Indicators of Hydrologic Alteration
IHA Software

To Obtain IHA Software

Please fill out this form and you will be directed to the software download (.zip, 9.6 MB).
 

Version 7.1 of the IHA, which is the newest and most advanced version of this software program, is now available and includes many important enhancements including:

 

  1. The ability to compare two different flow datasets. This gives users the ability to compare flows from two different stream gauges or from two different model runs or scenarios covering a similar time frame. The computations are identical to a comparison of two different periods in a single flow dataset. See Introduction to Projects and Project Definition Tab for more information on this option.
     
  2. The Environmental Flow Components algorithm has been improved to simplify the default version of the algorithm, and also to provide greater flexibility in calibration. See EFC Calculation Algorithm and Calibrating the EFC Algorithm for description of these features.
     
  3. Flow duration curves (FDCs) have been added to the IHA. IHA will compute FDCs using the same periods, years, and days used for the 33 IHA statistics. FDC results are displayed in a new tab on the results spreadsheet, and are computed annually and for each month. It is possible to view any number of FDCs on the same graph. See Flow Duration Curves for more information.

Important Note: although Version 7.1 of the IHA will open projects created in Version 7, once that is done, it will no longer be possible to use those projects with Version 7, since some alterations will be made in the IHA data files.

 

System Requirements
The IHA will run under any version of Windows. The installation will require about 4 MB of disk space.

User's Manual
Download the user manual in English (.zip 2.1 MB)

Download the user manual in Spanish (.zip 2.1 MB)
 

Questions or concerns:
Ted Rybicki
tedry@rightwell.com
(530) 798-1636

Scientific papers on the IHA

IHA Applications Database
This document is a list of the various applications to which the IHA has been applied and is designed to help users identify others who are doing similar work, as well as make all IHA users aware of the diversity of possible applications of the IHA.
Applications Database (249 kb .pdf file, updated 6-17-05)


To Obtain IHA Software

Please fill out this form and you will be directed to the software download (.zip, 9.6 MB).

The Nature Conservancy never shares your e-mail address with outside organizations, but we will notify you as new versions of the IHA software become available. (Privacy Statement).

 
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Disclaimer: Because software is inherently complex and may not be completely free of errors, it is your responsibility to verify your work and make backup copies, and TNC will not be responsible for your failure to do so. In no event will TNC be liable for indirect, special, incidental, or consequential damages arising from use of or inability to use this product, including, without limitation, damages or costs relating to the loss of profits, business goodwill, data or computer programs, even if advised of the possibility of such damages. The foregoing limitations shall not apply to claims relating to death or personal injury which arise out of products deemed to be consumer goods under applicable law. Some states do not allow the exclusion or limitation of implies warranties of limitation of liability for incidental or consequential damages, so the above exclusion or limitation may not apply to you.

Any commercial use of this software is prohibited without the express, written consent of TNC.