City Commissioners approved a $12,000 contract change for Great West Engineering for preliminary engineering and planning for a new stormwater pond in northeast Great Falls during their June 2 meeting.

Commissioners approved the initial $77,062 agreement in September 2025 to “conduct a study, findings and recommendations in a report that identifies and evaluates rerouting the 3rd Avenue South trunkline to discharge into a new pond location that provides additional storage, reduces peak flows in the main interceptor, eliminates the need for costly downstream pipe upsizing, and creates capacity for development. This project was prioritized based on the recent stormwater
master plan completed by Great West.”

The amendment expands the project scope to include three additional pond and storm drain alternatives, each of which builds onto the existing pond site for increased capacity, landowner coordination for potential expansion, refined cost, hydrologic, and constructability analysis to identify the most feasible long-term regional solution, according to the staff report.

The 2025 Stormwater Master Plan, adopted by commissioners in October, prioritized this project to reduce surface flooding and expand storm system capacity for future development. The plan identified 5200 2nd Ave. N. and adjacent properties as the preferred location for a long-term regional facility.

In May 2025, commissioners approved the purchase of a 3.23 acre parcel for $374,000 for a future regional stormwater pond. The property is within the county with commercial zoning, functioning as an existing detention pond on a low-lying area, according to city staff.

The Montana Department of Transportation owns and maintains an existing stormwater lift station that pumps water out of this pond into the city’s stormwater system near Loy Elementary.

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City staff recommended the purchase since “a future improved city-owned pond in this location would help alleviate existing storm pipe capacity issues in this area,” according to the May 2025 staff report.

City stormwater is already routed around this pond and surrounding county parcels by a network of storm mains.

“Modeling associated with the upcoming stormwater master plan shows significant flooding and full pipe capacity issues in these nearby storm mains, especially on 3rd Avenue South. Flows from these areas could be rerouted to this pond via new storm mains and alleviate the capacity issues. Another benefit is the detention of stormwater, reducing the impact to pipe networks,” according to city staff.

The property could support an estimated pond volume of 500,000 cubic feet, according to staff, and the upstream basin that could drain to the pond includes undeveloped properties between 57th Street South and Malmstrom Air Force Base and between Loy and the east side Walmart, according to staff.

The city may be eligible to recoup some of the costs of the stormwater improvements on the property based on a development’s proportional use, according to staff, and the property could be used for a future sanitary sewer station lift since it’s in the natural low spot of the area.