Chippy Creek Project
The Chippy Creek stream crossing on the Lanes Creek Cutoff Road was identified as a high priority for restoration by the U.S. Forest Service during their Upper Blackfoot Watershed Analysis. An undersized crossing was causing channel instability and loss of aquatic habitat. Nearly 700–1,000 ft of channel has been lost near the crossing. Caribou County identified this as the highest priority for replacement in the upper Blackfoot drainage.
The Chippy Creek stream crossing structure replacement portion of this project was completed during the week of November 7, 2018. We replaced the existing undersized crossing that consisted of two squash pipes (each was 36 ft long by 3 ½ ft high by 5 ½ ft wide) with a concrete box structure (6 ft high by 15 ft span). We constructed a natural channel within the box and placed cobble-gravel substrate approximately one foot deep to form the channel bed.
We also elevated and stabilized approximately 300 ft of channel downstream from the crossing when we installed the new structure. The remaining ~5,000 feet of stream channel work will be completed in 2019, including a total of 2,210 ft upstream from the structure and 3,118 ft downstream from the structure.
The cumulative benefits of the project include (1) improved fish passage, (2) reduced erosion, (3) flood mitigation and road protection, and (4) restored stream function and stability due to increased channel length and floodplain reconnection. The channel and floodplain elements also restore streamside vegetation and adjacent wetland complexes that were lost when the stream down-cut.