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Thomas R. Payne & Associates is now part of the employee owned Normandeau Associates team.  We are the same professional staff with the expanded resources of a nationally recognized company providing high quality, practical environmental solutions.  Visit our Normandeau website also.

Fisheries Biology, Consulting and Software Publishing
890 L Street, Arcata, California USA 95521
P.O. Box 4678, Arcata, California USA 95518
(707) 822-8478

RHABSIM Version 3.0

RHABSIM (Riverine HABitat SIMuation) is a fully integrated program for river hydraulics and aquatic habitat modeling using the Instream Flow Incremental Methodology (IFIM). Running in Microsoft Windows and DOS, it is an extensive conversion of the PHABSIM hydraulic and habitat simulation system developed by the U. S. Fish and Wildlife Service.


All previous versions of RHABSIM are now FREE from Thomas R. Payne & Associates and can be considered public domain software.  Version 3.0 (also available FREE) contains partial fixes for some Windows XP and 2000 compatibility issues (screen sizing and font display drivers) and the program is fully functional.  However, since even RHABSIM 3.0 can be inconvenient to use at times, we are allowing open use until a new version is completed.

UPDATE 08/15/2013

Thomas Payne has collaborated with Ian Jowett and Bob Milhous to create new, comprehensive software that “implements the substance of the IFIM”.  SEFA, System for Environmental Flow Analysis, is available on a new website


You may also view the RHABSIM web site in Spanish (Español).

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CONVERT - File conversions, import and export features


FIELDAT - Field data entry, bottom profiles, velocities and attributes


HYDSIM - Hydraulic calibrations, Stage/Discharge, WSL and Vel modeling


CRITERIA - Species Curve libraries


HABSIM - Habitat simulation, Weighted Usable Area calculations


TIME SERIES - Flow and Habitat Duration Analysis


GLOBAL features and Windows presentation report/graph programs

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RHABSIM Screen Shots

RHABSIM includes six main modules, each performing an integral step toward habitat analysis. Click on a link below to view representative screen shots from each module...

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SPECIFICATIONS and Program Limits

RHABSIM requires the following system specifications:


RHABSIM data files and processing allow the following data limits:

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I need to run a Time Series Flow and Habitat Duration analysis. I have Weighted Usable Area results from a PHABSIM run, but I don't have streamflow data for the river in question. Can RHABSIM import data from the U.S.G.S?

If you are currently a RHABSIM user and have questions about installing and running the programs, see our troubleshooting page.

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We would like to hear from you. E-mail us at: or visit the PRICING and ORDERING page.

Comments or suggestions for the RHABSIM programmer and webmaster can be sent to... Milestone Software

...and thank you for visiting.

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