TREX: Two-Dimensional Runoff Erosion and Export

Spatially Distributed Model To Assess Watershed Hydrology, Sediment Transport, and Contaminant Transport and Fate




   Extreme Storms (pdf)

   Metals Transport (pdf)

User Manual (pdf)

Source Code


   Hydrology (zip)

   Sediment Transport (zip)

   Chemical Transport (zip)

   Rainfall Options (zip)

TREX Tools






Welcome to the TREX watershed model web site.  TREX is the latest member of Colorado State University's family of watershed models.  Using the links to the left or below, you can download:  (1) an overview of TREX development; (2) detailed information regarding TREX applications; (3) a user manual; (4) model source code; and (5) example files

TREX is a research tool.  Feel free to download model source code and example files.  However, it is provided without any explicit or implicit warranty. The authors cannot offer technical support without special arrangements but would appreciate being advised of programming errors. If you use TREX or modify it for your own research, the authors ask that you credit our contribution with the following citations: 

    Velleux, M., England, J., and Julien P. 2008. TREX: Spatially Distributed Model to Assess Watershed Contaminant Transport and Fate. Science of the Total Environment, 404(1):113-128.

    England, J., Velleux, M., and Julien, P. 2007. Two-dimensional simulations of extreme floods on a large watershed. Journal of Hydrology, 347(1):229-241.

TREX undergoes development as driven by research needs. Revisions to the model source code are periodically made available for download. The developers also have a series of TREX Tools that may be shared with collaborators or new users upon request. You can contact the authors through the Contacts link.

Since its initial development, researchers at Colorado State Univerity and elsewhere have applied TREX or modified it to create new models to solve a wide range of problems. A compilation of a few of these TREX applications and adaptations is provided on the Research link.

You may also want to visit the CASC2D-SED web site.


Home | Overview | Applications | User Manual | Source Code | Examples | TREX Tools | Research | Contacts | USEPA SAP Review

Department of Civil and Environmental Engineering - Colorado State University
Fort Collins, Colorado 80523-2028  USA   (970) 491-5048

Last update: 07 August 2018