NorthWestern Energy develops and follows an annual Integrated Vegetation Management Plan (IVMP) for managing vegetation growth in our electric rights of way (ROWs). The primary objective of our plan is to reduce the likelihood of tree-caused outages on our electric system and to control noxious weeds. However, our IVMP also encourages the growth of native grasses and shrubs providing vegetation and habitat preferred by many species of wildlife.
The company has 7,200 miles of electric transmission ROW and about 15,000 miles of electric distribution ROW in Montana alone. These corridors vary from 10 to 75 feet on each side of the line depending on the voltage. Annually our group of skilled arborists and vegetation management technicians physically inspect our electric transmission lines and identify then address potential issues. We spend more than $8 million annually on transmission and distribution ROW maintenance.
In addition to providing excellent habitat for wildlife like elk, deer, bears, small mammals and many songbirds, our ROWs play a strategic role in controlling wildland fires. Fire fighters often view our electric corridors as firebreaks as well as critical transportation routes for crews.
Developing a successful ROW management plan involves many groups. We work with representatives from the Forest Service, Bureau of Land Management, Montana Department of Natural Resources and Conservation along with individuals from city and county governments and tree or forestry agencies.