This report is the first part of the comparison study of the two different modelling approaches, idealised modelling using iFlow, and idealised modelling using TELEMAC-3D. The TELEMAC computational domain used in this study is inspired by the iFlow model of the Scheldt estuary from Brouwer et al., 2018. In the iFlow study, the model is used for studying the time evolution of estuarine turbidity maximum (ETM) in the Scheldt. Both computational efficiency and the well-presented physical processes in this iFlow model makes capturing ETM zones possible. However, reproducing ETM dynamics still faces challenges in the TELEMAC-3D or other large-scale complex models. This study tries to find out the necessary model set-ups required for capturing an ETM in a TELEMAC-3D model, with the inspirations from the iFlow model.