Hfam - Version II - Continuous Simulation Model Software
Hfam II is based on the Stanford, HSP, HSPF, SRFM and Seafm family of models. It is a continuous simulation model that does historical or forecast analysis and it includes probabilistic or ensemble forecasts of streamflows, reservoir levels and releases or power production.
Hfam II uses and or simulates physical ‘elements’ in time. These elements are;
- Time Series
- Meteorological Station Data – precipitation, actual evapotranspiration, wind, solar radiation, air temperature, and (optional) lapse rates
- Streamflows, aquifer levels, snow course measurements, reservoir levels
- Diversion demands, instream flows, minimum or maximum reservoir content, reservoir or reach seepage, irrigation applications, pumping from aquifer elements, hydro power demand, minimum and maximum streamflows below reservoirs, atmospheric loading
- Land Segments
- Aquifer Segments
- Glacial Segments
- Low Level Outlets
The number of physical elements in a watershed is unlimited. Simulation runs hourly.
Hfam II does four types of ‘runs’;
Forecast runs are made with deterministic weather forecasts, and are often used for flood forecasts and flood operations.
Analysis runs are made using historic and real-time data for model parameter calibration and for period of record studies of reservoir operations or water yields.
Probabilistic runs (also called Ensemble runs) give exceedance probability for watershed and reservoir conditions in the future based on the current watershed state and future weather.
Optimization runs solve for the current optimal release from a reservoir given current and future values of releases and exceedance probabilities for reservoir inflows.
Meteorological time series inputs for Hfam II are stored in three data bases; forecast, historic and real-time. These data bases can be seamlessly connected in any model run.
Output from Hfam II includes flows and storage in physical elements, heat exchange, and mass and concentration for sediment and nutrients. Statistical summaries of both inputs and outputs are available. Model input and output are in XML, and all model inputs can be verified with Schemas before they are used by the model.
Model outputs are available for all time series. Any XML conversant program, like EXCEL or WORD can use these outputs directly.
Examples of model screens follow: