The Hydrologic Modeling System (HMS), written by the Hydrologic Engineering Center (HEC), simulates a watershed's rainfall-runoff process. It is designed to replace HEC-1, and has similar options to HEC-1, but incorporates some advances in hydrologic engineering. These advances include (1) a linear quasi-distributed runoff transform (called ModClark) for use with gridded precipitation, (2) continuous simulation capabilities with either a one-layer or more complex five-layer soil moisture method, and a parameter estimation option. HMS also incorporates a graphical user interface (GUI) for entering hydrologic data, where HEC-1 data was entered using text input files. WMS 7.1 and later versions provide tools for setting up, computing data for, and entering data for HMS models. These models can then be saved to HMS format and the model can be run in HMS. The results from these models can then be read into and viewed in WMS.
You may wonder why you would set up and run an HMS model in WMS when you can just do it in HMS. The reason you would do this is because WMS provides GIS, watershed modeling, and HMS parameter computation capabilities all in one place, while HMS does not provide this.
The HEC Data Storage System (DSS) is a format that was previously unsupported in WMS. Since HMS uses this format for importing and exporting time series data, WMS 7.1 and later versions now support importing and exporting DSS files, allowing for reading and writing time series data from and to HMS.
All the HMS data is entered using one of three dialogs. These dialogs are meant to correspond to the three different types of data entered in HMS: The HMS meteorologic data, the control data, and the basin data. The first dialog used in WMS is the HMS Properties dialog, shown below:
The second is the HMS Meteorologic Model dialog, shown below:
The final dialog is the HMS Job Control dialog:
Related Topics:
Opening an HMS File
Post Processing HMS Results
Running HMS
Saving an HMS File