Soil bioengineering is one of several new and innovative engineering practices being used on the fhwa cumberland gap tunnel project to prevent erosion and provide permanent stream bank protection. Four installations of soil bioengineering, using primarily sandbar and black willow cuttings, were constructed to provide stable and aesthetic creek bank protection and stream redirection for little yellow creek in the cumberland gap national historical park. These four installations included a live boom (stream redirection), a brush mattress, live stakes, and joint planting. During the first 6 months, the dormant, primarily willow stems and trunks in all four installations sprouted new branches, leaves, and extensive roots that retained thesoil and protected the banks in an effective and aesthetic manner. Over the next 2 years, the plant material weathered an officially recorded drought, insect attack, extreme heat and cold, and moderate flooding. Throughout these attacks, the plants showed remarkable resiliency and continued to expand vertically and horizontally both above and below the ground surface. After 3 years of growth, healthy plants up to 6 ft tall are maintaining aesthetic stream bank protectionand their root system has stabilized the soil that makes up the stream bank slopes. This paper appears in transportation research record no. 1291, Fifth international conference on low-volume roads, may 19-23, 1991, raleigh, north carolina, volume 2.
Abstract