Spatially Varying Rainfall in SWMM Networks
InfoWorks ICM supports the use of spatially varying rainfall events in SWMM networks to approximate the movement of a rainfall event across a subcatchment. Rainfall profiles can be applied within the rainfall event to geographical regions. The profile is then applied to any subcatchment whose centroid falls within the geographical region. These geographical regions are defined as rain gage boundaries.
Rain Gage Boundaries
When using observed rainfall, there may be data for a number of different rain gages placed in different locations. The region covered by a particular rain gage can be defined in the GeoPlan View, ensuring that the rainfall profile from the correct rain gage is applied to subcatchments and 2D Mesh elements falling within the rain gage boundaries.
When a simulation is run using a rainfall event containing rain gage boundaries:
- Existing rainfall profiles associated with subcatchments are automatically replaced with the correct profile based on subcatchment location
- Rainfall profiles are automatically applied to 2D mesh elements based on mesh element location (provided the Apply rainfall etc directly to mesh elements option is selected for the 2D Zone.)
By default, the rain gauge region that contains the centroid of the subcatchment will be used to provide rainfall data for the entire subcatchment.
See Using Spatial Rainfall in SWMM Simulations for full details.
Detailed instructions on using rain gauge boundaries can be found in the Rain Gauge Boundaries topic.