Laserfiche WebLink
SOP-009 Standard Operating Procedure Low-Flow Groundwater Quality and Sample Collection <br />Page 3 of 9 Revision No. 1 April 2019 <br /> <br />Sharpe Army Depot <br />accurate measurement can be determined. Adjust well sounder sensitivity as necessary to get a good reading. Obtain the reading from the established mark on the well casing and measure to the nearest 0.01 foot. If no established mark is present, the north side of the top of casing should be used. Record water level on the appropriate field forms. Once the water level has been recorded, slowly lower the probe to the bottom of the well. Record the total depth on the appropriate field forms. <br />After a water level measurement is collected at a groundwater monitoring well, decontaminate the measuring tape and reel. After decontamination is completed, properly secure the sounder in the sampling vehicle before moving on to the next location. <br />4.4 Equipment Setup <br />Lie out and connect electric cords to vehicle battery from the pump. Lie out and connect pump discharge tubing from pump to flow-through-cell and from flow-through-cell to purge water storage tank. Keep tubing and equipment in shade whenever possible. <br />Check the well construction details and depth to water measurement. Lower the pump (or tubing) to the bottom of the well and then withdrawing half of the screen length, plus the length of any sump sections at the bottom of the well. If the well is heavily silted (based on well measurements), lower the pump (or tubing) a measured distance to place it at mid-screen without touching the bottom of the well. Make sure the pump is decontaminated (SOP-003) accordingly with deionized water and soap between locations or remove wetted materials and replace with new components in between wells. New or dedicated tubing should be securely attached to the pump head and decontaminated or replaced between locations. Secure the pump electrical line and discharge tubing to the top of the well in a manner to avoid kinking once the desired depth has been reached. Record depth to water and depth to pump in the field log. <br />Attach the end of the discharge tubing to the flow through cell that has been setup with the calibrated water quality multi-meter. Attach the discharge of the flow through cell to a bucket for collecting purge water. <br />Attach the end of the pump’s electrical connector to the controller and connect the controller to the battery. The pump should start running once the controller is on and hooked up but it may take a few minutes for water to come up to the surface. Adjust the flow accordingly if no water is being produced. Allow the flow through cell to fill before taking the first reading. <br />Measure the flow rate with a graduated cylinder and timing devise and record the flow as milliliters per minute (mL/min). Also record the cumulative volume purged as liters (L) and the water quality parameters temperature, pH, conductivity, dissolved oxygen, oxidation reduction potential, and turbidity. <br />Low-flow dedicated pump purging and sampling will consist of low flow 12 volt Geosquirt, or equivalent, low flow type pump to purge wells. This pump type is meant to pull water from approximately 120 feet below ground surface or shallower. If the well is too deep to pump adequately, lift the pump in the water column and record the pump depth on the field log.