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)


   Hydrology (zip)

   Sediment Transport (zip)

   Chemical Transport (zip)

   Radar Rainfall (zip)

Source Code




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 is still under active development. Revisions to the model source code are periodically made available for download.  You can contact the authors through the Contacts link. You may also want to visit the CASC2D-SED web site.


Home | Overview | Applications | User Manual | Examples | Source Code | Contacts

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

Last update: 10 February 2011