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the ash lagoons. The water overflowed the control structure resulting 

 in a 6,119 m^ maximum discharge to Cookson Reservoir. Analyses of the 

 reservoir waters indicated rapid and complete mixing as no change in 

 water quality was evident. Cleanup measures were implemented. Sub- 

 sequent thickness testing of the ash lines indicated that the bottoms 

 of the lines were wearing as a result of erosion. The ash lines 

 between the plant and the ash lagoons have since been rotated 180 

 degrees to extend life and prevent spills. 



On October 17, 1986, a seam on a buried section of the recirculation 

 line failed, spilling approximately 2,000 m^ of ash recirculation 

 water into the same area as the previous spill. The spill was con- 

 tained upstream of the control structure. No recirculation water 

 entered the reservoir and cleanup measures were implemented. Routine 

 water quality monitoring of the runoff waters collected by the control 

 structure is an ongoing practice prior to their release. 



Construction 



Seven concrete and steel V-notched weirs were constructed in surface 

 runoff channels downstream of the Morrison Dam and spillway. The 

 weirs, completed in June 1986, replaced old plywood and earth 

 structures which had deteriorated beyond use. The weir flows are 

 routinely measured and recorded to monitor seepages from Morrison 

 Dam. 



The Ash Lagoon No. 3 North water return structure was completed in 

 July 1986. The concrete and wooden stoplogged structure will permit 

 the controlled flow of clear waters from Ash Lagoon No. 3 North to 

 the Polishing Pond. 



