Predicting equilibrium mud-flow profiles on sea dikes from rheology: field evidence from the Rijpdijk pilot
Type:
Presented during:
CEDA Dredging Days 2026
Authors:
E. Meshkati, R. Voeten, M. van den Heuvel, A. Talmon, Q Bi, W. van der Star and H. van Norel
Abstract
The Pilot Rijpdijk on the Dollarddijk (Nieuwe Statenzijl, NL) investigates whether thin layers of harbor mud from Delfzijl can be applied on the slope of an existing sea dike and allowed to ripen into dike-quality clay soil. Seven test plots are being operated through the summer of 2025 with EcoShape and partners. The aim is to mechanically dredge the mud from the Kanaalhaven (Delfzijl) and transport it to the dike site at Nieuwe Statenzijl by barge, where the mud via a ~15 cm pipeline over ~200-400 m and ~15 m elevation head using a submerged pump. The mud was then allowed to flow over the dike slope to achieve coverage. Under the umbrella of this pilot, placement was monitored and a simple model was developed to predict the equilibrium downslope profile formed during the placement phase as a function of mud rheology and density. Such a quick assessment model can be used for the design of similar projects in the future. Therefore, for selected plots in this pilot, high-resolution 3D laser scanning and particle tracking imagery were carried out during and immediately after placement to capture the thickness and flow velocity of the mud profile on the dike. Several soil samples were taken to measure basic soil properties as well as rheology and density of the material. A simple analytical model, based on mechanical-equilibrium concepts, was developed to estimate the mud profile as a function of density and rheology. The predictions from this model and the measured profiles were in remarkably good agreement. A short summary of field observations-especially with a view toward consolidation and desiccation of the material on the dike-is provided. Additionally, using this model, a scenario analysis was carried out to investigate various future scenarios.