After pausing new Big Sky subdivision approval, DEQ reviews plant capacity
Agency approves water and sewer district deviation request, says no building moratorium
By Gabrielle Gasser and Brandon Walker
BIG SKY – In June, the Montana Department of Environmental Quality temporarily froze approval of new subdivisions in Big Sky citing capacity concerns at the Big Sky County Water and Sewer District’s wastewater treatment plant. DEQ is currently reviewing documentation from the district to prove that the plant has capacity for new subdivisions, according to DEQ officials.
The approval freeze should not be equated to a moratorium, said water and sewer district General Manager Ron Edwards, adding that when the approval process was paused, there was concern that new Big Sky developments would be shut down.
“That was never the case,” Edwards said.
DEQ officials told EBS that an official building moratorium has not been issued. In 1993, DEQ imposed a moratorium on any new wastewater connections in Big Sky and lifted it in 1996 after the water and sewer district upgraded its irrigation and wastewater systems.
While DEQ is still reviewing capacity documentation, Edwards announced at an Oct. 20 water and sewer district board meeting that the agency recently approved the district’s deviation request. The approval means that the district can continue utilizing its Single Family Equivalent approach when allocating wastewater flow for commercial and residential establishments, a variation from traditional design requirements, DEQ officials said.
“DEQ requirements for how wastewater capacity is allocated per living and commercial unit were not being met in the capacity letters associated with COSA applications that DEQ was receiving from the district,” said DEQ Environmental Engineer Ashley Kroon in a statement provided to EBS. COSAs refer to Certificate of Subdivision Approvals.
Once the water and sewer district became aware that DEQ wanted additional documentation demonstrating wastewater treatment plant capacity, the parties held a series of online meetings and spent a substantial allotment of time reviewing old data and permits.
“They wanted information on our side just to validate how much capacity is in the treatment plant,” Edwards said. “Any time you have a new subdivision you need a capacity letter from the entity that would be serving you. The DEQ wanted information showing that we have plant capacity before they process any new subdivisions.”
Kroon, with DEQ, said the agency requires proof that a system has capacity to serve a project proposing any connection to the public system.
“The discrepancy between the district’s use of SFEs versus DEQ design requirements for calculating wastewater capacity resulted in confusion regarding the actual volume of capacity that had already been allocated through capacity letters associated with COSA applications,” Kroon said.
Currently, the wastewater treatment plant in Big Sky has the capacity to handle 650,000 gallons per day. Of that capacity, 150,000 gallons per day is available to add new subdivisions, according to Edwards.
Terry Campbell, environmental engineer for DEQ, said the agency is “… still reviewing the data that [Edwards] had provided to us to determine if they feel that’s adequate.” DEQ officials said they intend to finish reviewing the documentation the week of Oct. 26.
Any submitted COSAs that were paused when DEQ halted its review process will not be subject to re-submission as a result of the freeze, Kroon said.
Once the upgrade to the wastewater treatment plant is complete—currently anticipated for the summer of 2022—the plant’s total capacity will double to 1.3 million gallons per day.