A series of flood events, including a flow of 18,900 cfs in 1999, caused bank erosion and channel migration to encroach into productive farmlands and damage the riparian corridor along Fountain Creek. State-of-the-art toe wood structures and large riprap bank protection methods were used to stabilize and enhance two miles of Fountain Creek on the Barr Farm. Application of geomorphic design principles, 1D and 2D hydraulic modeling and sediment transport modeling for Phase 1 (4,900 ft) and Phase 2 (6,100) guided the realignment of the creek’s main channel to create a stable plan form and the reshaping of the channel cross section. Channel parameters observed on stable, “healthy”, reference reach segments of Fountain Creek were used to reconfigure the stream system, which is designed for stability in conveying sediment loads and and withstanding flows ranging from the 2,900 cfs bankfull flow to the 33,300 cfs 100-year flood flow.
Over 1,390 root wad logs and 371 12-inch diameter foundation logs were harvested from the 108,000 acre Spring Creek burn area near La Veta, CO to create interlocking toe wood structures for Phase 2 bank protection. Tiers of wrapped soil lifts with willow stakes places above the toe wood structures completed the Phase 2 bankfull bank stabilization. Phase 1 bank protection was achieved mainly by placing 36 inch diameter (D50) riprap to bankfull height and to scour depth of 8 ft, and also included bend protection using another toe wood structure. The revegetation plan called for the establishment of native willows, cottonwoods, and grasses including: 191,459 willow stakes, 977 cottonwood poles, and 53.9 acres of riparian and upland seed.
The project reach, located about one mile south of Pinon Rd., was designated a high priority in the Watershed Assessment of River Stability and Sediment Supply (WARSSS Segments PC78, PC079, PC081, and PC082) Study (Matrix 2017). This designation indicated that instabilities along the creek’s bank were causing encroachments onto private land and depositing large volumes of sediment. Stabilization provided by the project is estimated to reduce sediment loads on Fountain Creek by over 104,000 tons per year.
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