The Rainy River - Black River watershed, covering 335,184 acres, or 524 square miles, flows into the Rainy River, a border water between Minnesota and Ontario, Canada. This portion of the Rainy River flows west from International Falls up to the East Rapid River watershed. The watershed’s population is primarily in International Falls (7,638 residents in 2000, which fell to 5,839 in 2009). This watershed is entirely in Koochiching County.
This watershed’s acreage is mainly in the Black and West Fork of the Black River sub-watersheds which are in the ecological sub-region of the Agassiz Lowlands. The watershed also features a narrow band of land that runs due east along the Rainy River to International Falls. It is interrupted where the Big and Little Fork Rivers enter the Rainy River. This narrow corridor to International Falls is in the Little Fork-Vermillion Uplands ecological sub-region. The majority of this very flat watershed (224,481 acres) is wetlands. The only lakes are very small and cover 187.6 total acres. A substantial portion of this area is state forest lands consisting largely of black spruce and tamarack. There are farms near the Rainy River in the main Black River and West Black River portions. The major land use is logging; one of the main employers is a large paper mill in International Falls.
What's being done
The basin plan for the Rainy River, which included this watershed, was published in 2004 by the Minnesota Pollution Control Agency in partnership with local, county, and other state agencies. Significant efforts have been made to collaborate with Canadian resource agencies and the International Joint Commission to manage both the U.S. and Canadian portions of the basin: Rainy River Basin Plan
Monitoring and assessment
Intensive watershed monitoring on this watershed began in 2017.