Vieau Associates/GZA was commissioned to complete a Phase I ESA to support the transfer of 18,800 acres of federally owned native grasslands and forested low-rolling mountains in Montana to federal trust ownership for the Confederated Salish and Kootenai Tribes. At the center of the Flathead Indian Reservation, the National Bison Range had been managed as a National Wildlife Refuge by the U.S. Fish & Wildlife Service since 1908 and is home to the largest free-range herd of plains bison in the world.

The history of the property presented several possible areas of concern, including the integrity and construction of current and historical dwellings, a museum, barns, maintenance shops, corrals and a slaughterhouse; The quality of water wells into aquifers hundreds of feet deep and numerous shallower artesian wells which provided drinking water for employees, domestic animals, and the bison herd; and the historical use of pesticides and possible improper disposal Septic systems, heavy equipment maintenance and adjoining commercial operations needed to be considered in connection with the quality of soil, groundwater and surface water resources.


This large-acreage assessment achieved exacting conformance to the requirements of the EPA All Appropriate Inquiry Rule (40 CFR Part 312) by applying procedures set forth in ASTM Standard Practice E2247: Phase I Environmental Site Assessment Process for Forestland or Rural Property. The Vieau team researched over 100 years of occupancy using records from multiple sources, historical aerial photos, maps, and the knowledge of Fish & Wildlife Service personnel before conducting several days of all-terrain excursions to adequately ground-truth the nearly 30 square miles within the wildlife refuge. This research found a range of unexpected environmental issues not generally expected in a remote, non-industrialized and sparsely populated wilderness area.


The Phase I assessment effectively addressed risks associated with arsenic-laced pesticide disposals in the 1950s, numerous underground storage tanks including those pre-dating regulations, and more recent matters of hazardous waste and wastewater management.