In this report, an experimental investigation of the influence of currents on submarine slope stability is presented for the Eastern Scheldt storm surge barrier case. Slope instabilities, including liquefaction failures, have been observed in the scour hole slopes near this barrier. The currents above the sloping bed are expected to initiate the liquefaction slope failures. The effects of the excess pore water pressure increase, that is generated by the currents, on the soil response are investigated by triaxial tests. Multiple excess pore water pressure rates are applied on a loose soil sample. The triaxial tests show that higher excess pore water pressure rates result in earlier developments of strains at lower stress ratios. This research is intended as a step towards a better understanding of the initiation mechanism of the liquefaction slope failures near the barrier.

Terminos Lagoon is the biggest and ecologically most important fluvial-lagoon system of the southern Gulf of Mexico. Rivers, sea and meteorology all influence the lagoon, variable over the year, resulting in a complex situation. To protect this area, it is crucial to know how different hydrological processes, hydrodynamic processes and spatial characteristics influence each other in this context. Using a multidisciplinary approach, this research focused on the question: What is the influence of hydrological and hydrodynamic processes on spatial characteristics of Terminos Lagoon, now and in the future? The study has shown that evaporation has a larger part in the water balance during dry season, where during other seasons the water balance is similar to the annual mean. It is found that the western part of Terminos Lagoon shows different characteristics than the eastern part, as river discharge plays a larger role in the western part of the lagoon. Secchi depth, temperature, dissolved oxygen, sediments and salinity are all different here compared to the eastern part of the lagoon. Salinity and river discharge, as well as air and water temperatures, show to be highly correlated. A tidal watershed divides the lagoon in two approximately equal areas, following the mentioned separation of east and west. Residual currents flow along the boundaries of the lagoon from east to west. A circular residual current in the lagoon is observed near the Puerto Real inlet in created temperature and Secchi depth maps. Nortes season shows highest salinity and lowest Secchi depths, where dry season shows lowest salinity. Both inlets are expected to sedimentate and sediments outside the lagoon move westward. Climatological influences are uncertain, though likely effects are increased water temperature, salinity, flushing time and a decrease in residual current. Mentioned effects are likely most noticeable in the eastern part of the lagoon. Further research is necessary to achieve ecological goals in the region.