Scour Characteristics of Saturated Levees Due to Floodwall Overtopping: Fid-Bau Portal

Scour Characteristics of Saturated Levees Due to Floodwall Overtopping

Karimpour, Mazdak / Heinzl, Kyle / Stendback, Emaline / Galle, Kevin / Zamiran, Siavash / Osouli, Abdolreza

One of the major reasons of levee failure is erosion due to overtopping. The overtopping of levees is occasionally the consequence of a flood or hurricane. In these events, the surface layers of levees become saturated in advance of any overtopping due to rain and storm events. In this investigation, the effect of the saturation ratio and almost vertical impingement of overtopped water from floodwall on scour development is studied. For this purpose, laboratory physical models of a typical levee on the banks of Mississippi river with a scale of 1:20 were constructed. A 2.4 mm thick wooden plate, which was embedded in the crest of the levee represented the floodwall. Silty soil materials with various saturation ratios were used to observe scour potential of the soil. In all the tests, the scour development and the stability of the wall were monitored and analyzed for each test during overtopping. Hydraulic and geometric parameters including densimetric Froude number, compaction level, water content, and levee dimensions were recorded to have a representative comparison between the laboratory models and constructed levees in practice. In addition, the erodibility of the levee materials was determined using erosion function apparatus (EFA). The results of EFA tests were compared to physical model test results to explore and discuss the vulnerability of levee systems to erosion when the surface soils are saturated and floodwall overtopping is experienced.