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I <br /> City of Stockton A68104 01A <br /> 16 October 25, 1995 Page A-4 <br /> The development of each groundwater monitoring well continues until a minimum of five <br /> well casing volumes of water have been removed, and the displaced water is relatively clear, <br /> free of sediment, and the values of Ph, temperature, and specific electrical conductance <br /> (EC) have stabilized Well development data is recorded on the Well Development Log <br /> Purged water is containerized in Department of Transportation-approved drums, and stored <br /> on site in an area inaccessible to the general public The purged water is typically <br /> characterized either by sampling it, or on the basis of the groundwater sample analytical <br /> results Twining can recommend an appropriate method for disposition of the purged water <br /> Disposal will be the responsibility of the client <br /> A-4 Standard Overating Procedures for Groundwater Monitoring Well Sam lin <br /> Groundwater sampling is performed a minimum of 24 hours following development, or when <br /> the post-development water level in the well has returned to the static level Before purging <br /> and sampling is performed, the depth to water and the total well depth is measured If <br /> floating hydrocarbons are suspected, a bottom-filling clear bailer or hydrocarbon-detecting <br /> paste bailer may be used to record floating hydrocarbon thickness Depth to water is <br /> measured with an electric sounder, according to Twining's "Standard Operating Procedures <br /> for Measuring Depths to Water and Calculating Groundwater Elevations" <br /> Prior to sampling a monitoring well, a minimum of 3 well casing volumes is purged using <br /> a clean, stainless steel submersible pump or a disposable bailer equipped with a length of <br /> new rope Disposable bailers and rope lengths will be used once, and discarded After 3 <br /> casing volumes of water have been removed from the well, purging continues until measured <br /> field parameters (Ph, specific electrical conductivity, and temperature) have stabilized <br /> Purging data is recorded on the Well Sampling log <br />