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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Watershed Physical Processes Research » Research » Publications at this Location » Publication #340864
Title: Laboratory experiements of wave induced embankment erosion

Author
item OZEREN, YAVUZ - University Of Mississippi
item Wren, Daniel

Submitted to: American Society of Civil Engineers Hydraulic Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/15/2017
Publication Date: 7/9/2017
Citation: Ozeren, Y., Wren, D.G. 2017. Laboratory experiements of wave induced embankment erosion. American Society of Civil Engineers Hydraulic Conference Proceedings Hydraulic Methods and Experimental Methods Conference at the University of New Hampshire in Durham, New Hampshire July 9-12, 2017. 1-6 pp.

Interpretive Summary: Irrigation reservoirs are used to reduce dependence on limited groundwater resources in the Mississippi river alluvial floodplain, particularly in the state of Arkansas. A typical size for the reservoirs is approximately 10 Ha, with a maximum fetch of approximately 500-600 meters. Unprotected earthen embankments, which are usually made of local soils, display rapid erosion and retreat due to wind generated waves and surface runoff, creating additional cost for producers. Farmers who rely on irrigation reservoirs need an economic basis for selecting a protection method for vulnerable embankments. A review of the literature did not yield a viable approach for relating wave properties to the rate of erosion or retreat of an earthen embankment. The objective of this manuscript is to describe the results of laboratory experiments on cohesive embankment erosion, including the development of theoretical approach, based on the experimental data, for relating wave characteristics to the erosion of an earthen embankment made from cohesive soil. The results of the study provide a means for estimating how much longer an unprotected levee will last, based on a reduction in wave height.

Technical Abstract: Laboratory experiments were performed to quantify wave induced erosion and retreat of cohesive earthen embankments for shallow irrigation reservoirs. The experiments were carried out in a 20.6 m long, 0.7 m wide, and 1.2 m deep wave tank at the USDA-ARS, National Sedimentation Laboratory in Oxford, MS. The wave tank was equipped with a computer controlled piston type wave generator. The bottom of the wave tank was elevated 0.3 m by a false floor, and a model embankment was constructed on the downwave end at a distance of 16.2 m from the wave paddle. The model erodible embankment was prepared using a standardized packing procedure for a soil composed of approximately 1% sand, 90% silt and 9% clay. Dry density of the packed embankment was approximately 1.5 kg/m3, and the initial slope of the bank face was approximately 30 degrees. The model embankment was exposed to wave action for up to 48 hours, and its morphological evolution under the action of regular waves was monitored. Water surface elevation measurements were made using six capacitance water level sensors and a digital SLR camera. An analytical model was developed to predict the bank retreat rate. The analytical solution was validated with experimental measurements. A unified empirical relationship was established for embankment erosion, edge retreat rates, and incident wave height.