engleski

Resistance of levees against surface erosion due to overtopping on the example of reconstructed breached levees on Sava river in Croatia

Following the major flood event on Sava river in Croatia in the 2014 remediation measures on breached levees were undertaken. Levees were reconstructed and strengthened following the guidelines from CIRIA International Levee Handbook (2013). Having in mind the constant climate changes which cause ever increasing flood levels the need to increase resilience of the structure to accommodate situations which exceed designed loadings has been discussed. In the ultimate limit states (ULS) defined in Eurocode 7 there are no specific requirements with regard to the method of verifying external erosion limit state mechanism. In this paper a further discussion on design situations and water levels exceeding top of embankment (overtopping) has been made, as well as design considerations to increase robustness of the structure. As many levees are designed to flood events reaching embankment’s crest it is a reasonable assumption that, due to the imperfections in the geometry, settlements etc., overflow happens. Surface erosion of the airside slope can quickly progress and cause a levee failure. It is suggested that for levees on waterways without designed discharge spillways a calculation of potential surface erosion on airside is made, regardless of embankment’s design freeboard so that the resistance to surface erosion is ensured.

levee, external erosion, overflow, erosion rate, limit state, grass type

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