WORK PLANS - Laserfiche WebLink

Home Browse Search

APPENDIX A GROUNDWATER SAMPLING AND ANALYSIS PLAN The sampling and analysis procedures for the Cherokee Freight Lines (CFL) groundwater quality monitoring program are contained herein. The procedures provided will ensure consistent and reproducible sampling methods, proper application of analytical methods, and accurate and precise analytical results. A. GROUNDWATER SAMPLE COLLECTION Groundwater sample collection procedures include equipment cleaning, water level and total well depth measurements, and well purging and sampling. Groundwater samples will be collected quarterly from the CFL monitoring wells. 1. Equipment Cleaning Equipment that will be used to sample groundwater will be disassembled and cleaned with detergent water and then rinsed with deionized water prior to sampling. During field sampling, equipment surfaces that are placed in the well or come into contact with groundwater will be cleaned with deionized water before the next well is purged or sampled. 2. Water Level and Total Well Depth Measurements Before purging and sampling, the depth to water and total well depth will be measured using an electronic water level sounder. The electric sounder is a transistorized instrument that uses a reel-mounted coaxial cable that connects the control panel to the sensor. Cable markings are stamped at 0.01-foot intervals. The water level will be measured by lowering the sensor into the monitoring well. A low-current circuit is completed when the sensor contacts the water. The current is amplified and fed into an indicator light and audible buzzer, signaling when water has been contacted. A sensitivity control compensates for highly saline or conductive water. The electric sounder will be decontaminated by rinsing with deionized water after each use. Groundwater level measurements will be recorded to the nearest 0.01 foot on a field data sheet. Groundwater levels will be collected from all monitoring wells at the site on the same day. The groundwater elevation at each monitoring well will be calculated by subtracting the measured depth to water from the surveyed elevation of the top of the well casing. Total well depth will then be measured by lowering the sensor to the bottom of the well. Total well depth, used to calculate purge volumes and to determine whether the well screen was partially obstructed by silt, will be recorded to the nearest 0.01 foot on a field data sheet. Project Workplan A-1 SA1433 July 30,2004 nAsa01433\gwmwiwp\workp1an.doc