SUPPLEMENTARY INFORMATION:

The Final EIS analyzes five alternatives to address the rehabilitation of the wastewater treatment system that currently serves the west side of Glacier National Park. The service area for the existing wastewater treatment plant includes park headquarters and residences, campgrounds, Lake McDonald Lodge, and concession businesses and employee housing. The existing wastewater treatment plant is no longer meeting its original treatment objective or operating at design capacity. The preferred alternative (alternative 3) is to construct an advanced wastewater treatment plant with an exfiltration gallery land discharge site. This alternative would provide the greatest level of treatment and the highest water quality of the alternatives considered. Minimal new site disturbance would be necessary to implement the preferred alternative. Based on public concerns, the discharge method for the treated effluent was selected that best protected the environment. Alternative 1A includes construction of an additional storage lagoon and anew spray field to discharge treated effluent. This would require clearing 6.5 hectares of undisturbed land and the existing spray field, located in the floodplain, would continue to be used. Alternative 1B includes construction of two new storage lagoons and an additional aerated lagoon (3.6 hectares). The existing spray field would continue to be used. Alternative 2 includes construction of an advanced wastewater treatment plant and a series of three rapid infiltration basins (3.6 hectares) to discharge treated effluent to the groundwater. The existing spray field would no longer be used. The No Action alternative (alternative 4) would continue operation of the existing wastewater treatment system and spray field. Occasional raw sewage spills are possible when storage capacity is exceeded and the spray field cannot be operated because of wet conditions.

The Final EIS in particular evaluates the environmental consequences of the preferred alternative and the other alternatives on wildlife, vegetation, threatened and endangered species, water quality and park and concession operations.