Biotechnical Installation and Plantings for Erosion

Control Along the Atlantic Intracoastal Waterway

A collaborative project among Clemson’s Baruch Institute of Coastal Ecology and Forest Science, Charleston district Corps of Engineers, Waterways Experiment Station, Natural Resources Conservation Service, and orry County

During 2000, a demonstration planting to examine the use of native plants as an erosion control method was initiated on an existing Corps of Engineers containment area near Carolina Forest, an 18,000-acre site under development near Myrtle Beach, SC. The slope along the Intracoastal waterway was partly vegetated with mixed species, including mainly kudzu n the upper slope and three-square bulrush and phragmites on the lower lope. Wattling (or live fascines) as a means of stabilizing the slope. This method of soil bioengineering uses long bundles of live willow branch cuttings bound together in long rows and placed in hallow trenches following the contour on dry slopes. To monitor the sprouting, growth, and survival of the wattling, five transects were established on the slope.

Each transect is 10 feet wide and runs from the top of the slope to the bottom of the slope. Beginning in April, the percent of each row that sprouted was estimated and the maximum height of the sprouts and live stakes recorded biweekly. A planting program was initiated on the slope in July 2001. The containment dike slope was divided into thirds and each section was designated to receive either trees, shrubs, or grasses. Beginning on July 6, 2001, the contractor began planting the containment dike slope. Planting continued through July 10, 2001 until all trees, shrubs, and grasses were in the ground. Species and treatment (with or without fertilizer, with or without polymer) were based on a planting matrix developed for the project.

Of the approximately 3300 ft of wattling bundles placed on the slope, 88% sprouted within 6 weeks. The percent of wattling length with live sprouts declined during May to 71%, but watering plus rainfall led to additional sprouting so that by the end of August, 90% of the wattling length has sprouts growing from it. Of the live stakes installed, 100% of them sprouted and only 4% died during the summer.

Lead Investigator: Dr. William Conner, Professor