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i <br /> Attachment 3 <br /> GROUNDWATER MONITORING, SAMPLING, <br /> AND SAMPLE MANAGEMENT PROCEDURES <br /> 1. Notifications <br /> Prior to performing any held work, the client, regulatory agency, and property owner/manager <br /> with jurisdiction over the subject site are notified Notifications are made a minimum of 48 hours <br /> prior to sampling, or as required by the client or regulator <br /> 2. Water Level Measurements <br /> Prior to performing purge or no-purge sampling, water level measurements are collected <br /> according to the following procedures <br /> • All wells are checked for phase-separated hydrocarbons with an acrylic bailer or <br /> oil/water interface meter <br /> • To avoid cross contamination, water levels are measured starting with the <br /> historically "cleanest"wells and proceeding to the historically "dirtiest " <br /> • Water levels within each well are measured to an accuracy of ±0 01 foot using an <br /> electric measuring device and are referenced to the surveyed datum (well cover or <br /> . top of casing) When measunng to top of casing, measurements are made to the <br /> notched (or otherwise marked) point on casing If no marking is visible, the <br /> measurement is made to the northern side of the casing <br /> • If possible, all wells are gauged within a short time interval on the same day to <br /> obtain accurate measurements of the potentiometric surface <br /> • All measurements are reproduced to assure validity, and measuring equipment is <br /> decontaminated between wells <br /> 3. Phase Separated Hydrocarbon <br /> If phase-separated hydrocarbon (PSH) is encountered, its thickness in the well and the depth to <br /> the interface between the PSH and the water in the well are measured using one or both of the <br /> following methods <br /> • an electronic oil-water)Interface meter is used to measure the depths to the top of <br /> the PSH and to the top of the water, and/or <br /> • an electronic water level meter is used to measure the depth to the top of the water <br /> and a clear bailer is used to measure the PSH thickness <br /> The potentiometeric surface elevation is calculated as <br /> TOC - DTW + 0 74PT <br /> Main\D\Environmentar�ParmarTexaco\Workplan�042003 wpd 1 <br />