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OHA Drinking Water Services
Contact Report Details |
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| PWS ID: | OR41 06049 | ||
| PWS Name: | SOUTHVIEW IMPROVEMENT DIST | ||
| Who Was Contacted: | Wayne Niederjohn | ||
| Contact Phone: | 541-991-3873 | ||
| Contact Date: | 01/04/2021 | ||
| Contacted By: | CIVIL WEST ENGINEERS, INC (DWP) | ||
| Contact Method/Location: | Field | ||
| Assistance Type: | CIRCUIT RIDER ASSISTANCE | ||
| Details: | Background/Problem Identification: SID has had a recent issue with positive coliform “hits” in distribution. The system had not had any issues with coliform since 2010. SID recently had work done on the pressure reducing valves (PRVs) in the distribution system. Many other possible sources of coliform were identified. Assistance Provided: The circuit rider reached out to Wayne Niederjohn and scheduled a site visit on 01/20/2021. The water system consists of a well that pumps to a 69,000 gallon reservoir. The reservoir supplies water to a booster pump that supplies pressure to several houses local to the reservoir in elevation. The remainder of the distribution system is pressurized via gravity and employs several PRVs and related pressure zones. The following possible coliform sources were identified: • SID recently had work done on the pressure reducing valves (PRVs) in the distribution system. Shortly after this work was completed, positive coliform results were recorded. o It is possible coliform was introduced to the system during the repairs and proliferated in the biofilm lining the distribution piping. It is also possible that the repair work “shook loose” coliform containing biofilm in the distribution piping and this shedding of the biofilm could be the cause of the repeated positive coliform tests. • SID recently had their reservoir inspected, inside and out. As a result of this inspection, MIT diving found the following possible issues: o Delamination of interior wall seam gasket material o Fine mesh screen on tank vent missing/dislocated o Possible debris/droppings on roof seam • The reservoir has a ~27’ long “dead-end” drain line that is not in service due to fears that the aged valve at the effluent end of the drain line may either break, or not fully close after opening. o The dead-end line may be a stagnant zone that may harbor biofilm/coliform growth • The reservoir is quite large for the size of the service population/water demand. o Stagnant |
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