Following National Park Service approval and an environmental analysis, Glacier National Park officials will move forward with modifications and improvements to the existing Quartz Creek fish barrier to try and suppress lake trout and other non-native fish from getting into Quartz Lake, the park announced Monday.
Located in the North Fork of the Flathead River drainage and the park’s North Fork District, Quartz Lake is believed to be one of the last remaining strongholds for bull trout in park waters west of the Continental Divide. The lake was believed to be the largest on the west side of the park accessible to lake trout but not yet colonized by them. However, lake trout were detected in 2005, threatening the long-term persistence of the Quartz Lake bull trout fishery.
A fish passage barrier was designed to protect the drainage from lake trout and other non-native species such as rainbow trout, brook trout and Yellowstone cutthroat trout. The barrier is roughly 100 yards below Middle Quartz Lake. The completion of the barrier was suspended until options to control lake trout could be reviewed.
An environmental assessment was released in February and a decision was recently signed by the National Park Service Intermountain Regional Director to move forward on the project. Fifteen comment letters were received during the review period, according to park officials, and 14 letters expressed support for the project and one expressed disagreement based on the opinion that efforts would be better spent where lake trout are not already present.
The National Park Service has since collaborated with the U.S. Geological Survey and others in an ongoing experimental program to remove lake trout from Quartz Lake and suppress the population. Experimental suppression has so far been promising, with identification of lake trout spawning areas and annual removal of spawning lake trout.
Also, the environmental analysis and review process for both the Rose Creek Fish Barrier Removal and Bridge Replacement Project has been completed and both can move forward.
An abandoned weir, or dam, on lower Rose Creek just above the Rising Sun Campground on the east side of the park has completely blocked native fish passage for decades. Additionally, the long-term structural stability of the Rose Creek Bridge on the Going-to-the-Sun Road is threatened by sediment scouring on the downstream side of a concrete slab spanning the width of the stream beneath the bridge.
In accordance with the decision, the weir will be removed to restore fish passage along Rose Creek. The weir has not been in use since 1971. The concrete forming the weir will be removed until it is level with the streambed or no longer presents a barrier to fish. The park will also replace the Rose Creek Bridge with a new, approximately 85 foot-long, concrete girder, clear -span bridge (no footings, pilings, or piers in the stream channel). The appearance of the new bridge will be more compatible with the historic design characteristics of the Going-to-the-Sun Road, park officials said.
Both actions will restore access to historic spawning and rearing habitat for native fish and improve stream flow and sediment transport along lower Rose Creek.