Tuflow and estry manual Version 3

3.18.1WLL Method A

Each WLL can only have 2 or 3 vertices. To pick up the water level exactly at a node, use a 3 vertex line with the middle vertice snapped to the 1D node. If you use a 3 vertex line across a channel, the channel "thalweg" is taken at the middle vertex, otherwise, for 2 vertex lines the mid-point is used. At this stage, no attributes are used.

The direction of digitising the WLLs is important. They must be from left to right looking in the positive direction of the channel.

Use Read MI WLL in the .ecf file to specify the 1d_wll layer and automatically create 1D map output in the SMS files. Several 1d_wll layers can be specified if required. Triangular elements are created in the SMS .2dm mesh file – view these in SMS to check they have been created correctly.