City may help out Willows project

The Kalispell City Council on Monday seemed to agree the city should pay for at least part of an estimated $392,000 project to improve stormwater drainage in the Willows. 

The city contribution could be as much as a third, covering an estimated $129,000 to install an 18-inch pipe that would reroute stormwater from other developments around the south Kalispell neighborhood and into the Stillwater River.

“The Willows system was approved. Period ... That’s a problem the city is going to have to face,” council member Bob Hafferman said.

Hafferman suggested the city continue to look for grant money to help, and that money from the city’s stormwater assessments and stormwater impact fees should be used to pay for that part of the project.

After flooding in the Willows in spring 2010, homeowners asked the city to form a special improvement district to pay for upgrades to the neighborhood’s stormwater drainage system.

A resolution to form that district was tabled one week ago. That was done at the request of homeowners concerned about the project’s cost and whether other neighborhoods or even the city and county should help pay.

If the district ultimately is approved, Kalispell would issue 20-year bonds to upgrade the stormwater system.

Homeowners then would pay extra property taxes to pay off the debt. And the city would agree to assume ownership and maintenance of the system if it’s brought up to code.

FLOODING IN the Willows in 2010 was caused by a root from a willow tree in a homeowner’s yard. 

The root clogged a 12-inch discharge pipe that runs from the neighborhood’s stormwater detention pond. 

That caused the pond to fill up with more than 20 feet of water that backed up into streets and crawl spaces.

“Once the willow root was removed, the water dissipated in about a day,” Public Works Director Susie Turner said.

BUT OTHER stormwater drainage problems remain.

The neighborhood’s detention pond is eroding and it was built in a way that makes it inaccessible to maintenance equipment. 

Its 12-inch discharge pipe is too small. And an outfall line that runs to the Stillwater River is clogged with sediment and also inaccessible.

The system does not meet city standards and a large storm event could cause it to backup again, Turner said.

COMPOUNDING THE problem is the Willows’ location at the end of a natural drainage swale.

Leisure Heights, a neighborhood to the north that meets city standards, discharges its stormwater farther up the swale. 

That sends its stormwater — which is discharged at a rate that does not exceed pre-development flows — into the Willows system.

Water from Muskrat Slough to the west  can work its way into the swale and the Willows. 

And a county-owned property to the south also discharges stormwater into the Willows system.

WHEN THE Willows was being developed through the county and the city in the late 1990s, city officials insisted on a 15-inch discharge pipe from its detention pond. 

The developer, now out of business, responded with a request to install a 12-inch pipe. 

And city officials today can’t find any records to determine how that request was handled.

“But that 12-inch pipe is what is currently there and the contractor installed that,” Turner told the council Monday.

A homeowners association was supposed to form to maintain the stormwater system but that never happened.

THE PROPOSED work would build a new detention pond outlet, install a new 18-inch overflow pipe parallel to the existing 12-inch discharge pipe, stabilize the detention pond’s banks, install a second treatment cell and construct a maintenance access ramp.

The project also would install a new 18-inch bypass line to collect flows from Leisure Heights and Muskrat Slough and route them around the Willows and down to the river. 

Several council members took issue with putting that part on the backs of homeowners in the Willows.

“We’re having the Willows pay for new infrastructure to bypass everyone else’s [stormwater] around there,” councilman Phil Guiffrida III said. “That’s where I’m hung up.”

But the flows coming down from Leisure Heights do not exceed pre-development flows. 

And developments that discharge into Muskrat Slough were already built before the Willows, Turner said.

The Willows also would use that 18-inch bypass pipe. 

It would be an “overflow pipe” to take on heavier flows its detention pond and insufficient 12-inch discharge pipe can’t handle, and let the neighborhood meet city standards.

But the same concern is shared by some homeowners in the Willows.

“Absolutely, the part I have a hard time stomaching is the bypass of upstream flows,” Mark Armstrong told the council.

Pulling out the cost for the 18-inch bypass line would reduce monthly payments from $30 to about $20 and make it a more palatable project for homeowners in the Willows, Armstrong said.

“If we could mitigate the cost a bit, that would make a lot of people happy,” Armstrong said, adding that residents of the Willows pay Kalispell’s stormwater assessments just like everyone else.

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