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Stote Req. • from the monitoring program because the site monitors runoff from undis- turbed land and the doto collected have no relevance to the mine. Sites SW-S2-I through SW-S2-6 are monitored monthly for instantaneous flow and field pH, conductivity, and temperature. The exception to this program is that sites SW-S2-5 and SW-S2-6 are not monitored during the winter months of December, January, and February as approved by the CMLR after the 1962 annual hydrology report was reviewed. Crest stage gages at each of the sites record peak flow stage heights which are related to volumetric flow rates via rating curves developed from channel surveys and the Manning equation. These rating curves are presented in Addendum 7-IOA to Appendix 7-10 of this permit revision. Site NPDES 002, 003, and 004 are monitored weekly for the parameters stipulated in NPDES Permit No. CO-0000221: flow, total suspended solids, total iron, salinity, pH, oil and grease, and floating solids. Flow at sites NPDES 002 and 003 is monitored continuously via H-flumes and Stevens • Type F water level recorders. Flow at NPDES 004 is monitored continuously via a Parshall flume and a Stevens Type F water level recorder. ' A11 the surface water monitoring sites except SW-S2-2 and SW-S2-6 are sampled tri-annually for the "short" parameter list presented in Table 7-10-9. Sites SW-S2-2 and SW-52-6 are downstream of all mining related disturbances and are consequently sampled tri-annually for the "long" para- meter list presented in Table 7-10-10 which includes the trace elements aluminum, arsenic, boron, cadmium, copper, lead, mercury, molybdenum, phosphorous, selenium, silicon, and zinc. The different parameter lists were approved by the CMLR staff on April 4, 1984 following a review of the historic water quality data. The first iri-annual sample in each year is collected prior to peak runoff, the second sample is collected after peak runoff, and the third sample is collected during baseflow conditions. Samples are analyzed as per U.S. EPA (1979). . All surface water monitoring sites will be properly maintained by qualified personnel. Following reclamation bond release, all monitoring equipment will be removed and the sites will be regraded and vegetated. 7-10-23 Revised September 28, 1984 ~,