project details

A functioning sewer mainline is critical for preventing sewages backups and other potential health hazards that can harm public health. The Molalla Avenue I&I Rehab Project is one project, of several, to improve the city's sanitary sewer system. Specifically, this project involves repairing sewer main and lateral lines  along Molalla Avenue and several connected side streets, from Division Street to Hilltop Avenue as part of the City's Inflow and Infiltration Reduction Program.  To accomplish this, several construction methods will be utilized in an effort to reduce impacts to the community during construction. 

This project includes:

• Repairing approximately 1.8 miles (or 9,300 linear feet) of sewer mainline.
• Replacing approximately 600 linear feet of sewer.
• Inspecting, repairing and/or replacing about 240 sewer lateral pipes in poor condition.
• Installing six (6) new manholes.

Whenever possible, low excavation methods will be used, such as pipe bursting. This method minimizes disruption to the surrounding area. On Molalla Avenue, sewer mains and lateral lines will be rehabilitated/repaired using various methods including trenchless CIPP to the maximum extent possible. Special measures will be taken to ensure construction does not impact student pickup, or drop-off at Gardiner Middle School. To accommodate this, the following items have been established for the project construction: 

• Restricted Work Hours – Work is only permitted along bus routes, and major parent pickup/drop off routes, from 9 AM to 3:30 PM on school days, except Wednesdays. Wednesday work hours will occur from 9:00 AM to 2:30 PM. 
• Bus Prioritization – Busses will be allowed to pass through work zones, and along bus routes without delays.
• Direct Coordination – Coordination with the school district and Gardiner Middle School will continue throughout construction.

Measures Taken to Reduce Impacts to the Community

Keeping traffic flowing along Molalla Avenue is a priority! The following measures will be taken to reduce traffic delays and reduce impacts to businesses in the area. 

• Special Traffic Control Plans – Traffic control devices (traffic cones, signs, and barriers) and the number of flaggers (workers who direct traffic through work zones) were established as part of the approved construction plans and aim to ensure safety and traffic flow. 
• Restricted Work Hours and Night Work – Construction work on Molalla will only occur during daytime hours, between 9 AM and 3 PM, Monday through Friday. Night work may be necessary, if the contractor cannot reasonably finish a task within the defined daytime hours. If nightwork is necessary, plans will be made accordingly. 
• Molalla Avenue Work To Be Completed First – Molalla Avenue construction will be completed first, to minimize impacts to school bus operations.
• Mainline and Lateral Rehabilitation (Rehab) – All sewer main and lateral lines, within Molalla Avenue, will be rehabilitated using construction methods to (wherever possible) avoid digging within Molalla Avenue. This will allow construction to be completed faster and to keep more traffic lanes open during construction. 

OTHER PROJECTS IN THE AREA

While the  I & I project addresses sewer repairs,  the Molalla Transmission Main WIFIA 3-1 Project project addresses water repairs. The water project is part of the federal Water Infrastructure Finance and Innovation Act (WIFIA) Program and is expected to complete construction this winter (2025). Water work in Molalla Avenue will not begin until the I & I sewer work is finished in the area.  

There will be two informational meetings held in June for the WIFIA project: June 4th (7-8PM)  In-person meeting and June 6th (12- 1 PM) virtual meeting. 

HOW WILL THIS PROJECT BENEFIT THE CITY?

The Molalla Avenue Sanitary Sewer I & I project repairs and rehabilitation work will ensure proper wastewater flow, extend the lifespan of the sewer line, and save money (to both the city and utility customers).  This ensures public health and safety, which is always a priority! 

Through the City's Lateral Program, the City will repair, or replace, deteriorated private sewer lateral pipes at no cost to eligible property owners - a cost which is usually the property owner's responsibility. 

How do I enroll in the Lateral Program? 

Through the I & I Program, the City identifies which sewer lateral lines will be impacted by an I&I project. A notification letter and Right of Entry Form are then mailed to the property owner(s) who may be impacted by the project(s).  The property owner(s) must sign the Right of Entry form and return it to the City to enroll in the Lateral Program. Once enrolled, the property owner(s) will receive a free inspection of their lateral line - performed by the contractor hired by the City for the specific I & I project.  

If the City discovers that I&I is being created (i.e. obvious cracks/gaps, materials known to leak, etc.), the City will propose a lateral rehabilitation plan, including repair and restoration/cleanup to the property owner.  Once a plan has been agreed upon (between City and Property Owner), with the City accommodating as much as possible, the property owner will receive a new or rehabilitated lateral line. The new or rehabilitated later line will be fully paid for by the City.

Time is Running Out to Enroll in the Lateral Program! 

Although construction is well on its way, eligible property owners can still sign up for the Lateral Program.  If you are a property owner (within this project area) and have not received a Right of Access and Entry form, have not signed and returned the Right of Access and Entry form, need a replacement form, or have any questions about the Lateral Program in general, please contact the project manager.  

The City will accept Right of Access and Entry forms throughout construction; however, if you don’t sign up for the Lateral Program before construction ends, there will not be another opportunity to receive a free lateral inspection or repair! 

i & i DICTIONARY

This project is part of Oregon City’s Inflow and Infiltration Program (I&I Program) - a program created to address stormwater and ground water entering the city's sanitary sewer system.  To understand the I & I program and this project, several key terms are defined: 

Groundwater is a naturally occurring source of water located below the ground’s surface. It can be impacted by stormwater (rain, snow) that soaks into the ground filling the tiny spaces between rocks, sand and dirt under the surface. Groundwater levels fluctuate throughout the year as the seasons become more wet (high groundwater level) or dry in the summer (low groundwater levels). It’s like water hiding in a sponge, but underground! 

