The U.S. Army Corps of Engineers (USACE), Hydrologic Engineering Center's (HEC) Statistical Software Package (HEC-SSP) is software that allows users to perform statistical analyses of hydrologic data.
The first official version of HEC-SSP (Version 1.0) was released in August of 2008. Version 1.1 was released in April, 2009 and included improvements to data entry, results visualization and reporting, and added capability to the Volume Frequency Analysis. Version 2.0 was released in October 2010 and included three new analyses: a Duration Analysis, a Coincident Frequency Analysis, and a Curve Combination Analysis. Version 2.1, released in July 2016, included improvements to the volume frequency analysis, general frequency analysis, and Bulletin 17 analysis as well as a new Balanced Hydrograph analysis.
Version 2.2, released in June 2019, includes improvements to nearly all previously-released analyses, two new analyses (Distribution Fitting and Mixed Population), a redesigned Curve Combination analysis, and enhanced data usage and manipulation. These new features and options are discussed in the User's Manual for Version 2.2.
The HEC-SSP software was designed by Michael Bartles, Beth Faber, Matthew Fleming, Greg Karlovits, William Lehman, Gary Brunner, and Jeff Harris. The HEC-SSP user interface and computation code was programmed by Resource Management Associates. This manual was written by Michael Bartles, Gary Brunner, Matthew Fleming, Beth Faber, Greg Karlovits, and Julia Slaughter.