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Overhead/Lodi Door*. -2- 17 August 1987 <br /> At MW-4 I observed the measurement to be 43 feet on the cable, plus <br /> 2 . 1 inches on the scale. I asked Steve Raugust what he had <br /> measured. He replied that the depth to water was 43 . 21 feet (as <br /> opposed to 43 feet, 2 . 1 inches) . I noted the error, but did not <br /> point it out at that time. When MW-3 was measured the same error <br /> arose. The depth to water was read as 44 . 65 feet when it was <br /> actually 44 feet, 6. 5 inches. At this time I pointed out the error <br /> in reading the scale, and the previous measurements were changed. <br /> Errors of this magnitude are significant, considering the gentle <br /> gradient in the area. The possibility that this error may have <br /> occurred and gone unnoticed in the past casts doubt on the accuracy <br /> of water level measurements made by JHK to date. <br /> Depth to water after pumping was not measured in MW-4 . This <br /> measurement has been reported in previous monthly monitoring <br /> reports.. <br /> Water Sampling <br /> At MW-4 approximately 18 gallons were purged prior to sampling. <br /> This is more than 5 well volumes according to JHK calculations. <br /> This volume was measured by pumping into a five-gallon bucket. <br /> Previous monthly ground water monitoring reports, however, have <br /> reported the purge volume to the nearest 0. 01 gallon. Due to <br /> problems with pH meter calibration, only EC and temperature were <br /> monitored during the purge period. Discharge from the well was <br /> visibly free of solids. Decontamination of all sampling equipment <br /> was thorough. <br /> I obtained two samples of ground water from MW-4 in 500 ml bottles <br /> fixed with nitric acid, one unfiltered and one filtered with a 0. 45 <br /> micron in--line filter. JHK obtained samples for analysis of metal <br /> concentrations and standard minerals. <br /> Sampling of MW-4 took nearly three hours. Purging of MW-3 began at <br /> approximately 1330. After purging five gallons, the compressor ran <br /> out of gas and no extra fuel was on hand. I left at 1350 without <br /> collecting samples from MW-3 . <br /> INSPECTION SUMMARY <br /> Sampling protocol was thorough from the standpoint of minimizing <br /> contamination. Erroneous measurements of depth to water in wells <br /> were made. If such errors were made in previous months, <br /> calculations of ground water gradients based on these data may be <br /> seriously in error. <br /> ohn K.�Woodling, Eng. Geologist <br />