Stream Network and Stream Segment Temperature Models Software

Product Type: 





Bartholow, J

Suggested Citation: 

Bartholow, J. 2010. Stream Network and Stream Segment Temperature Models Software. Fort Collins, CO: U.S. Geological Survey.

This set of programs simulates steady-state stream temperatures throughout a dendritic stream network handling multiple time periods per year. The software requires a math co-processor and 384K RAM. Also included is a program (SSTEMP) designed to predict the steady state stream temperature within a single stream segment for a single time period.


SNTEMP is a mechanistic, one-dimensional heat transport model that predicts the daily mean and maximum water temperatures as a function of stream distance and environmental heat flux. Net heat flux is calculated as the sum of heat to or from long-wave atmospheric radiation, direct short-wave solar radiation, convection, conduction, evaporation, streamside vegetation (shading), streambed fluid friction, and the water's back radiation. The heat flux model includes the incorporation of groundwater influx. The heat transport model is based on the dynamic temperature-steady flow equation and assumes that all input data, including meteorological and hydrological variables, can be represented by 24-hour averages.

Water Quality Applications

SNTEMP was developed to help aquatic biologists and engineers predict the consequences of stream manipulation on water temperatures. Water temperatures may affect aquatic systems in many ways, ranging from acute lethal effects, to modification of behavioral cues, to chronic stresses, to reductions in overall water quality. Manipulations may include reservoir discharge and release temperatures, irrigation diversion, riparian shading, channel alteration, or thermal loading. The model has been used to help formulate instream flow recommendations, assess the effects of altered stream flow regimes, assess the effects of habitat improvement projects, and assist in negotiating releases from existing storage projects.


  • Applies to a stream network of any size or order.
  • Predicts the solar radiation penetrating unshaded water as a function of latitude and time of year.
  • Predicts the riparian and topographic shading of that radiation.
  • Corrects air temperature, relative humidity, and atmospheric pressure as functions of elevations within the watershed.
  • Fills and optionally smoothes missing observed water temperature measurements.
  • Provides statistical goodness-of-fit tables to help judge the model's power of estimation.
  • Uses time steps ranging from 1 month to 1 day.
  • Uses readily available data.


  • Inability to deal with rapidly fluctuating flows.
  • Uses an empirical approach to predicting maximum daily water temperatures.
  • Turbulence is assumed to thoroughly mix the stream vertically and transversely (i.e., no microthermal distributions).

System Requirements

SNTEMP and SSTEMP require Windows 95 or later operating system with at least 640K of memory and 3 megabytes of hard disk storage space.

Software Components

SNTEMP.exe 999 KB A self-extracting file containing program and batch files for the DOS version of SNTEMP. Also includes the Errata file for Information Paper 16. Updated: 01.12.2010 1 MB Source code for SNTEMP. Updated: 04.12.2006
SNUTILS.exe 777 KB A self-extracting file containing utility programs and batch files useful in conjunction with running the Stream Network Temperature Model on Intel compatible computers. Files include DATCHK, DELTAQ, EXERR, READRYAN, TMPFIT, and TSTATS. Updated: 01.12.2010 264 KB A ZIP file containing sample input (KVRF*) and output (KVR*) from the Stream Network Temperature Model (SNTEMP) for verification purposes. Updated: 10.01.2014
SSUNZIP.exe 4 MB A self-extracting file containing program for the Windows version of SSTEMP. Running this program extracts the Setup program and files to install SSTEMP on your computer. Includes the SSTEMP Ver. 2.0 user manual. Updated: 08.29.2002 1 MB Source code for SSTEMP. Updated: 08.29.2002

For more information, contact:

John Risley
USGS Oregon Water Science Center
Phone: 503-251-3279

Related Projects