GGU-DRAWDOWN: The influence of open water

After RIESS (Grundbautaschenbuch 1997), for groundwater drawdown next to open water with a leaky base, the double distance from the centre of the excavation to the water's edge is to be used, instead of the range. For elongated excavations, running parallel to water, the influence increases, in which case the single distance is to be used. This is realised in the program by selecting "= fixed value" as Range R in the "Edit/Base data" menu item and then entering this fixed value (simple or double distance to waters edge) in the menu item "System/Analyse" before starting calculation.