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OHA Drinking Water Services
Contact Report Details |
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| PWS ID: | OR41 00338 | ||
| PWS Name: | GRAND RONDE COMMUNITY WTR ASSN | ||
| Who Was Contacted: | Karl Ekstrom | ||
| Contact Phone: | 503-879-5624 | ||
| Contact Date: | 01/03/2023 | ||
| Contacted By: | CIVIL WEST ENGINEERS, INC (DWP) | ||
| Contact Method/Location: | Field | ||
| Assistance Type: | CIRCUIT RIDER ASSISTANCE | ||
| Details: | Background/Problem Identification: System needs help with system troubleshooting after repeated positive test results for coliform. Assistance Provided: Dan Vaage visited the site to assess potential sources of coliform intrusion. The water system “pulls” from seven spring sources. Several of the spring collection boxes (cylindrical manhole style) had venting issues and deteriorated grout lines that could be potentially pulling in contaminated material. It was also noted that several of the spring collection boxes had “burp” flap valves on their effluent side that had the potential for pulling in fallen organic material from overhanging trees during the vacuum cycle of the “burp”. We recommend making the necessary venting and grout repairs to all spring collection boxes. The burp valves should be reconfigured in a manner that does not allow for fallen materials to enter the pipes (i.e. facing downwards/screened off). It may also be beneficial to install sampling ports on the effluent lines of each spring source to determine which spring source has coliform issues. We also noted an undersized PRV downstream of the springs that was likely inducing significant air into the system via cavitation. It is recommended that an appropriately sized PRV be employed, or a second PRV be utilized that will allow the pressure to be reduced to a reasonable level prior to the existing PRV. Follow-Up Actions Needed: The circuit rider can assist further as needed. Technical Reports to be Prepared and Expected Timeframe: N/A |
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