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drop in the stream channel. High flows are computed using measurements of the stream <br />cross section and values of the stream velocities measured with a stream velocity meter or <br />a float to determine velocity. Float velocities are multiplied by a correction factor of <br />O.B. <br />NPDES discharge points have been equipped with flumes and continuous flow recorders. <br />Continuous flow is not monitored in the winter sSnce the flumes and float stilling wells <br />freeze up. Rating curves used for flume data reduction were derived by comparison of <br />stage heights with flow measurements obtained by the methods mentioned Sn the previous <br />paragraph. <br />Procedures used to collect ground water quality samples are dictated by individual well <br />site conditions such as casing diameter, depth to water, casing storage volume, rate of <br />recovery, and pumping capabi litles of sampling equipment. Alluvial and bedrock wells are <br />sampled by purging a minimum volume of water at a constant rate while concurrently <br />measuring field parameters (temperature, pH, and electrical conductivity) for stability, <br />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 <br />• device has been established for each monitoring well based on consideration of well site <br />conditions, field parameter measurements, and evaluation of water quality anal ytlcal <br />results. Table 7-108 presents the ground war et sampling procedures put into effect Sn <br />Auaus t, 1993. For procedures prior to that, see the remarks page that accompanies the <br />water qua'_ity data presented rn Appendix 7-2C. <br />Dev_ces ~s ed to sample all uvlal wells include either barleys c_ submersible pumps, and <br />-, =n er 6a,iers, suUme rs ible pumps, er pos:Tive drsp'_acement pumps are used to sample <br />bedrock wells. Ground water levels are measured with an electronic water level indicator. <br />water leeeis in some shallow alluvial wells ate measured drrectiy with a steel tape. <br />Flowing wells e:e measured with a pressure gage. Pressure readlnas (in psi) are <br />mu'_tiphed by :. 3i to obtain feet of head. Water level data pce_'ir.ed with a minus (-) <br />sign ine:cate that the water level is above ground level. <br />-. Y.Ydre_ogic Data <br />~~ inLrJdllcLlGn <br />Hydrologic data collected at the Seneca II Mine from 1981 to 1996 are presented and <br />discussed .n the fcllowing section. Host of the hydrologic data previously presented in <br />Appendices 7-2 and 7-4 have been completely replaced with new reports. <br />7-355 Revised 02/05/97 <br />