Frequent flooding caused city to evaluate erosion protection solutions
By May 2015, Vensel Creek was fully vegetated and providing erosion control protection to the community.
Jenks is one of the fastest growing cities in the state of Oklahoma and is the home of the headquarters of Kimberly Clark Corp., First Oklahoma Bank and Tedford Insurance. Frequent flooding from the Arkansas River watershed, particularly Vensel Creek, was causing severe bank erosion throughout several of the town’s residential communities. The erosion was encroaching into homeowner’s back yards and was jeopardizing valuable property.
The existing channel depth ranged from 5 to 15 ft in various locations and had a maximum 100-year storm event velocity of 11.85 ft per second. The native soils in the area consist of clayey sands and low-plasticity clays. Under normal conditions, the water table was 17 ft below the top of the channel, requiring a factor of safety at 1.3 to 1.5.
Traditionally, hard armoring systems such as rock riprap or concrete blocks would have been used to prevent soil erosion, but City of Tulsa Public Works sought a solution to stabilize the stream bank that would have a low impact on the surrounding communities and provide increased stability. The city also wanted a vegetated solution that would enhance the natural beauty of the community and improve water quality. Hard armoring systems are expensive and do not provide the pollutant removal capabilities that vegetated systems offer.
Armormax Engineered Earth Armoring Solution was used to restore the eroded stream bank and protect it from future scouring forces.
The city chose to use Armormax Engineered Earth Armoring Solutions by Propex. Armormax is a combination of high-performance turf reinforcement mats and Engineered Earth Anchors that work together to lock soil in place and protect against hydraulic stresses. This product was chosen because it is more cost-effective and faster to install than traditional hard armoring solutions. Additionally, it promotes mass root development, yielding a fully vegetated solution that provides erosion control and a design life of up to 75 years. The U.S. Environmental Protection Agency (EPA) has recognized that systems reinforced with vegetation protect the soil from scouring forces and enhance vegetative growth, while raising the threshold of natural vegetation to withstand higher hydraulic forces on stabilized slopes, stream banks and channel.
After the Armormax system was installed, the area was hydro-seeded and a temporary erosion control blanket was placed on top to facilitate vegetation establishment. The project was completed in October 2013, and seven months later it was almost fully vegetated. By May 2015, the area was completely vegetated and successfully providing erosion control for the community surrounding Vensel Creek.