DEQ Issues Draft Environmental Assessment for Proposed Drinking Water and Wastewater Facilities for the Quarry Phase II Subdivision Near Big Sky

The Department of Environmental Quality (DEQ) is requesting public review and comment on a draft Environmental Assessment (EA) regarding proposed drinking water and wastewater facilities near Big Sky in Gallatin County, Montana.   

 

Big Sky Rock, LLC, applied to DEQ for a Certificate of Subdivision Approval (COSA) to install infrastructure associated with the proposed “Quarry Phase II” development. Under state law, a COSA is required for the drinking water, storm water, and wastewater facilities that would service the proposed development. DEQ also reviews the public water, storm water, and subsurface wastewater treatment systems for nondegradation and cumulative impacts to groundwater and surface water. The proposed subdivision was approved by Gallatin County Platting and Planning on April 16, 2024. 

 

In its application, Big Sky Rock, LLC, proposed that water services would be provided by connection to the existing Lazy J Utility Association facilities. Water will be provided through water main extensions and service connections to the new lots. Each of the proposed four lots would have its own wastewater treatment system provided by a Level II wastewater treatment facility and drainfield. Level II treatment systems can significantly reduce the nitrogen from wastewater prior to treatment by the soils.  

 

Stormwater retention and treatment would be provided by one on-site retention pond, swales, roadside gutters, storm sewers and manholes. Stormwater for the lots would be treated, retained and infiltrated by on-site storm water ponds proposed by the developer in Phase II or in oversized ponds built during Phase I that was previously reviewed and approved by the Department.  

 

DEQ prepared the draft EA in compliance with the Montana Environmental Policy Act to analyze potential impacts of the proposed facilities on the human environment. The scope of the draft EA is limited to DEQ’s review of proposed water, wastewater, and storm water facilities to assure that the design of these systems complies with Montana law. The draft EA examines the proposed action and alternatives to the proposed action and discloses potential impacts that may result. In the draft EA, DEQ found there are no anticipated significant impacts to the surrounding environment from the proposed drinking water, storm water and wastewater facilities.  

 

DEQ is now accepting comments on the draft EA, after which DEQ will review comments, determine the need for additional environmental review and make a final decision on the application. The deadline for this comment period has been extended until Jan. 10, 2025. To view the draft EA and learn how to submit a comment visit: https://deq.mt.gov/News/publiccomment-folder/Quarry-Draft-EA