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Oregon Department of Environmental Quality

Water Quality

Total Maximum Daily Loads (TMDLs) Program 

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Analysis Tools and Modeling Review

Analysis Tools

Below are descriptions of various tools that Oregon DEQ uses for water quality analysis. These tools have been developed and are maintained by Oregon DEQ staff members. Listed below are brief descriptions of each water quality analysis tool and links for downloading the applications and their documentation.

This page will be periodically updated. New applications and new versions of current applications will be made available for downloading.


TTools is an ArcGIS extension used to sample geospatial data and assemble high-resolution inputs for the Heat Source model or other water quality analysis.  Appropriate use and application are the sole responsibility of the user.

  • Download: TTools 7.56 ZIP. Requires ArcGIS 9 or ArcGIS 10, Spatial Analyst, and Visual Basic license from ESRI if using ArcGIS 10. Updated November 2009
  • Download: TTools 7.21 ZIP. Requires ArcView version 3.x, Spatial Analyst.  Updated June 2005

Heat Source

Heat Source is a computer model used by Oregon DEQ to simulate stream thermodynamics and hydrology. It was developed in 1996 as a Masters Thesis at Oregon State University in the Departments of Bioresource Engineering and Civil Engineering. DEQ currently maintains the Heat Source methodology and computer programming. Appropriate model use and application are the sole responsibility of the user.


CE-QUAL-W2 is a water quality and hydrodynamic model in 2D (longitudinal-vertical) for estuaries, lakes, reservoirs, and large river systems.  W2 models basic eutrophication processes such as temperature-nutrient-algae-dissolved oxygen-organic matter and sediment relationships.  The current model release enhancements have been developed under research contracts between the US Army Corps of Engineers and Portland State University under supervision of Dr. Scott Wells.  DEQ uses this model for temperature, dissolved oxygen, pH, and other nutrient assessments.


QUAL2Kw is a one dimensional steady state modeling framework written in Excel/VBA.  QUAL2Kw is adapted from the QUAL2K model that was originally developed by Dr. Steven C. Chapra of Tufts University.  DEQ uses this model for dissolved oxygen and pH assessments in rivers and streams.

Modeling Review

[print version]

For more information about DEQ's Total Maximum Daily Loads (TMDLs) Progam contact Gene Foster by phone at 503-229-5325 or by email, or contact the appropriate Basin Coordinator.

Oregon Department of Environmental Quality
Headquarters: 811 SW Sixth Ave., Portland, OR 97204-1390
Phone: 503-229-5696 or toll free in Oregon 1-800-452-4011
Oregon Telecommunications Relay Service: 1-800-735-2900  FAX: 503-229-6124

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