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Inflow and Infiltration

Investing in our local infrastructure is crucial for our community's health and prosperity. Oak Lodge Water Services (OLWS) is working to update its collections pipes to keep providing safe and reliable service for years to come.

The OLWS collections system has a problem with extra rainwater getting into it, which can cause sanitary sewer overflows. This happened recently at Lift Station 2 when our community experienced heavy rain. Under normal, dry weather conditions, the flow into the wastewater treatment plant is 3 million gallons per day (MGD). However, during wet weather events, the flow into the plant can surge to as much as 15 million gallons per day (MGD).

To address this problem, OLWS is actively taking steps to reduce the infiltration of excess rainwater into the system. There are 34 places in the collections pipes near Lift Station 2 and Trunk Main A that need to be repaired or replaced. Some of these pipes are on private property, while others are in public areas owned by Clackamas County. Based on inspections, most of the repairs can be done without digging deep open trenches. Instead, methods such as cured-in-place pipe or pipe bursting can be used.

OLWS has conducted closed-circuit television inspections on 98 percent of the collections system piping. The pipe condition information has been used to represent the likelihood of failure of those pipes. OLWS is working to minimize the risk of failure. In Figure B, a map of the OLWS service area visually represents each pipe, color-coded to indicate its individual level of failure rating.

Level of Failure Key

  • Level 1 - Excellent: Minor Defects. Failure is unlikely.
  • Level 2 - Good: Defects which are unlikely to fail for at least 20 years.
  • Level 3 - Fair: Moderate defects that will continue to deteriorate in 10 - 20 years.
  • Level 4 - Poor: Severe defects that will become grade 5 within 5 - 10 years.
  • Level 5 - Immediate Attention: Defects requiring immediate attention, which have failed or will likely fail within the next 5 years
May contain: chart, plot, diagram, plan, map, and atlas
Figure B from the Nov/Dec Customer Newsletter 
Inflow and Infiltration Project in the Lift Station 5 Basin Area 

(October 12, 2023) – We have started preparing for construction in the Lift Station 5 Basin Area. Construction is planned to begin in Spring 2024. Below is a map of the project area. 

Lift Station 5 - Project Area



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