Lift station controls pace of growth

By JOHN STANG/The Daily Inter Lake

You can't actually see Kalispell's sewer lift station at the corner of U.S. 93 and Grandview Drive.

It's underground.

But you can see the bright green transformer shell on top, surrounded by a wood panel fence in a sunken hollow.

Heck, you'd easily miss the big transformer shell unless you were actually looking for it.

This spot, with its subterranean sewage lift station, controls how fast Kalispell's north side can grow " not today, but likely a few years from now.

This sewage lift station is a potential bottleneck for sewage to flow from northern Kalispell to the city's sewage treatment plant on the south side.

Only so much sewage can go through the lift station at a time.

That capacity is currently 460 gallons per minute, with the peak volume recorded so far of 416 gallons a minute. The city Public Works Department plans to enlarge that capacity to 860 gallons a minute in the spring for roughly $400,000.

So next year, the expanded sewer lift station ""which handles most of the sewage to the north ""should have a spare unused capacity of 444 gallons per minute.

Using the Public Works Department's formulas, that unused capacity of 444 gallons per minute translates to the ability to handle the sewage needs of an estimated 1,168 homes.

Long-range development plans for northern Kalispell greatly exceed that amount.

In fact, Grandview's lift station's capacity will be completely filled according to how fast current growth plans unfold.

The keys to this puzzle are the preliminary plats already approved for northern Kalispell, according to City Public Works Director Jim Hansz and Assistant City Engineer Paul Burnham.

Preliminary plats are essentially rough initial plans on how a development will be laid out, after the Kalispell City Council approves them.

A preliminary plat also needs approval from the Montana Department of Environmental Quality " which looks at a development's likely sewage volumes and the city's capacity to deal with them.

Right now, preliminary plats have been approved for the first phases of some multiple-phased northern Kalispell projects: Silverbrook Phase One, Starling Phase One, Bloomstone Phase One.

Preliminary plats also have been approved for all of West View Estates, Hilton Homewood Suites, Hutton Ranch Plaza, a new Montana Department of Natural Resources and Conservation building, and the Spring Prairie shopping area.

All of these preliminary plats would produce enough sewage equivalent to the output from 993 typical houses, according to city government calculations.

After all the buildings in those approved preliminary plats are built, the expanded Grandview lift station will be able to handle sewage from the equivalent of 175 extra homes.

This leaves loose ends such as:

? When the toilets of the future Glacier Town Center are analyzed, what will be their equal in numbers of homes? Restaurants produce a significant amount of sewage, so the number of restaurants in the shopping center will be a factor in those calculations, Hansz said.

? The 911 center expected to be built in northwest Kalispell needs to be accounted for.

? Two other future northside housing subdivisions " Valley Ranch and Flathead Village Greens along U.S. 93 North " each likely would build significantly more than the equivalent of 175 homes. Neither has yet received preliminary plat approval.

? Any second and subsequent phases of the current north-side subdivisions likely will exceed the equivalent of 175 homes.

An unknown factor is how fast construction will proceed in northern Kalispell.

From 2004 through 2007, the city has issued building permits for an average of 382 housing units a year - counting single-family houses, halves of duplexes and individual apartments in buildings.

However, City Planning Director Tom Jentz estimated that 2008's total could be roughly 200, reflecting the current economic downturn.

Consequently, it could take years before northern Kalispell seriously approaches building the equivalent of 1,168 new homes.

So what happens after it does?

"The Grandview lift station is only a bottleneck. … if you force everything through it," Hansz said.

So when northern Kalispell threatens to exceed the lift station's 860-gallon-per-minute capacity, a new sewer line with its own lift stations likely would be built through western Kalispell to reach the sewage treatment plant. A possible route would be the U.S. 93 Bypass corridor, Hansz said.

At that point, north-side developers can either bunch together to build a new west-side sewer line and lift stations " or one developer can do so and charge the others to hook up to it.

Either choice goes into uncharted territory on how developers would work with each other and how the city's sewer impact fees would be applied.

Hansz and Burnham estimated that the potential west-side main sewer line and lift stations would run 5.5 to 6 miles - costing at least $4.5 million, a figure expected to increase as more time passes.

Meanwhile, three major southern Kalispell projects " Willow Creek, Siderius Commons and a Gardner family owned venture - do not have the same overloading potential, Hansz said.

That because similar potential lift-station bottlenecks don't exist in southern Kalispell, where the sewage treatment plant is located.

The sewage plant is processing roughly 3 million gallons a day, and has an official capacity of 3.1 million gallons a day.

The plant's expansion is expected to finish in 2009, boosting its capacity to 5.4 million gallons a day, with groundwork laid for an additional potential expansion to 7.5 million gallons a day if needed.

A rule of thumb is that 4,000 homes equal 1 million gallons of needed treatment capacity.

Consequently, Kalispell would need the equivalent of 8,000 new homes to break the 5-million-gallon-a-day mark.

The city has roughly 7,000 homes earmarked on 20-year-long development plans, which could stall or disappear in future phases.

Reporter John Stang may be reached at 758-4429 or by e-mail at jstang@dailyinterlake.com