The Big Creek tributary on the North Fork of the Flathead River has been restored and removed from a list of impaired waterways, the Hungry Horse Ranger District and Montana Department of Environmental Quality announced last week.
Federal officials said Big Creek is the first in the state to successfully undergo water quality restoration after years of sediment and soil erosion significantly impaired the stream.
“The delisting of Big Creek for sediment is a significant accomplishment that demonstrates our commitment to watershed improvement,” Hungry Horse District Ranger Jimmy DeHerrera said in a statement.
Big Creek is connected to the Flathead River system in British Columbia and Montana and provides critical habitat for bull trout, a species listed as threatened under the federal Endangered Species Act. Bull trout lay their eggs in a gravel substrate and the survival of early life stages of this fish is reduced when the spaces between gravels become filled with fine sediment.
Historic road building and timber harvesting activities in the Big Creek watershed led to accelerated soil erosion and a substantial increase in the amount of fine sediment delivered to Big Creek. Frequent monitoring by Montana Fish, Wildlife, and Parks revealed degraded fish habitat due to an increases in the amount of sand and silt in bull trout spawning habitat. It was officially listed as impaired in 1996.
Spurred by this listing, the Flathead National Forest collaborated with DEQ to complete a watershed restoration plan in 2003. The plan prescribed a variety of best management practices for reducing sediment loads from controllable sources in the watershed.
Recent monitoring data shows that sediment and stream conditions in Big Creek are now similar to conditions in streams with minimal human impacts. Most notably, there has been a substantial decrease in the amount of sand and silt in bull trout spawning habitat. Based on this data, DEQ removed sediment as a cause of impairment to Big Creek on the state’s list of impaired waters in 2012. EPA approved this action in April 2012.
“The Hungry Horse Ranger District has worked very hard to improve water quality in Big Creek through road decommissioning, road improvements, culvert removals and upgrades, and revegetation,” DeHerrera said. “In addition, this work provides an excellent model for other restoration efforts in the State aimed at addressing impaired waters.”