HYDROLOGIC MOELING SYSTEM HECHMS Hydrologic Modeling Event or

Event or Continuous • An Event Model simulates a single storm • A Continuous

Lumped or Distributed l. A Distributed Model is one in which the spatial (geographic)

Conceptual Model l. A Conceptual Model is built upon a base of knowledge of

Empirical Model l An Empirical Model is built upon observation of input and output,

Measured-Parameter l. A Measured-Parameter Model is one in which model parameters can be determined

Fitted-Parameter l. A Fitted-Parameter Model includes parameters that cannot be measured. Instead parameters must

Enter Basin Model Data Basin Data Precipitation Data Computational Time Step

Loss Rate Function (Event, Lumped, Empirical, Fitted Parameter l Initial and Constant-Rate l NRCS

Loss Rate Function Continuous, Lumped, Empirical, Fitted Parameter l Deficit and Constant Rate l

Loss Rate Function Continuous, Distributed, Empirical, Fitted Parameter l Gridded SMA

Transforms l Clark’s Unit Hydrograph l Kinematic Wave l Mod Clark Unit Hydrograph l

Baseflow Models l Exponential Recession l Constant Monthly l Linear Reservoir l No Baseflow

l. Create and Execute a “Run” l. View the Results l. Exit the Program

Slides: 30

Download presentation

HYDROLOGIC MOELING SYSTEM HEC-HMS

Hydrologic Modeling

Event or Continuous • An Event Model simulates a single storm • A Continuous Model simulates a longer period, predicting watershed response both during and between precipitation events

Lumped or Distributed l. A Distributed Model is one in which the spatial (geographic) variations of characteristics and processes are considered explicitly. l A Lumped Model is where these variations are averaged or ignored.

Conceptual Model l. A Conceptual Model is built upon a base of knowledge of the pertinent physical, chemical, and biological processes that act on the input to produce the output

Empirical Model l An Empirical Model is built upon observation of input and output, without seeking to represent explicitly the process.

Measured-Parameter l. A Measured-Parameter Model is one in which model parameters can be determined from system properties, either by direct measurement or by indirect methods that are based upon measurements.

Fitted-Parameter l. A Fitted-Parameter Model includes parameters that cannot be measured. Instead parameters must be found by fitting the model with observed values of the input and output.

Start a New Project

Create Rainfall Gage Data

Enter Basin Model Data Basin Data Precipitation Data Computational Time Step

Loss Rate Function (Event, Lumped, Empirical, Fitted Parameter l Initial and Constant-Rate l NRCS Curve Number (CN) l Gridded SCS CN l Green and Ampt

Loss Rate Function Continuous, Lumped, Empirical, Fitted Parameter l Deficit and Constant Rate l Soil Moisture Accounting (SMA)

Loss Rate Function Continuous, Distributed, Empirical, Fitted Parameter l Gridded SMA

Transforms l Clark’s Unit Hydrograph l Kinematic Wave l Mod Clark Unit Hydrograph l Snyder’s Synthetic Unit Hydrograph l NRCS Dimensionless Unit Hydrograph l User-Specified S Graph l User-Specified Unit Hydrograph