A downtown drainage improvement project will close portions of Central Avenue this summer.

Initially, the city planned to work in alleys and side streets, but as they designed the project and considered a “multitude of options,” engineers determined they’ll have to close Central Avenue from 2nd to 4th Streets, in half block increments to ensure continued business access.

Josh Sommer, of Great West Engineering, the city’s consultant on the project since 2020, said that they determined upsizing stormwater infrastructure in the alleyways was the focus but determined to be impractical, so they’ll instead work in Central Avenue.

The city retained Great West Engineering in 2020 for a basin study.

Downtown drainage project to close another intersection, block [2025]

The 9th Avenue South and Central Avenue/4th Street drainage basin study was completed in December 2020, identifying system deficiencies and recommended improvements to the storm drain network to reduce duration and amount of future flooding.

The project was broken into four phases.

The first phase of Central Avenue/3rd Street drainage improvements project was constructed in 2023 with final payment approved by commissioners in August 2024.

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The second phase, completed last summer, included storm drain improvements along 3rd Street South between 2nd Alley South and Central Avenue to include storm drain, water main and street improvements along 1st Avenue South between 3rd Street South and 5th Street South.

The final phase will be done in 2027 with an outfall to the river in the area of MacKenzie River Pizza, Sommer told commissioners during their Feb. 3 work session.

The original scope of phase three, which will be constructed this summer, was to:

• replace and upsize the storm drain in 3rd Street North from 1st Alley North to 2nd Alley North
• replace and upsize the storm drain in 1st Alley North from 2nd Street North to 4th Street North
• replace and upsize the storm drain in 2nd Alley North from 2nd Street North to 4th Street North

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The updated and expanded scope of work incudes:

• upsizing the storm drain and adding a parallel line in Central Avenue from 2nd Street North to 4th Street North
• installing new storm drain on 2nd Street North from Central Avenue to 1st Alley North
• new storm drain on 4th Street North from Central Avenue to 1st Alley North
• new storm drain on 5th Street North from Central Avenue to 1st Alley North, from 2nd Alley North to 2nd Avenue North
• water main replacement on Central Avenue from 2nd to 4th Street; and 2nd Street North from Central Avenue to 1st Alley North
• street reconstruction on Central Avenue from 2nd to 4th Street; and 2nd Street North from Central Avenue to 1st Alley North

The alleys are congested with other utilities, including fiber optic, gas, sewer, power lines, existing storm drains and sewer lines, Sommer said, and storm drain replacement in the alley would be very difficult, high risk and costly.

Shifting the work to replace storm drains in Central Avenue removes about 12,000-square-feet worth of concrete removal and replacement, allows for replacement of deteriorating water main and street reconstruction, reducing overall construction time, eliminating work on 3rd Street and saving about $500,000, Sommer told commissioners.

Sommer said the Great West team and city staff would present the plan to the downtown groups and businesses in the near future and provide affected downtown businesses regular construction updates when the project is underway.

City Commission to consider ARPA fund agreement for downtown drainage project [2023]

Engineers are wrapping up design now and they plan to put the construction out to bid this summer to start construction in earnest after July 4 through the fall.

The construction contract will go before the commission for consideration.

Jesse Patton, city engineer, said that all businesses will maintain pedestrian access and they plan to close a half block at a time, including the intersection, to allow for the most vehicle access as possible during construction.

Central Avenue will likely close from 2nd to 4th Street in the fall for paving over one or two days to save time and money, Patton said.

Commissioner Joe McKenney said he understands the project needs to be done, but road closures can be “the kiss of death” for small businesses.

He asked the engineers to keep small businesses in mind and get the project done as quickly as possible.

The downtown drainage improvement project is aimed at addressing problematic flooding that has occurred during high intensity rainfall events in recent years.

The most significant flooding event was in August 2016, when about one to three inches of rain fell in about an hour.

City receives $8.4 million in state ARPA funds [2023]

The city public works department used the study to develop the central drainage project which includes the area:

• along 3rd Street South and extends from 4th Avenue South to 2nd Avenue South;
• along 3rd Avenue South from 3rd Street South to 4th Street South; and
• along 2nd Avenue South from 3rd Street South to 5th Street South.

The project includes adding storm drain inlets, increasing underground pipe capacity, and better conveying storm water to the Missouri River.

The estimated budget for the project was $8.5 million in multiple staff documents from 2023.

In May 2023, commissioners approved a state grant agreement for the project.

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The city was allocated $3,729,200 in grant funds from the Montana Department of Natural Resources and Conservation through the competitive grant and minimum allocation grant programs of the American Rescue Plan Act through the state.

The city is using those funds toward the downtown drainage improvement project.

Public Works staff identified ARPA dollars as a potential funding source for the project.

The state was allocated about $2 billion in ARPA funds and the Montana Legislature put $582 million to local infrastructure programs including water and sewer projects, according to the staff report, of which $249 million was allocated to a competitive grant program for water and sewer infrastructure improvements.

There were two rounds of competition and the city’s downtown drainage project was one of four applications submitted for the second round of applications, according to the city.

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The downtown drainage project was ranked 20th of 174 applications and was awarded $1,864,600 through the competitive grant program, which requires a dollar for dollar match, according to the city.

The state also established a $150 million minimum allocation grant program that allocated pre-set calculated balances of ARPA funds to municipalities and the city was allocated $8,505,069.

City staff chose to use a portion of those funds to match the competitive grant, which commissioners approved in September 2022.

The city is planning to use a total of $3,729,200 in ARPA funds for the project as well as $2.5 million in downtown tax increment financing funds.

The city will fund $6,229,200 million of the estimated $8.5 million total costs before using utility fee revenues from city residents, staff said in 2023.

The project was selected and prioritized in the city public works’ capital improvement program, and was included in the 2023 budget of the storm drain utility enterprise fund.