1997-08-25_HYDROLOGY - M1977378 - Laserfiche WebLink

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July 1997 Monthly Report Page 4 The water pool pH at the American Tunnel bulkhead on July 23 , 1997 was 4 . 72 and the bulkhead pressure was 307 psi. This observed pH rise occurred prior to the start of alkaline injection. - Cement Creek Diversion and Water Treatment Cement Creek diversion and water treatment was active continuously throughout July. Due to Cement Creek flow quantities, diverted flows for water treatment from Cement Creek were controlled throughout July. These treated flows ranged from 1139 GPM to 1223 GPM. Results for June monitoring samples of Cement Creek diverted for treatment (CC-1B) ; American Tunnel flow before treatment (AT-INFEL) ; dissolved metals analysis of the AT-004 discharge; and Cement Creek below the AT-004 discharge point (CC-20) are attached. July results were not received by the date of this report and will be submitted with the August report. - Mainstem Stream Monitoring and Reference Point Stream Monitoring Sunnyside sampled the reference point (A-72) on July 9 , 1997 . The other three gaging stations were sampled by the BOR. The provisional flow from the outside gage at A-72 for the July 9, 1997 sample was 705 cfs which is in the high flow category (Q > 300 cfs) . The reported dissolved zinc value is 244 ug/l which is the average of results from two labs. The BOR July 9 , 1997 sample results for the gaging stations were 330 ug/l for A-68 , 95 ug/1 for M-34 and 680 ug/1 for C- 48 . All sub-basins and the reference point A-72 appear to have been at or below average zinc concentrations in July. Flows at A-72 have been adjusted for April, 1997 through June, 1997 based on input from the USGS who operate the gage. These adjustments did not cause a flow class change for any of these previously reported months. The index number for the July sample is calculated as follows: Xi = 244 Xf = 306 Sf = 104 Ni = (Xi-Xf) /Sf Ni = (244-306)/104 Ni = -0. 60