The program CLOSIM has been written to simulate the practice of the closure of tidal basins. It has not been the aim of the program to provide a new design application or to have any scientific value with respect to the results of the calculations. The simulations should rather give insight in the way closures take place, and in the problems that might be encountered when closing the connection between a tidal basin and the sea. The dataset contains the software and the data used in calculations.@en