The course provides an introduction to the Hydrologic Modeling System, HEC-HMS, focusing both on using the program and performing watershed studies. The course starts with a summary and overview of the program and the mechanics of constructing watershed models. Then, components of the software are studied in detail.  Major modules include GIS tools, data entry, historic precipitation approaches, computing infiltration and excess surface runoff, transforming excess precipitation to runoff, baseflow, and channel routing. Parameter estimation techniques are taught throughout with instruction about model calibration. Instruction material is supported with workshops that illustrate the basic steps of building a model for project applications. A final project is included that ties together topics to create a calibrated model from scratch. 

The following table provides links to YouTube videos for all lectures. Links are provided to the workshop pages located in the HEC-HMS Tutorials and Guides space. All workshop files can be downloaded from the workshops pages as well. Finally, all PowerPoint files are included below and can be downloaded for reference.  You will need HEC-HMS version 4.11 or newer to open the workshop files. You can download the software from

Lectures and WorkshopsVideos and Links PowerPoint Files

Lecture 0: Overview of Hydrologic Modeling for Studies

This lecture details common purposes and applications of rainfall-runoff modeling within the U.S. Army Corps of Engineers.  Study goals and commonly-utilized rainfall-runoff processes are related to the overall task of model development with consideration given to the intended use of the model.

Overview of Hydrologic Modeling for Studies

Lecture 1: Introduction to HEC-HMS

Lecture and workshop 1 show the basic components of the HEC-HMS software and how to configure the components to create a simulation and visualize results. Steps to create a model are discussed as well.

L 1 all Introduction to HEC-HMS.pptx

Workshop 1: Creating a Simple Model

1.      Introduction

2.      Creating a New Basin Model

3.      Creating a New Meteorologic Model

4.      Creating a New Control Specifications

5.      Creating and Computing a Simulation Run

6.      Viewing Model Results

7.      Viewing Observed Flow 

Lecture 2: HEC-HMS GIS Delineation Tools

Lecture and workshop 2 describe the GIS delineation tools available in HEC-HMS. You can import GIS elements or delineate subbasin and stream elements using terrain data. The delineation tools allow you to customize the hydrologic element network.

a)     Georeference Elements using Shapefiles

b)     Terrain Data and other Helpful GIS Datasets

c)      HEC-HMS GIS Data Management

d)      Building Walls and Burning Streams

e)      Automated Subbasin and Reach Delineation

f)       Customize Subbasin and Reach Delineation

g)      Element Naming and Connectivity

h)      Subbasin Discretization

YouTube Playlist

L 2 all HEC-HMS GIS Delineation Tools.pptx

Workshop 2: Creating a Georeferenced Model using HEC-HMS GIS Tools

1.      Introduction

2.      Creating and Linking Terrain Data into a Basin Model

3.      Preprocessing Terrain Data to Delineate Subbasin and Reach Elements

4.      Using Merge and Split Tools to Customize Subbasin and Reach Delineation

5.      Finalizing the Hydrologic Network 

Lecture 3: Shared Data Components

Lecture and workshop 3 describe three types of data that can be shared throughout the model: paired data, time-series data, and grid data.  The lesson discusses methods for entering or importing the data, managing existing data, and connecting the data to model components.

a)      Time Series Data

b)      Paired Data

c)      Gridded Data 

d)      Gridded Data Import

YouTube Playlist

L 3 all Shared Data Components.pptx

Workshop 3: Introduction to Shared Component Data

1.      Introduction

2.      Creating Time Series Data

3.      Creating Paired Data

4.      Creating Grid Data

Lecture 4: GIS Parameter Estimation Tools 

Lecture and workshop 4 describe GIS tools that can be used to compute physical characteristics for subbasins and reach elements. The lesson also discusses the parameter calculator and how it can be used to process GIS data for estimating model parameters.

a)      Subbasin Characteristics

b)      Reach Characteristics

c)      Parameter Expression Calculator

YouTube Playlist

L 4 a Subbasin Characteristics.pptx


Workshop 4: Applying HEC-HMS GIS Parameter Estimation Tools

1.      Introduction

2.      Computing Subbasin and Reach Characteristics

3.      Estimating Parameters with GIS datasets

Lecture 5: Meteorologic Models - Historic Precipitation

Lecture and workshop 5 provide an introduction to developing meteorologic models for precipitation events that have occurred in the past.  This includes an overview of the role of the meteorological model in a simulation and details on precipitation modeling methods in HEC-HMS.  Two precipitation methods are highlighted: gage weights and gridded precipitation.  Evapotranspiration and snow modeling are included too.

