Dstorm - the Design Storm Wizard

Design storms are synthetic temporal rainfall patterns used as input for flood modeling studies, drainage design and hydrodynamic modeling. Dstorm - the Design Storm Wizard, is a Windows program that creates a time series of rainfall intensities for a storm of given depth, duration, and return period that follows a particular distribution pattern. Its features include:

  • a variety of common rainfall distributions to choose from, such as the Triangular, Huff, SCS, NRCS Regional, Composite, Chicago and Nested distributions as well as a user-supplied custom distribution

  • automatic adjustment of 24-hour distributions to shorter durations

  • optional use of Intensity - Duration - Frequency (IDF) data downloaded from the NOAA Atlas 14 database

  • the ability to copy or save the design storm time series for later use within the EPA Storm Water Management Model (SWMM)

  • deploying Dstorm as an Add-In Tool within SWMM (see below).

Deploying Dstorm as an Add-In Tool for SWMM

  1. Launch SWMM and select Configure Tools from SWMM's Tools menu.

  2. Select Add in the Tool Options dialog box that appears.

  3. Enter the following information in the Tool Properties dialog box that appears:

Tool Name: Design Storm Wizard

Program: Click the Browse button to locate where the dstorm.exe file resides on your disk drive

Parameters: $INPFILE

and check the "Disable SWMM while executing" and "Update SWMM after closing" boxes.

  1. Click OK to close the Tool Properties dialog box and then click Close to close the Tool Options dialog box.

You can now launch Dstorm from within SWMM by selecting the Design Storm Wizard option from the Tools menu. After a design storm has been created in the Wizard, clicking the Save button will save the storm's time series of intensities to a new Time Series object within SWMM which can then serve as a source of rainfall data for a SWMM Rain Gage.