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cross section and values of the stream velocities measured with a current meter, or a float to determine <br />velocity. Float velocities are multiplied by a correction factor of 0.8 (Brakensiek et al., 1979 and Buchanan <br />and Sumers, 1968). <br />Sites YSSF2, YSSF3, WSSF3, YSAF4, and YSGF5 have been equipped with Parshall flumes and <br />continuous flow recorders. Continuous flow is not monitored in the winter since the flumes and float stilling <br />wells freeze up. Rating curves used for flume data reduction were derived by comparison of stage heights <br />with flow measurements obtained by the methods mentioned in the previous paragraph. <br />Procedures used to collect ground water quality samples are dictated by individual well site conditions such <br />as casing diameter, depth to water, casing storage volume, rate of recovery, and pumping capabilities of <br />sampling equipment. Alluvial and bedrock wells are sampled by purging a minimum volume of water at a <br />constant rate while concurrently measuring field parameters (temperature, pH, and electrical conductivity) <br />for stability, and then collecting the sample once the field parameters have stabilized and the minimum <br />volume of water has been purged. The minimum purge volume, purge rate, and sampling device has been <br />established for each monitoring well based on consideration of well site conditions, field parameter <br />measurements, and evaluation of water quality analytical results. Table 15-7, Ground Water Quality <br />. Monitoring Procedures, Yoast Mine, presents the ground water sampling procedures put into effect in <br />August, 1993. For procedures prior to that, see the remarks page that accompanies the water quality data <br />presented in Appendix 74, Ground Water Chemistry Data. <br />Devices used to sample alluvial wells include either bailers or submersible pumps, and either bailers, <br />submersible pumps, or positive displacement pumps are used to sample bedrock wells. Ground water <br />levels are measured with an electronic water level indicator. Water levels in some shallow alluvial wells are <br />measured directly with a steel tape. <br />Sampling protocol is reviewed and maintained in a systematic fashion that delivers reliable data. Peabody <br />will continue to implement improvements in sampling protocol to minimize errors affecting both field <br />chemistry measurements and sample collection. <br />C7 <br />20 Revised 2/99 <br />