Wave Overtopping Testing for Levee Landward Side Slope Protection

Full-scale Wave Overtopping Testing for Levee Landward Side Slope Protection was performed on the HydroTurf® Revetment System at Colorado State University – Engineering Research Center (CSU) in Fort Collins, CO. Testing was performed in accordance with the methodology developed for the US Army Corps of Engineers.

CSU Wave Overtopping Test Facility

Photo of CSU Wave Overtopping Test Facility

CSU Wave Overtopping Test Facility

The HydroTurf was installed on a highly erodible soil (silty sand) in the testing trays. The HydroTurf was purposefully installed with a sewn seam down the middle of the test section. The completed testing trays were placed on the slopes (3H:1V with a 25H:1V grade break at the toe) of the Wave Overtopping Simulator.

Testing of the HydroTurf Revetment System was conducted in four (4) phases. The first phase tested the installed HydroTurf up to the limits of the Wave Overtopping Simulator.  At the completion of the first phase, the installed and tested HydroTurf was intentionally damaged before continuing with further testing. The intentional damage consisted of the following:

Phase 2 – Pulverization of the hardened HydroBinder™ infill in order to simulate cracked infill and portions of the surface that had been severely damaged.
Pictures showing Intentional Pulverization of HydroBinderTM Infill

Intentional Pulverization of HydroBinder Infill

Phase 3 – A bullet hole was simulated by driving rebar through the HydroTurf into the underlying subgrade.
Photo of Intentional Damage: Simulated Bullet Hole through HydroTurfTM

Intentional Damage: Simulated Bullet Hole through HydroTurf

Phase 4 – A larger hole was created using a pickaxe to expand the simulated bullet hole.
Photos showing Intentional Damage: Large Hole through HydroTurfTM

Intentional Damage: Large Hole through HydroTurf

Wave Overtop Testing of HydroTurf at CSU

Photos of Wave Overtop Testing of HydroTurfTM at CSU

Wave Overtop Testing of HydroTurf at CSU

The HydroTurf Revetment System withstood the largest wave overtopping loads (4 cfs/ft) that could be applied by the Worldʼs Largest Wave Overtopping Simulator. These loads are the most energetic wave overtopping conditions that can be produced in any existing wave overtopping experimental facility, and they represent a 500 year generic hurricane (0.2 percent annual exceedance probability) in New Orleans, LA. The testing continued for a total of 13 hours with HydroTurf being subjected to 165,600 cf/ft of water volume. The HydroTurf Revetment System performed exceptionally well in
maintaining the underlying, highly-erodible soils during these severe conditions, even in an intentionally damaged state.

The following graph is a comparison of armoring performance for levee landward-side protection for various technologies that have been tested in the CSU Wave Overtopping Simulator. HydroTurf outperformed the other systems. Note that the subgrade for the other technologies was clay while the subgrade for the HydroTurf was highly-erodible sand.

Armoring Performance for Levee Landward-Side Protection from Wave Overtopping

Color Chart for The following graph is a comparison of armoring performance for levee landward-side protection for various technologies that have been tested in the CSU Wave Overtopping Simulator. HydroTurfTM outperformed the other systems. Note that the subgrade for the other technologies was clay while the subgrade for the HydroTurf was highly-erodible sand.

Armoring Performance for Levee Landward-Side Protection from Wave Overtopping