Kalispell City Council on Monday will review updated plans for future infrastructure improvements to the municipality’s water and wastewater systems.  

The documents consider current challenges facing the city’s essential utilities and will serve as long-range planning documents to guide infrastructure improvements that support future growth, according to a memo from City Manager Jarod Nygren.  

Council meets at 7 p.m., June 22 in City Hall, 201 First Ave. E.  

Kalispell has grown and experienced shifts in development patterns since its water, wastewater and advanced wastewater treatment plans were last adjusted in 2018 and 2019, according to the memo.  

The updated water facility plan groups future capital projects into near- , mid- and long-term categories. By 2044 — the city’s near-term planning horizon — water demand is expected to rise significantly as the population grows to an estimated 51,000.  

The average water demand is expected to rise from 4 million gallons per day to 6 million gallons by 2044.  

To meet the level of service, Kalispell’s upper pressure — which constitutes the water system north of Two Mile Drive — will eventually require 4.2 million gallons per day in additional well supply. The city also plans to install additional elevated water storage between 2040 and 2045.  

A shorter-term project includes the ongoing effort to replace the transmission main beneath Woodland Avenue with larger pipes and connect it with two forthcoming drinking water wells being drilled at Dry Bridge Park.  

Some projects slated for 2027 include replacing a water main between Conway Drive and Ryder Road, along with repairing a water main on Second Avenue West.  

Despite the anticipated increase in demand, individual water usage has dropped from 190 gallons per person per day in 2017 to 26 gallons per person per day in 2024.  

The plan attributes the change to infrastructure upgrades, high-efficiency plumbing and water conservation efforts. 

While nearly 160 miles of Kalispell’s water mains are deemed in good condition, just over 8 miles warrant upgrades in the near-term. Most of the projects are concentrated in residential neighborhoods around downtown, likely due to the presence of older cast iron pipes, according to city documents. 

The plan calls for creating a new pressure zone to improve service to the growing west side. The West Pressure Zone would eventually require a 4-million-gallon elevated storage tank, planned as a 2029 capital project. However, significant growth is not expected there for some time.  

THE WASTEWATER Collection System Facility Plan Update outlines future upgrades to the miles of pipes and lift stations that move sewage to the municipal treatment plant neighboring Kalispell City Airport.   

About 26% of what flows through the city’s wastewater system is inflow and infiltration, which is stormwater or groundwater that seeps into the city’s sewer system, according to city documents.  

The plan recommends launching a separate study slated for 2028 that would examine the effects that the seepage has on the city’s wastewater collection system. 

Projects planned in the coming years include increasing the size of sections of gravity main to handle future wastewater flows.  

Increasing capacity in the Westside Interceptor is especially important as Kalispell grows. An interceptor is a large underground pipe that collects sewage from smaller pipes before transporting it to a treatment plant. The $31 million project is slated for 2033. 

THE ADVANCED Wastewater Treatment Plant plan laid out three scenarios for capital improvements, depending on how strict future water quality standards are for a portion of Ashley Creek, where the city discharges its treated wastewater.  

Montana is shifting toward nutrient standards that emphasize site-specific assessments over strict numeric limits, according to the plan.  

Reporter Jack Underhill can be reached at 406-758-4407 or [email protected]. If you value local journalism, pledge your support at dailyinterlake.com/support.