While the September 2019 flood wreaked havoc on Mitchell, it is helping city leaders prioritize drainage infrastructure projects in flood-prone areas.

Neighborhoods in the area of lake — which are reliant on septic tanks and one lift station for stormwater drainage — will benefit from a $2.8 million project that will replace the 1997-built Dailey Drive lift station that services most of the residents living on the northwest corner of the lake. Homeowners in that area have had issues with flooded basements because the lift station has been reaching capacity, a situation only made worse when historic rainfall falls like in 2019, when 7 to 8 inches of rain dropped in a 48-hour span.

Although the low-lying area along South Kimball Street and East Hackberry Avenue have been hit hard by severe rain events and is being addressed through the East Central Drainage Project that the city has prioritized, residential areas on the other end of the city are getting their share of attention.

“The new location of the lift station and increased capacity should give those residents and the city peace of mind when heavy rain events hit,” said Mitchell Public Works Director Joe Schroeder.

The scope of the Dailey Drive lift-station project entails replacing the existing one that sits on the corner of Dailey Drive and 407th Avenue with a new lift station across the street on North Harmon Drive. Schroeder said the project is about 40% complete and estimated to wrap up in 2022. He noted the existing lift station will transform into a manhole for crews to perform maintenance when needed.

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Lift stations have pumps that move stormwater and wastewater, which flows into a tank and gets pumped out to the sewer lines throughout the city. As the lift stations throughout the city age, Schroeder improving them is vital to improve drainage and minimize flood impact.

According to Terry Aker, civil engineer with SPN and Associates, the typical life expectancy for the city’s lift stations hover around 30 years, and Mitchell has several that are 50 years or older. Of the 14 lift stations in Mitchell, Aker said at least 12 were in need of some sort of improvement during his presentation of a sewer system evaluation he gave to the City Council roughly two years ago. The cost of improving all 12 of the lift stations to handle more water capacity at that time, including Dailey Drive’s lift station, was estimated at $7 million.

Near Dailey Drive lift station project is another area set for infrastructure upgrades in 2022, where the city is taking on the Livesay Utility Improvement project. That will entail providing storm sewer lines for future residents in the area along Michael Avenue to connect to instead of relying on septic tanks and newly paved streets. The residents who live along Anthony Avenue, which is a block south of the new Michael Avenue, will rely on septic tanks for storm-water drainage after those residents recently struck down a special assessment.

“The reason this project came along is that Anthony Avenue does not have storm sewer, and we get complaints about water in the ditches,” Schroeder said, noting the project will also bring culverts to improve drainage. “We’re providing storm sewer for those future developments to the north so we don’t run into the same issue. We are talking about a connection fee in order for the city to recoup some of our costs.”

Septic tanks are typically built underground and only service the home of a resident. Since septic tanks have less wastewater capacity than city sewer lines, a home that relies on one can flood more easily than a home that’s connected to a sewer line.

“It’s a huge benefit for the homeowners because they don’t have to worry about their septic tank flooding and sewage in their yard. It’s just a win for everyone to have city sewer lines to connect to,” he said.

Residents living along Anthony Avenue will soon have a paved road replacing the existing gravel, which is another step toward enhancing drainage. Schroeder said Anthony Avenue will be paved following the completion of the utility work that’s estimated to wrap up in roughly a year from now.

Replacing century-old pipes

Another key issue that Schroeder said needs to be addressed to improve the city’s drainage is replacing near century-old pipes. After a local engineering firm presented results of a sewer system evaluation that showed the corroding conditions of Mitchell’s old water and sewer pipes, city leaders have used it to hone in on areas that are in dire need of pipe replacements.

“It’s a huge element to improve our utility infrastructure. Reducing the clay pipe reduces our infiltration from stormwater events,” Schroeder said. “Right now, we’re trying to tackle 4-inch cast iron water mains to help improve water volume and pressure in areas that have really old pipes.”

According to Aker, about 60% of the city’s roughly 500,000 feet of sewer mains are made out of clay pipe. To replace the 300,000 feet of clay pipe, Aker said it would cost roughly $61 million.

Considering the city’s proposed $75.5 million expenditures in the 2022 budget that’s yet to be approved increased by $10 million compared to 2021 is largely driven by the major infrastructure projects, Council President Kevin McCardle said the projects are “well worth the investment.”

“If we don’t fix the old infrastructure we have now, it will cost way more down the road and lead to more problems in the meantime. We have miles of pipes that are 100 years old,” McCardle said. “We’re focused on growing Mitchell, but you can’t grow if your infrastructure can’t handle the current population.”

Schroeder said some of the cast iron water pipes the city is planning to replace date back to the early 1900s. They will be replaced with modern plastic pipe.

In the 2022 budget, the city is proposing to improve a portion of East 10th Avenue, stretching from North Lawler to North Langdon streets by replacing cast iron water pipes and vitrified clay sewer pipes. The $955,000 project would also entail extending the street by about 10 feet.

"We're replacing the 4-inch cast iron water main with 6-inch vitrified clay pipe. We've had water main breaks within this area," Schroeder said, noting the street will be extended to a width of 41 feet. "It will bring new curb and sidewalk as well, so it's a good project."