UG_210_2_21 - UG 210-21-2 ENG – HEC-SSP 2.2 Computer Program and Documentation
UG 210-21-2 ENG – HEC-SSP 2.2 Computer Program and Documentation
User Guide: 210-21-2  Date: March 24, 2021
Subject: ENG – HEC-SSP 2.2 Computer Program and Documentation

Purpose.   To announce the availability of the U.S. Army Corps of Engineers (USACE) Hydrologic Engineering Center – Statistical Software Package (HEC-SSP) version 2.2 computer program and explains how to obtain the software and program documentation.
Effective Date.   Effective upon receipt.  
Background.   HEC-SSP is a statistical software package developed by the USACE-HEC in Davis, CA, to perform statistical analyses of hydrologic data. HEC-SSP 2.2 allows users to perform flood flow frequency analyses based on Bulletin 17B, “Guidelines for Determining Flood Flow Frequency,” published by the Interagency Advisory Committee on Water Data in 1982; and  Techniques and Methods Manual 4-B5, “Guidelines for Determining Flood Flow Frequency” (Bulletin 17C), published by the U.S. Geologic Survey. It also allows users to perform generalized frequency analyses on not only flow data but other hydrology data as well, volume frequency analyses on high and low flows, duration analyses, coincident frequency analyses, balanced hydrograph analyses, distribution fitting analyses, and mixed population analyses.

Special Instructions.  HEC developed HEC-SSP for USACE use but distributes the software freely to the public for use without restriction. The user assumes all responsibility for the accuracy and suitability of this program for a specific application. HEC does not provide assistance or support for this software to non-USACE users. HEC provides more information on the software support policy at

Distribution.  NRCS tested and CCE certified HEC-SSP 2.2 on August 1, 2019, for deployment to NRCS Information Technology Services (ITS) supported workstations running Windows 10 x64. The project reference number is RFC CRQ33569747.

This directive cancels, deletes, and replaces the previous notification, “User Guide 210-19-2:  ENG – HEC-SSP 2.1.1 Computer Program and Documentation,” dated March 11, 2019.

NRCS users are to obtain the HEC-SSP 2.2 through their ITS managers, who can download and install the program. NRCS makes no official printing or distribution of program documentation, but users can download it from the HEC-SSP webpage at

Filing Instructions.  Users wishing to retain paper copies of any of the HEC-SSP documentation should place it in a three-ring binder adjacent to other technical directives.     

Contact.   For statistical analysis related technical questions, NRCS users may contact NRCS hydrology and hydraulics personnel at the East, Central, and West National Technology Support Centers, the National Design Construction and Soil Mechanics Center, and the National Water Management Center.

Contact Claudia C. Hoeft, National Hydraulic Engineer, Conservation Engineering Division, by telephone at (202) 720-0772 or via email at  with questions regarding this directive.   



Deputy Chief for Science and Technology                                  
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