February 17, 2016, were used to generate the groundwater elevation contour map shown on Figure 2-1 for the first quarter 2016 monitoring period, which indicates that groundwater beneath the southern and central portions of the Forward Unit flows to the south at a hydraulic gradient of 0.001 ft/ft; while groundwater beneath the northwestern portion of the Forward Unit flows to the northeast at a hydraulic gradient of 0.002 ft/ft. To calculate the approximate linear groundwater flow velocity for the Forward Unit, conservative assumptions were used, including a hydraulic conductivity of 875 gallons M:\ 2016.0007\FA 1Q16.docx 5