This document is the technical reference manual for the Hydrologic Modeling System (HEC-HMS). The program is a product of the US Army Corps of Engineers' research and development program, and is produced by the Hydrologic Engineering Center (HEC). The program simulates precipitation-runoff and channel routing processes, both natural and controlled. The program is the successor to and replacement for the Flood Hydrograph Package HEC-1 (USACE, 1998) and for various specialized versions of HEC-1. The program improves upon the capabilities of HEC-1 and provides additional capabilities for distributed modeling, continuous simulation, and interior flooding analysis.
This technical reference manual describes the various methods included in the program, for example, the Green and Ampt loss method. The development of the mathematical algorithm underlying each method is presented. Information and guidance are provided to assist the user in selecting a method for application and estimating parameters. Details on the solution of the algorithm are also provided.
The presentation is aimed at an engineer or scientist who has studied hydrology in a university-level course. Thus, examples of common methods are not provided; such information may be found by consulting available texts and journals. On the other hand, examples of the computations for the new or uncommon models within the program are included.