Western Washington Continuous Simulation Hydrology Model (WWHM)

Ecology has released WWHM2012.

WWHM2012 is an updated version of WWHM that includes several new elements related to low impact development (LID). You can find a brief summary of the updates at www.ecy.wa.gov/programs/wq/stormwater/wwhmtraining/summary2012updates.html.

Download the most recent version:

WWHM2012 can be downloaded in three (3) parts:
(version date: 07/06/2015 or later)

  1. Main WWHM2012 software (download and install this first):
  2. Map data for WWHM2012:
  3. WWHM2012 manual (updated May 2014):

WWHM2012 will be updated as we receive comments and make improvements. Check back here for periodic updates.

We are tracking the changes made to WWHM2012. A summary of the change log can be found at:


Please submit your comments to:

Comments may include:

  • The element your comment relates to

  • Your concern and rationale

  • Your suggested improvement or alternative approach

  • Screen shots related to your concern (error messages, data screen)

  • A copy of your .whm project file

Ecology recently offered trainings on WWHM 2012.

You can download the presentation and the WWHM examples at: www.ecy.wa.gov/programs/wq/stormater/municipal/EcyWorkshops.html#WWHMtrainings


How to find out about other WWHM 2012 trainings (for a fee)

For information on training classes on WWHM 2012 please contact Mick Newell at AGC Education Foundation at 206-812-0806. You may also go to their website and navigate to find and register for WWHM 2012 training classes.

Please make sure you include your email address. If you have any questions, please contact Foroozan Labib.

What about WWHM3?

Ecology continues to support the use of WWHM3 for those who choose to do so. It is up to the individual jursidiction to determine the model that is to be used. Check with your jurisdiction to ensure that you are using an accepted model.

Download the current version of WWHM3 and any updates.

If you have questions about WWHM, please contact:
Foroozan Labib
Environmental Engineer
Department of Ecology
Water Quality Program
(360) 407-6439

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