By Jonlyn Freeman
jonlynf@hotmail.com
No stream or creek is unimportant in the overall scheme of the global environment, according to  Joachim Tourbier, a professor at the Technical University of Dresden, Germany. He and Richard Westmacott, a professor in UGA’s School of Environmental Design, along with a group of 15 landscape architecture students from both universities, cooperated on a streambank restoration project on Little Clouds Creek in Oconee County during the last week of February.
The project also involved students from UGA’s Institute of Ecology and graduates of the ecology program at UGA. The Dresden group, supported by the Deutscher Akademischer Austausch Dienst, was in this country to share environmental design ideas and techniques with U.S. colleagues. They joined in several projects, including this stream restoration on the farm of Mack and Jane Bowen.
Georgia’s streams and rivers have been severely degraded since the 1840s, when cotton became a major crop on the piedmont. The constant cultivation of cotton caused soil to wash off the land and into streams and rivers in great quantity. Much of the sediment was deposited in the flood plains of rivers. Today streams no longer carry such high sediment loads and are cutting through those thick sediment deposits. Westmacott says Little Clouds Creek now flows in an eroding channel, deeply cut into sediments deposited in the flood plain over the past 150 years.
The students from Dresden represented a range of different stages of their program, but they shared an interest and enthusiasm for streambank restoration. They immersed themselves in local history, reacting to the American countryside with astonishment. They were delighted to see a group of wild turkeys making their way through the woods but shocked at a 350-acre clearcut within 50 feet of the creek.
After completing their calculations and site analysis, the students demonstrated their restoration techniques. They used willow trees and branches to build fascines, bundles of branches that are staked against the stream bank to form a sort of organic retaining wall. The fascines were installed in various configurations, depending on the severity of erosion along the creek bank. On severely eroding bends the fascines were layered on top of each other for the whole height of the bank (about two meters). On less vulnerable banks fascines were used to create a series of terraces, and in other areas single fascines were used in a continuous line at the water’s edge, laid flat against the streambank and covered with soil. Once the fascines are in place, the willow will take root and start to grow, the roots providing effective bank protection against erosion.
This approach using vegetation has several advantages over structural methods using concrete or steel piling. Erosion control using rigid concrete structures can actually exacerbate the condition over time. Once a stream starts eroding behind a concrete retaining wall, the wall is frequently undercut and collapses into the stream bed, leaving the stream trashed and the bank exposed to continued erosion. By using living materials like willow, a more flexible barrier is formed that will adapt to the changing form of the channel over time. The vegetation will also improve water quality and provide habitat for wildlife.
Dan Derosa was one of the UGA students involved in the project. A landscape architecture graduate student at UGA, Derosa had had experience in streambank restoration with Americorps. He called Little Clouds Creek “a classic example of a degraded farmland creek” and was especially interested in the “on-the-spot design” undertaken by the restorers.
While one group of students foraged for young willow trees and branches, others stacked the willow on a wooden frame to shape them and then tied them tightly with wire. One diminutive student tied up fascines using her full weight, hanging onto the rope and dangling in mid-air under the frame of the fascine. As the fascines, willow stakes and other vegetation were put in place along the stream bank, the willow bundles took on a sculptural effect that enhanced the beauty of the stream. It is an art that will grow and change within months and provide a healthier stream years from now. |
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