Boundaries

A Flood Modeller 2D simulation requires boundaries; a line, point or polygon can be used to specify where water can enter or exit your 2D model.

Boundary condition data are required to provide inputs to drive a simulation, and contain attributes that reference an input data time series, e.g. flows or levels. It can be drawn anywhere within an active area or traced along the edge of one (by using the snapping functionality). The latter option can be used when linking to an associated 1D model.

A model boundary condition is defined by an ESRI shapefile. This file is also known as a 2D model boundary file. This shape can be created in Flood Modeller or any other GIS system that is compatible with the shapefile format. In your model you then associate a boundary data type to your boundary and add data values (either fixed or time varying).

There are multiple options for assigning data to a boundary line:

• Associate a time series dataset defined in a comma separated text file (csv file) – in this case the boundary shape file requires no specific attributes

• Associate a time series or fixed constant value defined in the 2D simulation interface – in this case the boundary shape file requires no specific attributes

• Associate a time series dataset defined in a 1D boundary unit, e.g. QTbdy unit, stored in a 1D event text file (ied file) – in this case the boundary shape file requires an attribute called “node” in which the 1D node name must be entered to enable the 2D solver to look up the required boundary data.