Engineers working on a drainage fix for the Willows subdivision in south Kalispell are holding a meeting tonight to share details about the project and gather public comments on a preliminary engineering report.

“This meeting gives the public a chance to voice concerns about the project,” said Keith Haskins, Kalispell’s senior civil engineer. “And if it’s something we can feasibly incorporate, we’ll try to address that as part of the design.”

The Kalispell City Council wrestled with the Willows project last summer, eventually supporting the creation of a special improvement district that homeowners there requested to pay for stormwater drainage improvements.

Kalispell will issue 15-year bonds through the Montana State Revolving Fund to pay for the work. Willows homeowners then will pay extra property taxes to pay off the debt.

Council members pledged to pay for however much of the estimated $392,556 project it takes to keep those extra taxes limited to $20 a month — a contribution public works staffers estimated could amount to anywhere from $122,000 up to $210,000, depending on final project costs and borrowing terms.

Kalispell opted to pitch in because the Willows’ stormwater system was approved more than a decade ago with an inadequate detention pond and 12-inch discharge pipe that doesn’t meet city standards. 

Willow tree roots clogged the discharge pipe in 2011. That caused widespread flooding in the neighborhood and prompted residents to campaign for an upgraded system that would let them hand maintenance responsibilities over to the city.

The project corrects problems with the detention pond, stabilizing its banks and creating access for future city maintenance. It also installs 1,260 feet of 18-inch drainage pipe from the detention pond to the Stillwater River with an improved outfall.

Some homeowners and city officials questioned whether adjoining Leisure Heights and Muskrat Slough neighborhoods are contributing significant amounts of stormwater to the Willows’ system and if those areas should help pay for the project. 

But the biggest contributors are the Willows itself and a Flathead County-owned shop directly south of the neighborhood that contributes the majority of stormwater flows based on drainage modeling. 

“It’s a big impervious gravel area and there’s not a lot of grass for water to percolate in. So because of that and the close proximity, it is a big contributor,” Haskins said.

The Willows project is on track to go to bid in May, with work starting in July and taking 60 days or less to finish. For homeowners, the biggest impact from construction likely will be the installation of stormwater treatment devices in the neighborhood’s stormwater sewer system.

“They are very large and take a lot of room to install at the edge of the street,” Haskins said. “That could cause some traffic control issues, and possibly some access issues to homes for limited times.”

Reporter Tom Lotshaw may be reached at 758-4483 or by email at tlotshaw@dailyinterlake.com.