From this window you can select the hydrological rainfall-runoff model to be used.
The current default model selected for Designand Analysis runs is shown in the list box to the left.
Clicking the Delete Default Model button deletes the highlighted model.
The Edit Default Model opens a property sheet in which model details can be specified or viewed.
The Add Horton (ILSAX) Model button opens a Horton (ILSAX) model property sheet into which model details can be entered.
The Add Rational Method Model
button opens a rational method model property sheet into which model details can be entered, if this method is enabled in the version of DRAINS that you are using.
The Add Extended Rational Model
button opens a property sheet for the extended rational method model, if the Rational Method is enabled in the version of DRAINS that you are using
The Add Storage Routing Model button opens the storage routing model property sheet into which model details can be entered, if storage routing models are enabled in your version of DRAINS.
This dialog box can be used to set up multiple hydrological models within a DRAINS model and analysed simultaneously by specifying the selected type from the property sheet of a sub-catchment. Different models can be employed in a single network, allowing for different soil types or loss conditions. While DRAINS allows you to create Horton (ILSAX) and Rational Method hydrological models together, it does not allow any runs that mix these types of models in the various sub-catchments of a stormwater drainage system.
It is possible to have a storage routing model in operation with the Horton (ILSAX) or IL / CL model. However, only one type of storage routing procedure - RORB, RAFTS or WBNM, can be implemented. The different models are structured differently and cannot be mixed.