OHA Drinking Water Services
Contact Report Details |
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| PWS ID: | OR41 00799 | ||
| PWS Name: | SEASIDE WATER DEPARTMENT | ||
| Who Was Contacted and Phone: | Ben Davis (503) 738-5112 | ||
| Contact Date: | 11/25/2009 | ||
| Contacted By: | HOFELD, EVAN (REGION 1) | ||
| Contact Method/Location: | Office | ||
| Assistance Type: | OTHER REGULATORY - REGULATORY ASSISTANCE | ||
| Reasons: | SWTR None |
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| Details: | SUMMARY: CT and regulatory assistance DETAILS: Ben had thought that they did not meet CT on 11/19 and 11/23, however, they had been using contact time estimates from the manufacturer and derived from a 2008 water system survey. The survey estimated a clearwell baffling factor of 50% due to the configuration and a contact time of 48 minutes at 2,800 gpm. The survey also indicated that a tracer study was required. Tracer studies conducted after the survey at 2,400 gpm and 2,800 gpm demonstrated contact times of 115 and 94 minutes, respectively. Factoring these contact times into the CT calculation revealed that CT was met on 11/19 and 11/23. ACTION NEEDED: System to begin using contact time derived from the tracer studies. No treatment techniques were violated. | ||