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Antonia K.J. Vorster -2- 10 July 1985 <br /> 4. At 26 mgd, the effluent dechlorination capacity is about five ppm. <br /> 5. On 19 and 20 June there was a large amount of storage capacity available in <br /> the tertiary ponds. <br /> 6. Dead waterhyacinths, from a pilot project in the ponds which has been <br /> terminated, may have contributed BOD, nitrogen, and solids to the tertiary <br /> system, adding to chlorine demand. <br /> 7. The Department of Fish and Game (DFG) has estimated that 5,000 catfish were <br /> killed. They estimate 1/2 pound per fish at a replacement cost of $2.00 <br /> per pound, totalling $5,000.00. They do not plan to restock. <br /> B. Although the City suggested that the low Dissolved Oxygen (D.O. ) con- <br /> centration killed the fish, DFG believes that the fish kill was not caused <br /> by low D.O. DFG searched the City' s records and of receiving water <br /> monitoring and found no D.O.s low enough to be toxic to catfish. <br /> SUMMARY/CONCLUSIONS <br /> Based upon: 1) the magnitude of the violation of pH and chlorine requirements, <br /> 2) the effluent comprising 2/3 of total river flow, and 3) the timing of the <br /> fish kill , I conclude that the City of Stockton caused the fish kill . <br /> I believe that the City of Stockton was negligent because: <br /> 1. The City could have prevented the discharge in violation of requirements, <br /> and the fish kill by ceasing the discharge and instead using available pond <br /> capacity. City personnel were aware of serious pH and chlorine violations <br /> by 1700 hours on 19 June, less than two hours after breakpoint chlorination <br /> was attempted. The discharge continued for over 24 hours. <br /> 2. If the City of Stockton had sufficient dechlorination facilities, the <br /> illegal chlorine discharge would have been prevented. <br /> 3. If the multi-media filters had been operable and operating, chlorine demand <br /> would have been reduced, and the chlorination problems might have been <br /> averted. <br /> 4. The City either was unaware of or disregarded river flow conditions which <br /> were such that plant flow was over 2/3 of total river flow. <br /> 5. The City either was unaware of or disregarded the potential for chlorine <br /> violations resulting from attempting to reach breakpoint chlorination. <br /> DTW:jec <br /> Attachment <br />