Experiment No. 12
INTRODUCTION TO HEC-HMS SOFTWARE
Object:- Introduction to HEC (Hydrologic Engineering Centre)-HMS (Hydrologic Modeling System) Software.
Apparatus:- HEC-HMS Software
Theory:- The hydrologic modeling system is designed to simulate precipitation runoff processes of watershed systems. designed to be applicable in a wide range of geographical areas for solving the widest possible range of problems. This includes large River basin water supply and flood hydrology, at small urban or natural watershed runoff. Hydrograph produced by the system or program are used directly or in conjunction with other software for studies of water availability, urban drainage, flow forecasting, future urbanization impact, reservoir spillway design flood damage reduction, floodplain regulation, and system operation.
The program is generalized modeling system capable of representing many different watersheds. A model of the watershed is constructed by separating the hydrologic cycle into manageable pieces and constructing boundaries around the watershed of interest. Any mass or energy flux in the cycle can then be represented with a mathematical model. In most cases, several model choices are available for representing each flux. Each mathematical model included in the program is suitable in different environments and under different conditions. Making the correct choice requires knowledge of the watershed, the goals of the hydrologic study, an engineering judgment.
The program features a completely integrated work environment including a database, data entry utilities, computation engine, and results reporting tools. A graphical user interface allows the seamless movement between the different parts of the program. Program functionality and appearance are the same across all supported platforms.
Capabilities of HEC-HMS Software:- The HEC-HMS Software has wide array of capabilities. Most common methods are included, and the complex tasks are performed in such a way that it makes the user concentration free.
1. Watershed Physical Description
2. Meteorology Description
3. Hydrologic Simulation
4. Parameter Estimation
5. Analyzing Simulations
6. Forecasting Future Flows
7. Sediment and Water Quality
8. GIS Connections
Hydrologic Elements of HEC-HMS Software: The HEC-HMS consists of seven hydrologic elements listed as under, used to perform various simulations.
1. Subbasin – rainfall-runoff computation on a watershed.
2. River reach – routing of flows from one end of a reach to the other.
3. Reservoir – routing of flows through a level-pool reservoir.
4. Junction – combination of flows from upstream reachs and subbasins.
5. Diversion – abstraction of flow from the stream.
6. Source – inflow of water from a stream crossing the boundary of the modeled region.
7. Sink – outflow of water in a stream crossing the boundary of the modeled region (basin outlet).