|
|
| Introduction :: Data Search Options :: Water System Search :: DWS Home :: DWS Rules |
OHA Drinking Water Services
Contact Report Details |
|||
| PWS ID: | OR41 00236 | ||
| PWS Name: | COTTAGE GROVE, CITY OF | ||
| Who Was Contacted and Phone: | Ray Pardee (541) 228-0179 | ||
| Contact Date: | 12/01/2014 | ||
| Contacted By: | BURNS, LAURA C (DWP) | ||
| Contact Method/Location: | Office | ||
| Assistance Type: | OTHER REGULATORY - REGULATORY ASSISTANCE | ||
| Reasons: | SWTR Operations |
||
| Details: | SUMMARY: Ray Pardee contacted DWS about exceeding the allowed flow rate from the Tracer Study. DETAILS: On 11/26/14 there was a pipe break (no associated loss of pressure and chlorine residual was maintained) that increased the flow from the Knox Hill reservoir to 6288 gpm for about 1 hour. The Tracer study results are valid for a maximum flow rate of 2420 gpm. The flow rate from the WTP to the Knox Hill reservoirs was not affected. A Tracer Study completed in 2009 from the WTP to the Knox Hill reservoirs credited 54 minutes. Since the flow rate was not increased in this area the contact time to Knox Hill would still be 54 minutes. The actual CT would be 37.8 minutes (lowest chlorine residual of 0.7 ppm) and the required CT is 21 minutes. CT was met. I instructed Ray to use 54 minutes of contact time for 11/26. This is a conservative calculation and does not include any contact time in the Knox Hill reservoirs. Since CT"s were met a Public Notice is not required. Note: The pipe break was between a main and a fire hydrant. ACTION NEEDED: Ray will contact Casey to determine if they can use any contact time from the Knox Hill reservoirs if they exceed the max flow rate in the future. | ||