GALLATIN COUNTY, Mont. — The Department of Environmental Quality released a final Environmental Assessment regarding proposed drinking water, stormwater and wastewater facilities near Big Sky.

Officials say the proposed facilities meet the requirements of the Montana Environmental Policy Act and there are no anticipated impacts to the surrounding environment.

This comes after Gallatin County officials approved the proposal to install drinking water and wastewater facilities associated with the Quarry Phase II development.

In its application real estate development company Big Sky Rock, LLC proposed the water services be connected to the existing Lazy J Utility Association facilities.

It also proposed that water be provided through water main extensions and service connections to new lots.

Officials also say each of the four lots would have individual wastewater treatment systems through Level 2 wastewater facilities and drainfields.

The proposal adds stormwater retention and treatment would be provided by on-site retention ponds, swales, roadside gutters, storm sewers and manholes. It also says stormwater would be treated, retained and infiltrated by on-site storm water ponds.

The DEQ sent out the following about the environmental assessment:

The Department of Environmental Quality (DEQ) has published a final Environmental Assessment (EA) regarding proposed drinking water, stormwater and wastewater facilities near Big Sky in Gallatin County, Montana.

DEQ appreciates the time and consideration that went into the comments provided on the draft EA. DEQ prepared the EA in compliance with the Montana Environmental Policy Act and found there are no anticipated significant impacts to the surrounding environment from the proposed drinking water and wastewater facilities. The final EA includes DEQ’s responses to substantive comments received during the public comment period.

The proposed Residential Quarry Phase II subdivision was approved by Gallatin County Platting and Planning on April 16, 2024.Big Sky Rock, LLC, applied to DEQ for a Certificate of Subdivision Approval (COSA) to install drinking water and wastewater facilities 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.

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 2 wastewater treatment facility and drainfield. Level 2 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.

The final Environmental Assessment can be found on DEQ’s website.