Final Report - Flathead County, Montana

CAPACITY TO SERVE AREAS OUTSIDE OF EXISTING SERVICE AREA:
Discussions with Lorin Lowry have focused on the willingness of the City and the
capacity of the City’s wastewater system to serve existing development with septic
systems in relative close proximity to the public sewer system. In general, Lorin was
agreeable to the idea of removing septic systems and putting them on City sewer, but
he said individuals would have to obtain City approval first. Additionally, he said it is
City policy that these individuals then should hook up to City water and that City
standards should also apply to roads, sidewalks, etc. To obtain City sewer service,
these properties would have to annex into the City or, at a minimum, sign a statement
waiving their right to protest annexation.
Additional discussions were held concerning the capacities of the City’s sewer
conveyance system and treatment facility. As previously mentioned, HDR completed a
Wastewater Utility Plan in 2006 and, for the most part, this Utility Plan addressed
Columbia Falls’ Potential Wastewater Utility Service Area with the purpose of
determining the wastewater service population in the year 2025 and sizing the treatment
plant accordingly to handle these flows.
HDR’s report did not provide any modeling of the existing sewage conveyance
system and lift stations to determine component capacities. HDR did make several
recommendations on the lift stations but only based them on the age of equipment or
operational problems with the stations, as reported to them by City personnel. The City
has been completing some of these recommendations in-house as their annual budget
allows. To date they have replaced both pumps at Lift Station #2 and one pump each at
Lift Station Nos. 4 & 6. Pumps that have been replaced were replaced with the same
pump model and capacity with no upsizing. Additionally, it was stated that any new
sewer flows to Lift Station #2 would require an upgrade in wet well size.
Although flows have not been modeled for the sewer conveyance system, it is
the City’s opinion that some of the sewer lines and lift stations may be approaching
capacity, however, they have not had any problems with sewer surcharges.
Accordingly, future extensions of sewer mains will require sewer flow modeling to
determine if the capacity exists to convey additional sewage to the treatment facility.
Parts of the City’s wastewater treatment facility have been upgraded to year
2025 projected flows as part of the Phase 1 improvements discussed earlier. Phase 2
improvements were to take place in 2015, in part due to higher growth rates that were
occurring from 2000 – 2006 when the report was written. The growth rate has slowed
since this time period and, according to Lorin, there is now no big push to complete
Phase 2 improvements. Taking on new users with existing septic systems may be an
attractive alternative to the City to help make up for revenue lost due to stagnant growth
and to help pay off the bonds used to finance Phase 1 improvements.
Sewage Treatment in the Flathead Basin 21