Laserfiche WebLink
Mr. Travis Marshall <br />September 23, 2008 <br />Page 2 of 3 <br />• Prior to installing the pumping equipment, measure and record the initial static <br />water-level in the well using a pressure transducer or water-level indicator. <br />• Slowly lower the decontaminated pumping assembly into the well taking care to <br />minimize disturbance to the water column. <br />• Set the pump intake at the specific depth determined in advance (the midpoint of the <br />open interval unless geophysical logs or other information indicate otherwise). <br />• Continue to monitor and record the water level in the well to ensure that the level <br />has stabilized to the pre-pump installation level before engaging the pump to purge <br />and sample the well. <br />• Continue to monitor the water level in the well during purging and sampling and <br />adjust the purging rate as necessary so drawdown in the well is minimized and does <br />not increase over time. <br />3. For micro purge method, at what depth below the static water level will the sampling pump be <br />engaged? <br />AMSO Response: <br />As discussed in our response to Issue No. 2 above, the pump intake will be placed near the <br />midpoint of the open interval in the well. Depending on the type of pump used, the pump <br />itself will either be placed at the intake depth (HydroboosterTM or equivalent) or approximately <br />50 feet below static water level with intake tubing extending to the open interval (bladder-type <br />pump). <br />4. For micro-purging, what changes in water qualityparameters are expected during the 5-10 <br />minute monitoring intervals and how will they affect the method and timing of sample <br />collection? <br />AMSO Response: <br />The list of water-quality-indicator parameters presented in Section 3.3.2 (Groundwater <br />Sampling) of the AMSP Sampling and Analysis Plan for Surface-Water and Groundwater <br />Monitoring has been expanded to include turbidity. The list of indicator parameters includes <br />pH, temperature, specific conductance, turbidity, oxidation-reduction potential, and dissolved <br />oxygen. The specific intervals for parameter measurement will depend on the volume of water <br />within the tubing (including pump and flow-through cell volumes), pumping rate, and <br />drawdown A minimum of one tubing volume (including pump and flow-through cell <br />volumes) will be purged from the well prior to recording water-quality-indicator parameters. <br />The parameters will then be recorded in accordance with the established parameter <br />measurement intervals. Groundwater samples will be collected after three successive reading <br />of the parameters have stabilized.