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






TREX is written in the C programming language and follows ANSI C99 conventions. Only model source code and makefiles are distributed.  The model code has been compiled and simulations executed on several computing platforms (Windows, linux) with different processors (Intel, AMD, Itanium2) to ensure a degree of portability.

A TREX executable (binary) can be easily created using a C compiler in a development environment such as Microsoft Visual Studio .Net on a PC running the Windows OS. For other platforms, TREX can be compiled using a unix/linux make utility.

Notice: TREX is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Download TREX source code bundle:


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

Last update: 07 August 2018