By Bay Stephens EBS STAFF WRITER
BIG SKY – The Big Sky Water and Sewer
District board agreed in their Feb. 19 meeting to have a hydrogeologic study of
the meadow aquifer conducted, an initial step toward an innovative and
sustainable effluent disposal option commonly practiced in the southwest
states.
The board agreed to draft a request for
proposal for a firm to conduct the comprehensive study on the aquifer, which lies
beneath Big Sky Town Center, the Big Sky Golf Course and Meadow Village Center,
and supplies part of Big Sky’s drinking water.
The study, according to engineer Scott
Buecker of Bozeman-based Advanced Engineering and Environmental Services, would
reveal more about the anatomy of the aquifer, and how water and nutrients move
through it. It would also be a key step for the district to determine whether
recycling highly treated effluent via the meadow aquifer, a method called
indirect potable reuse, is possible in the future.
Implementing such an effluent disposal
option would only be possible after phases one and two of the BSWSD wastewater
treatment plant upgrade were completed, raising the district’s effluent to an
extremely high quality. Phase one is now under design by AE2S while phase two
is not currently necessary for the district to meet its effluent-disposal needs,
according Buecker.
Indirect potable reuse involves injecting
this treated effluent back into the groundwater, recharging the aquifer so wells
in that aquifer draw the same water for treatment and drinking. The method
enables water to be used multiple times and has become more common practice in
arid southwest states, Buecker said.
Although it’s common elsewhere, direct
potable reuse has never been done in Montana and requires an aquifer that
supports the process.
The hydrogeologic study would reveal
whether the meadow aquifer could support indirect potable reuse. If so, the
district would then have to work with the state’s Department of Environmental
Quality to develop regulations for the unprecedented effluent reuse option.
“It’s not a slam dunk,” Buecker said,
explaining that the meadow aquifer is already known to be complex, potentially
presenting challenges to effluent injection and reuse.
Despite the uncertainty, other
stakeholders are excited about the process, including Upper Missouri
Waterkeeper Executive Director Guy Alszentser.
“This is probably the happiest I’ve
been,” Alszentser told the board on Feb. 19. “I’m really glad to see the board
taking the initiative to investigate thoroughly another means of disposal that
is in line with what [the conservation community] thinks is the highest and
best use of water. I think it speaks to the integrity of the process here.”
Performing a comprehensive study of the
aquifer that allows the district to know definitively how water moves could
cost $300,000, Buecker estimated. In a phone interview after the meeting,
Buecker added that such a study could take around two years.
Although the need to supply more water to
Mountain Village presses as Big Sky grows, the board also voted to wait to
develop treatment options for two wells at the base of Lone Mountain until
further well exploration takes place this spring.
The two wells were drilled in the 1990s by
Lone Mountain Springs, the Boyne Resorts-owned-and-operated utility for
Mountain Village before the district took over. Although initially promising
sufficient outputs, recent tests revealed the wells could produce only paltry
amounts over sustained periods compared to what was expected, and could require
expensive treatment and filtration.
“We need to find more water one way or the other,” BSWSD Water Superintendent Jim Muscat told the board. “We can’t expand on the mountain without more water because we thought we had [enough]. We don’t. We have a water deficit on the mountain, and we have to … find greater [water] supplies.”
It’s a very real possibility the well
exploration unearths no better alternatives, Muscat added in an email to EBS,
but said it’s worth a shot.
