||When a Waterway polygon is not correctly positioned in relation to the DEM this can result in filling up the nearby land with water at the start of the simulation. This will result in a lower water level then is expected from the water level area value. To correct this, a "shoreline" is added at neighbouring cells. At the start of the simulation, these shoreline cells will also be filled with water up to the nearby water level to prevent the initial flush. By default this option is turned on, but can be turned off by changing the attribute to 0.