OHA Drinking Water Services
Contact Report Details |
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| PWS ID: | OR41 00062 | ||
| PWS Name: | YOUNGS RIVER LEWIS & CLARK WD | ||
| Who Was Contacted and Phone: | Bill Mitchell (503) 325-4330 | ||
| Contact Date: | 01/17/2012 | ||
| Contacted By: | HOFELD, EVAN (REGION 1) | ||
| Contact Method/Location: | Office | ||
| Assistance Type: | WATER QUALITY ALERT RESPONSE | ||
| Reasons: | Disinfection Byproducts DBPs |
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| Details: | SUMMARY: Elevated DBP levels 4th quarter 2011 DETAILS: System had elevated TTHM (0.11 mg/l) and HAA5 (0.0702 mg/l) results for sampling completed 10/19/11, although the running annual average 4th quarter 2011 was below the MCL. The system was already on quarterly monitoring due to previous RAA MCL exceedances for both HAA5 and TTHM in 4th quarter 2005 and 1st quarter 2006. The next TTHM RAA MCL exceedance occurred in 4th quarter 2010 due to high results in July 2010 (HAA5 results were invalidated by the lab in Jan 2011 and the system subsequently issued a public notice for the TTHM MCL). The RAA for both TTHM and HAA5 has been below the MCL for all other quarters between 2nd quarter 2006 and 4th quarter 2011. Bill explained that distribution looping has been improved and some modifications to disinfectant levels have been made. I completed and e-mailed a disinfection benchmark profile using 2011 data, which indicated further optimization of disinfection practices could help. Plans to cover an open reservoir in Summer 2012 are also anticipated to help reduce the chlorine demand in the system. ACTION NEEDED: System to monitor and adjust disinfectant levels as needed and continue with plans to cover the open reservoir. | ||
| Associated Alerts: | CHEM5120 - 11/01/2011 - TOTAL HALOACETIC ACIDS (HAA5) , TTHM CHEM5120 - 11/01/2011 - TOTAL HALOACETIC ACIDS (HAA5) , TTHM |
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