The City of Littleton operates both a sanitary sewer utility and a stormwater utility. In order to best maintain and operate our infrastructure, it is critical to have a full understanding of the size, needs and condition of the sewer systems, which will create an asset management program. The first step in creating a strong sewer asset management program is to inspect the condition of both the sanitary sewers and storm sewers. Since this infrastructure is underground, the inspection is done by video cameras, also referred to as closed-circuit television (CCTV).
The city has contracted with Ace Pipe Cleaning Inc. to conduct the CCTV inspection and assessment of the 128 miles of sanitary sewer mains and 48 miles of storm sewers. A camera will be run through every foot of pipe in the city, equaling about 175 miles, roughly the distance from Littleton to Glenwood Springs.
In addition in collecting video data of the sewer systems, Ace Pipe Cleaning Inc. will also be assessing the condition of the infrastructure, and document it’s exact location for the city’s GIS mapping system. Once the data is collected, the city will conduct a risk analysis to prioritize areas for maintenance and replacement in order to operate our systems most efficiently.
What’s the difference between sanitary and storm sewers?
One drain is the same as another right? The sewer is the sewer, right? Not so! It’s important to understand the difference between sanitary sewers and storm sewers so we can prevent unnecessary environmental damage.
The sanitary sewer is a system of underground pipes that carries sewage from bathrooms, sinks, kitchens and other plumbing components to a wastewater treatment plant where it is filtered, treated and discharged.
The storm sewer is a system designed to carry rainfall runoff and other drainage. It is not designed to carry sewage or accept hazardous wastes. The runoff is carried in underground pipes or open ditches and discharges untreated into local streams, rivers and other surface water bodies. Storm drain inlets or catch basins are typically found in curbs and low-lying outdoor areas.
Do you know what happens to wastewater once it goes down your drain?
- All of the drain pipes in your house are connected to one central sanitary sewer drain that goes through the foundation and out to the City main in the street.
- The pipe coming out of your house is generally referred to as a “service” or “lateral” and is the responsibility of the property owner from the house to where it connects with a larger “main” under the street.
- Typically the main is the responsibility of the City or sewer district. The City and other districts maintain a vast network of underground sanitary sewer pipes to convey wastewater to the wastewater treatment plant.
The private sanitary services (pipe between the house or building and sewer main) will not be inspected as part of this project, as it is the private property owners’ responsibility to maintain and repair.
Why is this work being done?
The CCTV inspection is being undertaken in order to gain a full understanding of the size, needs and condition of the sewer systems. It will allow the city to prioritize areas for maintenance and replacement in order to operate our systems most efficiently.
This inspection can reveal problems where the pipe is damaged or is experiencing tree root intrusion. As pipes age, they tend to become more brittle and are more susceptible to cracking as the ground shifts around them. In many cases, there are not mechanical fittings holding sections of pipe together, rather it is the soil compacted around these pipes that holds them in place. Minor shifts in soils over time may cause these joints to separate slightly. Both cases of cracking and joint separation can create an opening in a pipe that becomes attractive for tree roots seeking water. It may begin as a hairline root, but these grow and multiply, causing the crack in the pipe to become larger. Soon, a large mass of roots can develop inside a sanitary sewer pipe. The roots grow so tightly together that they can significantly block the flow of water in a pipe, creating the potential for a backup.
Common issues that may occur in the sewer systems over time may include:
- Offset joints, broken or damaged pipes
- Tree root intrusion
- Clogs from debris
Left unattended, these issues can lead to back-ups of the sanitary and storm sewers which could cause flooding of buildings, streets and other damage. Proactive identification and repair of these issues will be the most efficient and cost effective means to maintain our infrastructure for years to come.
What to Expect
There are two different groups of contractors inspecting these assets. Employees from RJN Group will be performing inspections of manholes used to access both systems. Separate employees from Ace Pipe Cleaning will be performing video inspection on pipes. There will be a number of crews and trucks throughout the city accessing the sewer systems via manholes.
The majority of the manholes are located in the street, or in the public right-of-way, like in a treelawn, however some manholes are located in back yards. For properties where the contractor may need to access a back yard, those affected residents and businesses will be notified via post card with an approximate date when the contractor will be in the area. The work does not require residents to be home, and at no time will field crews enter your home or business.
You may notice Ace Pipe Cleaning vehicles in your neighborhoods for the duration of the project. Below are example photos of their vehicles.
Work is anticipated to start Monday, June 18, 2018 and expected to take approximately 6 months to complete. Crews will likely be starting with inspection of the sanitary sewer system, generally working from north to south across the city. When inspection of the sanitary sewer system is complete, they will move on to the storm sewer system, again generally working from north to south.