1997-04-28_REPORT - M1977378 - Laserfiche WebLink

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i March 1997 Monthly/1st Quarter Report Page 4 - Cement Creek Diversion and Water Treatment Cement Creek diversion and water treatment was active continuously throughout March and the 1st Quarter. The entire flow of Cement Creek was diverted and treated along with the portal flow from the American Tunnel. During the 1st Quarter, flows diverted for treatment ranged from 167 GPM to 848 GPM. Attached are results from flow and quality monitoring 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) . As explained in the December report, there was approximately 20-30 GPM more flow at CC-20 than being discharged from the AT-004 discharge point. This water is made up of excess reagent mix water being diverted for the water treatment system from Minnehaha Creek and seeps and springs entering the creek bed between the diversion point and the CC-20 monitoring point. Mainstem Stream Monitoring and Reference Point Stream Monitoring Sunnyside sampled the reference point (A-72) on March 5, 1997. These results are attached. The provisional flow from the outside gage at A-72 for the March 5, 1997 sample was 78 cfs which is in the low flow category (Q < 100 cfs) . The reported dissolved zinc value is 755 ug/1 which is the average of results from two labs and of repeat analysis by these two labs. Repeat analysis were requested because the average resulted in an index value of 2.02. Under the terms of the Consent Decree agreement, observations with an index value greater that +2 will be reanalyzed. Index numbers for the March sample using an average of the four results is calculated as follows: Xi = 755 Xf = 519 Sf = 124 Ni = (Xi-Xf)/Sf Ni = (755-519)/124 Ni = 1 .90 The index number graph and updated reporting table are attached.