Model selection for salt water intrusion in delta areas

Due to land subsidence and sea level rise, salt intrusion in delta areas increases. This is a potential thread for agriculture in these areas. To investigate this thread and measures that can counteract on it, numerical models are developed to mimic the behavior of the water system under different strategies and scenarios. This behavior is characterized by a complex interaction among flows, water levels and salinity concentrations, distributed in time and space. On top of this, controllable structures such as locks and gates, are operated and influence the situation. The selection of the type of model that is used in the investigation is essential for the results.This can range from a 1-dimensional flow model without density flow that is custom for integrated water management to a 3-dimensional fully coupled flow and salinity model. In this paper we describe our experience with model type selection for these types of water systems