a)      Meteorologic Model Overview

b)      Precipitation Methods

c)      Gage Weights

d)      Gridded Precipitation

e)      Evapotranspiration

f)       Snow Modeling 

YouTube Playlist

L 5 all Meteorological Models - Historic Precipitation.pptx

Workshop 5: Meteorologic Models for Historical Precipitation

1.      Introduction

2.      Gage Weights Precipitation Method

3.      Gridded Precipitation Method

4.      Creating an Inverse Distance Precipitation Model 

Lecture 6: Loss Rate Methods 

Lecture and workshop 6 introduce canopy, surface, and infiltration methods within HEC-HMS.  Multiple infiltration methods are detailed including: Initial Constant, Green and Ampt, and Deficit and Constant.  Strengths and weaknesses of each method are presented in addition to common parameter estimation techniques.

a)      Loss Methods Introduction

b)      Canopy and Surface Methods

c)      Infiltration Methods

d)      Initial Constant Method

e)      Deficit Constant Method

f)       Green and Ampt Method 

YouTube Playlist

L 6 all Loss Methods.pptx

Workshop 6: Applying Loss Methods in HEC-HMS

1.      Introduction

2.      Applying the Initial Constant Loss Method

3.      Applying the Green and Ampt Loss Method

4.      Applying the Deficit and Constant Loss Method 

Lecture 7: Transform Methods

Lecture and workshop 7 introduce the various surface transform methods available in HEC-HMS.  The lesson goes into detail on deriving a unit hydrograph from observed flow as well as discussing 3 popular synthetic unit hydrograph methods: Clark Unit Hydrograph, Snyder’s Unit Hydrograph, and SCS Dimensionless Unit Hydrograph.   

a)      Transform Methods Introduction

b)     Unit Hydrograph Derivation

c)      Clark Unit Hydrograph

d)     SCS Unit Hydrograph

e)      Snyder Unit Hydrograph 

YouTube Playlist

L 7 all Transform Methods.pptx

Workshop 7: Estimating Clark Unit Hydrograph Parameters

1.      Introduction

2.      Estimating Time of Concentration and Storage Coefficient

3.      Time and Concentration and Storage Coefficient Impacts to the Hydrograph

Lecture 8: Baseflow Simulation

Lecture and workshop 8 introduce baseflow methods available in HEC-HMS. The baseflow methods can be used to model the interflow and/or slower responding groundwater flow components of subsurface flow. The linear reservoir and recession baseflow methods will be discussed.

a)      Baseflow Overview

b)      Applying the Recession Baseflow Method

c)      Applying the Linear Reservoir Baseflow Method

YouTube Playlist

Workshop 8: Applying Baseflow Methods in HEC-HMS

1.      Introduction

2.      Applying the Linear Reservoir Baseflow Method

3.      Applying the Recession Baseflow Method

Lecture 9: Channel Routing Techniques

Lecture and workshop 9 introduce open channel flow processes within HEC-HMS.  Several available channel routing methods are detailed including: Lag, Muskingum, and Muskingum-Cunge.  Strengths and weaknesses of each method are presented in addition to common parameter estimation techniques.  Multiple considerations that can be used to select appropriate channel routing techniques are also exhibited.

a)      Introduction to Modeling Open Channel Flow within HEC-HMS

b)      Lag Method

c)      Muskingum Method

d)      Muskingum-Cunge Method

e)      Selecting the Appropriate Routing Technique

YouTube Playlist

L 9 all Open Channel Flow within HEC-HMS.pptx

Workshop 9: Applying Reach Routing Methods within HEC-HMS

1.      Introduction

2.      Applying the Lag Routing Method

3.      Applying the Muskingum Routing Method

4.      Applying the Muskingum-Cunge Routing Method

Lecture 10: Model Calibration

Lecture and workshop 10 discuss the importance of calibrating a hydrologic model, and provide strategies and guidance for performing model calibration.  A detailed look at the impact of several hydrologic parameters on the calibration process and advice for adjusting them in a real world model is included.

a)      Calibration Theory

b)      Calibration Strategies

c)      Parameter Impacts

d)      Calibration Metrics

e)      Model Calibration Advanced

f)      Model Calibration Aids

YouTube Playlist

L 10 e Model Calibration Advanced.pptx

L 10 f Model Calibration Aids.pptx

L 10 all Model Calibration.pptx

Workshop 10: Calibrating a Simple HEC-HMS Model:

1.      Introduction

2.      Populate Initial Parameters

3.      Calibrate a Basin Model to Event 1

4.      Calibrate a Basin Model to Event 2

Project: Develop a Calibrated Model from Scratch

This final workshop combines information from all lessons and gives you another chance to build an HEC-HMS model application. You will create a model from scratch, estimate model parameters, and then calibrate the model to a flood event. 

Link to Final Project