Development of Floating Wave Barriers for Cost-Effective Protection of Irrigation Pond Levees

The earth levees commonly used for irrigation reservoirs are subjected to significant embankment erosion due to wind-generated waves. Large seasonal fluctuations in water level make vegetative bank protection impractical, and other stabilization methods, such as the use of stone or discarded tires, are not acceptable due to ecological or economic concerns. Here, a floating wave barrier made of polyethylene irrigation tubing is designed through a laboratory model study and subjected to a short-term prototype-scale field test. Based on wave characteristics measured in an irrigation pond near Carlisle, Arkansas, a laboratory-scale wave generating flume was designed, constructed, and used to test multiple wave barrier configurations for regular waves in deep and transitional water depths. Wave transmission characteristics were investigated for the following breakwater arrangements: (1) fully restrained, (2) vertically restrained with a single mooring line, and (3) horizontally restrained with piles at both sides of the wave barrier. The test results show that cylindrical pipes can be used effectively and that wave transmission characteristics strongly depend on the draft and mooring configuration of the wave barrier. The use of multiple small cylinders to replace a single large one is validated. A composite design made of two sizes of cylinders joined at the top was chosen for field testing. In the prototype-scale field test, wave amplitudes were reduced by an average of approximately 50%, which translates into a 75% reduction in wave energy.