Daily and seasonal deformations of a Dutch Levee along a tidal river and during dry and wet conditions.

Abstract

Along the river ‘Hollandse IJssel’ in The Netherlands two infiltration test have been executed. In both situations the levee is infiltrated over a stretch of 30 meters by a maximum overflow of 1.8 l/m/s. Dutch design criteria assume that up to a wave overtopping discharge of 1 l/m/s the infiltration at the polder site of the levee will not significantly influence the level of the phreatic line in the levee. In both test the phreatic line is measured during several hours of overflow and infiltration, as well as some days before and after the experiment. During the test also horizontal and vertical deformations of the slope are measured. Daily and tidal deformations due to low and high tides were measured and show that the dike moves horizontally in the order of 2 to 4 mm during each tidal cycle. During overflow in the second test at the end of a dry summer, the levee also swelled and deformations up to 60 mm were measured. In this paper the two tests, the water pressure and deformation measurements and conclusions are presented.