West Fork White River Stream Restoration near Brentwood, AR
 Background: The WFWR is a major tributary of Beaver Lake, which is the primary drinking water source for over 300,000 Northwest Arkansas residents. In 1998, the Arkansas Department of Environmental Quality (ADEQ) placed the WFWR on the states 303(d) list of impaired water bodies citing the cause of impairment to be excessive amounts of siltation. The stream remains listed today, and a 2004 ADEQ watershed assessment showed sediment loads from accelerated streambank erosion to contribute 66% of the total sediment load for the WFWR. Based on a study conducted by the WCRC, the Brentwood project location was a high priority site in need of restoration. Streambank erosion measurements taken prior to implementation of the restoration design found lateral erosion rates as high as 13 ft/yr, resulting in approximately 1,400 tons/yr of sediment that entered the WFWR for an average flow year.
 Stream Restoration Design & Implementation: The WCRC utilized a natural channel design approach to reduce streambank erosion and sediment loads. The stream channel dimensions were redesigned to restore the river to a more stable form based on local reference reach data. The new channel design resulted in locating the river away from severely eroding banks and eliminating abrupt and sharp turns in the river channel. Structures made of natural materials were constructed to deflect higher velocity flow toward the center of the channel, further reducing near-bank shear stress and minimizing erosion. The old channel was converted into a series of four settling ponds that act as ephemeral wetlands. The wetland area provides storage, habitat, and filters stormwater from an adjacent state highway. Following storm events, water is retained in this area for several days as it slowly infiltrates through the soil and gravel substrate, filtering out sediment and other contaminants in the water column. 
The preservation and addition of vegetation was a key component of the stream restoration design. During construction, disturbance to existing vegetation was minimized to keep mature root mass intact for additional bank stability. As the new channel was constructed, the disturbed topsoil was stockpiled and later redistributed throughout the site at the end of construction process in order to provide a healthy growing medium. Native plants were harvested from the project site prior to construction activities and were replanted throughout the completed restoration site. Sod mats, layers of soil and live vegetation taken from the fringe of a nearby pasture, were placed on top of the constructed bankfull benches providing instant erosion protection and plant growth. Hundreds of native trees, shrubs, and grasses were planted and native grass and wildflower seeds were distributed throughout the site to provide erosion control, improve the riparian areas, and enhance the terrestrial habitat.
Post Restoration: Several high flow events have occurred since implementation and the stream restoration at Brentwood has proven to be meeting the project objectives. Accelerated streambank erosion has been eliminated; aquatic habitat has been improved; the riparian areas have been enhanced; and sediment loadings to the WFWR from this site have been reduced by over 97% improving the WFWR and Beaver Lake’s water quality.
The WCRC would like to thank their project partners, the Arkansas Natural Resource Commission, U.S. Environmental Protection Agency, Arkansas Game & Fish Commission, Beaver Water District, North West Arkansas Land Trust, and West Fork Watershed Alliance for their contributions to this project.
The Watershed Conservation Resource Center is a non-profit organization that strives to protect, conserve, and restore natural resources by utilizing the watershed approach, environmental outreach, and providing planning and technical assistance to landowners, communities, and government. For more information on this project, please contact Matt Van Eps at (501) 352-7294. |
