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• • • GROUNDWATER SAMPLING AND ANALYSIS PLAN • • The sampling and analysis procedures for the 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 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 distilled 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 distilled 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 distilled 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. • • 3. Well Purging • Monitoring wells will be purged prior to sampling to remove stagnant water from the • well casing and filter pack using a bailer, centrifugal pump, or low-flow submersible • • Riverbank WWTP Workplan Nolte Associates,Inc. • March 2005 A-1 \\SasO\project\SAI 542\mon_we1l\new\gwmwiwp\wp.doc •