Infiltration happens when groundwater leaks into the underground public sewer system through cracked pipes, broken manholes or improperly connected roof drains. Infiltration increases during winter and spring when groundwater levels are high. This increase can overload the sewer system, leading to backups and system failures. Because this additional water must be treated at the wastewater treatment plant, it increases costs for both the city and utility customers. Oregon City utilizes the Clackamas County Water Resource Recovery Facility, which is designed to handle higher flows. 

Inflow is when surface stormwater enters the sanitary sewer system through direct connections such as downspouts from roofs, sump pumps, or improperly connected stormwater pipes. Inflow can significantly increase flows during rainstorm events - potentially overloading the sewer systems and leading to sewage backups. Like infiltration, inflow raises treatment and maintenance costs, while placing additional strain on wastewater facilities. More critically, it threatens both environmental and public health. Inflow is the primary cause of peak surges in sewer flow during storm events.  Oregon City currently experiences high levels of Inflow due to old stormwater collectors that were connected to the sanitary sewer system before codes changed which is no longer allowed. During the winter and spring, most flow in the sanitary systems comes from Inflow and Infiltration (I & I). However, newer sections of the City’s system have very low levels of I&I year-round.

Lateral Lines (laterals) - Sewer laterals are small pipes that connect a home or business to the public sewer system. These pipes carry wastewater or stormwater away from the buildings into the public mainline sewer systems which then transport it to the city's wastewater treatment facility for processing.  Typically, each home or business has a single sewer lateral.  In Oregon City, maintenance of sewer laterals is divided between the property owner and the City.  The City is responsible for the section of the lateral line that runs from the public mainline to the back of the sidewalk (in most cases). The property owner is responsible for the section that runs from the edge of  the (if the sewer main is under the road), or from just past the connection point between the lateral line and the sewer main More information can be found in the City's Sanitary Sewer Lateral Policy. For properties that are eligible for the City's Lateral Program, the City will pay for repairs or maintenance.

Main lines are large pipes within the city's water, sanitary sewer and stormwater sewer systems designed for higher volumes. Sewer mainlines connect to the (smaller) lateral lines to transport wastewater to pump stations or treatment plants to remove contaminants. 

Manholes are below ground structures used to access the City’s sewer systems for inspections and maintenance. You can identify manholes by the large round metal lids typically found within the roadway. Manholes are also used to change the direction of sewer pipes (like turning a corner); shift pipes from one side of the road to the other, or to combine flows (from two or more pipes into one main pipe (done for sanitary and storm sewer systems). 

Public Right of Ways (ROW) are portions of land dedicated for use like sidewalks, roads, and access to public utilities (such as water, sewer, etc.). Government agencies (city, county, state) are responsible for maintaining and managing these spaces. Think of it like the Oregon City Public Library. The city (government) owns it, but everyone can use it, and the city workers are like janitors who keep it clean, safe and working properly. The ROW is a shared community space and is protected by important rules and regulations. 

Rehabilitation (Rehab) restores the current system by improving the conditions to help make them last longer.  I & I rehab restores existing sewer pipes or manholes, at their current locations, using different construction methods. Rehab improves the conditions to help make them last longer. 

Repairs, unlike rehabilitation, are long-term solutions.  These can include full pipe replacements, new paving, etc. For the I & I program, repairs fix the system by removing most (or all) existing sewer pipes or manholes and replacing the removed portions with brand new materials using pipe bursting and trenching construction methods. 

Sanitary sewer lines are underground pipes that carry wastewater away from buildings (homes, businesses, etc.), to be treated at a treatment plant. 

Sewage is a type of wastewater that typically contains human waste. Oftentimes the term sewage and wastewater are used interchangeably but not all wastewater contains sewage.  

Sewer Systems consist of all the parts that make up the city's sanitary and stormwater collection systems. These include pipes, manholes, and pumps that are maintained by the city to transport different types of water (stormwater and sewage). Note: Sanitary Sewer Systems and Stormwater Sewer Systems are two different collection systems. 

Stormwater is rainwater that flows into gutters and the stormwater sewer system. As the water runs off rooftops, streets and other hard surfaces, it can collect dirt, oils, and debris, becoming polluted. To help clean this runoff, the city uses specifically designed raingardens, ponds, planters and other structures to treat the water before it releases back into the environment.

Stormwater collectors collect rainwater or channel rainwater. Examples include catch basins and roof gutters. 

Streetscape is broad term for the various components that make public spaces more welcoming.  While streets provide access from one place to another (focused on movement), streetscapes provide the experience and overall look of an area that can define a community’s identity, economic activity, social cohesion, public health, and quality of life (to include mobility). This is achieved by adding things such as street trees, planters, street furniture (i.e. trash receptacles, benches), sidewalks, and streetlights. Special elements can include public art, water fountains and drinking fountains.

Treatment is the process to remove pollutants from wastewater to make the water safe for reuse or release into the State’s waterways.

Wastewater is a combination of sewage and dirty/used water from toilets, sinks, washers, showers and other household or commercial sources. This water travels through the sanitary sewer system - which includes lateral lines and main lines - to a treatment facility.  

Wastewater Treatment Facilities (also referred to as "wastewater treatment plant" or "sewage treatment plant") are the locations where wastewater is treated (cleaned) to remove harmful substances (like human waste, chemicals, and food scraps). Once cleaned, it is safe enough to be sent back to the natural water cycle (usually into rivers or oceans) or be reused for things like irrigation.  

project DOCUMENTS & WEBLINKS

DOCUMENTS

• Project Information Sheet
• Right of Entry Letter and Form Sample

WEBLINKS

• Learn more about the Inflow and Infiltration Program
• Methods used to address Inflow and Infiltration
• City Projects Map
• Traffic Impact Maps for Capital Improvement Projects