Introduction To Hec-Hms: Bill Scharffenberg Hydrologic Engineering Center
Introduction To Hec-Hms: Bill Scharffenberg Hydrologic Engineering Center
Introduction To Hec-Hms: Bill Scharffenberg Hydrologic Engineering Center
of Engineers
Hydrologic Engineering Center
Introduction to
HEC-HMS
Bill Scharffenberg
Hydrologic Engineering Center
Objectives
Become familiar with the program and learn basic
concepts of program organization, data components,
and simulation runs.
Understand the different hydrologic elements and the
methods available for each one.
See the different types of results visualization and
statistical summaries.
Preview advanced capabilities.
Program Scope
Designed to simulate watershed hydrology.
Surface water modeling.
From meteorology to watershed outlet.
Program Limitations
Deterministic models.
Uncoupled models.
Evapotranspiration-infiltration.
Infiltration-baseflow.
No aquifer interactions.
Constant parameter values.
Dendritic stream systems.
Flow splits possible but limited capability.
Project
Container for main components.
Basin model.
Meteorologic model.
Control specifications.
Subdirectory name
Program Layout
Data Management
Configuration data and parameters.
Files within the project directory.
Automatically created, saved, loaded, etc.
Main Components
Program Application
Basin Map
Hydrologic Elements
Subbasin Infiltration
Loss rate methods:
Deficit constant.
Exponential.
Green Ampt.
Gridded deficit constant.
Gridded SCS.
Gridded SMA.
Initial constant.
SCS curve number.
Smith Parlange.
Soil moisture accounting.
Clark.
SCS.
S-graph.
Snyder.
User-specified.
Other methods:
Kinematic wave.
ModClark distributed.
Subbasin Baseflow
Baseflow methods:
Bounded recession.
Linear reservoir.
Monthly constant.
Nonlinear Boussinesq.
Recession.
Reach
Routing methods:
Kinematic wave
Lag
Modified Puls
Muskingum
Muskingum-Cunge
Straddle stagger
Loss/gain methods:
Constant.
Percolation.
Reservoir
Routing methods:
Storage curve.
Outlet structures.
Specified release.
Possible structures:
Precipitation
Historical methods:
Gage weights.
Inverse distance.
User-specified.
Gridded.
Hypothetical methods:
Frequency storm.
SCS storm.
Standard project storm.
Evapotranspiration
Available methods:
Gridded Priestley-Taylor.
Monthly average.
Priestley-Taylor.
Snowmelt
Temperature index
method.
Subbasin band approach.
Gridded approach.
Simulation Run
View results for the current simulation run using menu or toolbar
Global summary table.
View results for one element in the current simulation run using the
menu, toolbar, or basin map.
Graph, summary table, time-series table.
Element Graph
Continuous Simulation
Gridded Simulation
Precipitation, evapotranspiration, and snowmelt are
defined on a grid cell basis.
Infiltration and excess precipitation is computed
separately for each cell.
ModClark transform method is used to process excess
precipitation into runoff at the subbasin outlet.
Better definition of subbasin response:
Storm is small compared to the subbasin size.
Storm is very heterogeneous.
Parameter Estimation
Depth-Area Analysis
Frequency storm is often used for estimating flows due
to the 100-yr storm or other return intervals.
Large watersheds often have many locations where flow
estimates are required.
It can be tedious to develop storms with the correct area
for each of the locations.
Analysis tool uses a simulation run and automatically
adjusts the storm area for each selected location.
GIS Preprocessor
HEC-GeoHMS can be used to create basin models
using terrain data.
Start with a digital elevation model.
Select a watershed outlet and then GeoHMS
automatically delineates the watershed border and
preliminary subbasins outlines.
Adjust subbasin outlets.
GeoHMS creates a basin model that can be imported
into HEC-HMS and also creates database table of
parameters that can be estimated from terrain and other
supplemental data layers.