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embankment slopes. The principal spillway outlet has been a <br />sharp-crested 90° V-notch weir. The redesign of the principal <br />spillway will utilize a drop inlet spillway with a 6-inch barrel <br />diameter and a 12-inch riser diameter. In order to continue <br />monitoring flow continuously out of the pond a.s required by the <br />approved monitoring program (Appendix A), an appropriately sized <br />H-flume with a continuous recorder will be installed immediately <br />below the principal spillway outlet as soon as possible, weather <br />permitting, after the pond reconstruction work teas been completed, <br />which has been projected to be in the early spring of 1987. <br />4. Site SW-N2 <br />Site SW-N2 is located below mining on the lower reach of the <br />West Return Ditch immediately above its confluence with Tuttle <br />Drawn as shown on Er.hibit i. This site was monitored for flow and <br />quality three times in 1980; the monitoring dat:a are presented in <br />Appendix B. Monitoring at this site was abandoned in the fall of- <br />1980 because upstream monitoring at NPDES 001 and downstream <br />monitoring at SW-N3 precluded the need for this site. Consequently <br />the data presented are extremely limited and no further discussion <br />is hereby provided. <br />5. Springs <br />As shown on Exhibit 1, three springs, the Highwall Spring and <br />Spoils Springs ~1 and ~'2 are monitored at the Nucia Mine. As <br />earlier discussed, a semiannual spoils spring survey of reclaimed <br />areas has been implemented as of this Septemt~er (1986). ]n the <br />course of this survey, the PCC field hydrologist responsible for <br />the Nucla Mine discovered a second spoil spring proximate to Spoils <br />Spring #1. This spring, identified as Spoils Spring ~2, will be <br />monitored according to the same program that :ipoils Spring kl is <br />monitored (see Section III. A.). <br />The Highwall Spring is located on the north face of the east <br />end of the mining pit which was left when PI;C ceased mining in , <br />the fall of 1983 as shown on Exhibit 1. Flow and Duality data <br />have routinely been collected from this site since June of 1983; <br />58 <br />