This case study originally appeared in SWS September 2021 issue as "Hydromulching Completes Fountain Creek Bank Restoration Project"
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In June 2015, floodwaters streamed down Fountain Creek at a rate of nearly 18,000 cubic feet per second causing a realignment of the waterway, migrating east and causing a sharp turn against the eastern abutment of the Highway 47 bridge. The Colorado Department of Transportation (CDOT) performed emergency repairs to straighten the channel, which protected the bridge but accelerated bank erosion. Over the next three years, a $6 million restoration project was undertaken in partnership with CDOT and Fountain Creek Watershed Flood Control and Greenway District to stabilize Fountain Creek, reduce downstream sedimentation, restore riparian aquatic and terrestrial habitat and protect the area from further erosion.
Riprap protection along bridge abutments provides scour protection at the bridge. A guide bank upstream of the bridge improves hydraulics through the bridge, reducing scour potential. Realignment of the channel provides a more stable slope and natural planform. Riprap bend protection defends against bank erosion and channel migration.
Revegetation provides bank and floodplain stabilization and improves the health of the riparian corridor. Hydromulching was accomplished by Total Terrain, a Pueblo-based storm water management and erosion control contractor using a Bowie Imperial 3000.
Flexterra HP-FGM, a wood-based fiber-mulch that is safe for fish and wildlife, and a floodplain restoration seed mixture was boom sprayed at rate of 4,000 pounds per acre.
Seeding of the floodplain and surrounding area was accomplished harnessing productive capacity of the 3,000-gallon hydromulcher and its 5x3 centrifugal pump, which kept the viscous matrix flowing.
The project was completed in November 2018 before the winter snows. Proprietary chemistry and locking fibers that when dried, provide similar erosion control properties as a rolled erosion blanket, protected the floodplain until the seedbed germinated in the spring. The project has had high resiliency and is working according to design withstanding subsequent heavy rains and flood events.