1999-11-29_HYDROLOGY - M1977378 - Laserfiche WebLink

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October 1999 Monthly Report Page 4 will, on a temporary basis, resume Cement Creek diversion and treatment in November as outlined in our letter dated November 2, 1999. The September, 1999 monitoring results for; dissolved metals in the AT-004 discharge; Cement Creek (CC-1); American Tunnel flow before treatment (AT-INFEL); and Cement Creek below the AT-004 discharge point (CC-20) are attached to this report. Since Sunnyside was not diverting and treating Cement Creek in October, the reported values (CC-1) are quality and flows for Cement Creek near the diversion. Mainstem Stream Monitoring and Reference Point Stream Monitoring Sunnyside sampled the reference point (A-72) and the other three gaging stations (A-68, M-34, and C-48) on October 6, 1999. Results from these samples are attached. The provisional flow at A-72 on October 6, 1999 was 284 cfs, which places this sample result in the intermediate flow category (100<Q<300cfs). The dissolved zinc value for this sample, obtained by averaging the results from two labs, was 545 ug/l. The index number for the October sample is calculated as follows: Xi = 545 Xf= 399 Sf= 144 Ni = (Xi — Xf)/Sf Ni = (545 — 399) /144 Ni = +1.01 The index number graph and updated reporting table are attached. Evaluation of the normalized data: The index value of +1.01 for October, 1999 indicates that the dissolved zinc concentration at the reference point A-72 was significantly higher than the mean value of the reference data for the intermediate flow class. In comparison to the October 7, 1998 sample result, the concentration is higher(545 ug/l verses 401 ug/1) and the flow also higher (284 cfs verses 113 cfs), although in the same flow class. The monitoring results for A-68 and C-48 indicate that both drainage basins had elevated dissolved zinc concentrations in October.