While the city of Mitchell’s sewer system is in need of improvements, it is not projected to be a cheap venture.
The Mitchell City Council was informed Tuesday night of the hefty price tag that would come with improving much of the city’s sewer system, coming in at an estimated cost of $122 million.
That’s according to Terry Aker, civil engineer of SPN and Associates, who provided the results of an evaluation the engineering firm recently completed, which took an extensive look at the city of Mitchell’s sewer system. The council received the sewer system update as part of a discussion on agenda, and no action was taken.
“In the worst case scenario, it would be over $122 million of improvements, and it’s nothing you’ll tackle in five to 10 years, but it needs to be on your radar,” Aker said.
According to Aker, there are about 500,000 feet of sewer mains in the city of Mitchell. Of that, roughly 60% of the sewer mains are made with clay pipe, equating to roughly 300,000 feet of clay pipe, which would cost an estimated $61 million to replace.
“In our experience with clay pipe, it’s generally 50 years or older, and a lot of it is cracked and has misaligned joints,” Aker said, noting it as a major issue with the existing sewer system. “It cracks and sags, and it is generally not in good condition.”
In the event of a heavy rainstorm, Aker said the clay pipes, at times, don’t have the ability to handle large amounts of water infiltration, causing water to bypass the city’s lift station.
Lift stations are used to pump wastewater or sewage from a low level to a higher level when the area where they’re placed doesn’t allow for natural flow.
“There are areas of high maintenance that the city crews have to clean and jet to maintain flow in the sewer system,” Aker said, noting the evaluation also identified several undersized water mains.
Aker recommended the city to televise the entire sewer system, which entails a robotic device that travels through the sewer system to allow the city and engineering firm to get a close-up look at the conditions.
Roughly 2% of the city’s sewer system has been televised, Aker said. To televise the entire sewer system is estimated to cost roughly $2 million.
“One of our recommendations is to clean and televise the entire sewer system, because that way we would have a better idea of what’s actually there. A lot of times it is eye-opening and verifies what does need to be replaced,” Aker said. “This gives you a very accurate view of what’s there.”
Aker said there is about 12,000 feet of pipe the city has to clean multiple times per year. In addition, that 12,000 feet includes relocating a sewer main that runs underneath The Depot Pub and Grill.
To replace the 12,000 feet of pipe would come in at a cost of $4.9 million, he said, while providing a map to the council.
A water study that SPN and Associates completed roughly two years ago recommended the city replace the cast iron and asbestos water mains.
“If you’re already digging up the water main, you might as well replace the sewer right next to it,” Aker said, noting replacing the cast iron pipes would cost $24.5 million, while the asbestos pipelines would be $11 million.
Aker said the evaluation found several undersized water mains, which affect the ability to handle water flow. The Foster Street lift station stretching north is the area that is experiencing the most drainage backups, according to Aker.
The 14 lift stations scattered throughout the city of Mitchell, Aker said, also could use some upgrades. Aker said 12 of the 14 lift stations are in need of some type of improvement, which is estimated to cost a combined $7 million.
“Some of the issues we found were undersized lift stations, and some are simply outdated and have odor issues,” Aker said.
According to Aker, a typical lift station life expectancy is around 30 years, noting Mitchell has several that are 50 years or older. The Dailey Drive lift station is the top priority for replacing, he said.
“It might be $80 to $90 million if we televise the system, but I’d rather give you the worst case scenario,” Aker said.
Mitchell Mayor Bob Everson is aware the cost is significant, but he said the city needs to keep its focus on the sewer system improvements for the future. There is no definitive timeline of when the sewer improvement project would take place.