Getting Started with HEC-HMS: Installation and First Launch

HEC-HMS (Hydrologic Engineering Center - Hydrologic Modeling System) is a comprehensive, free software package developed by the U.S. Army Corps of Engineers (USACE) for simulating the rainfall-runoff processes of watersheds. This tutorial guides you through downloading, installing, and launching HEC-HMS for the first time.

What Is HEC-HMS?

HEC-HMS is the standard hydrologic modeling software used throughout the United States for flood studies, dam safety analyses, and watershed management. It is designed to simulate the precipitation-runoff processes of dendritic watershed systems.

Key Capabilities

HEC-HMS can:

• Simulate rainfall-runoff response from single storms or continuous precipitation
• Model infiltration and losses using multiple methods (SCS Curve Number, Green-Ampt, and more)
• Route flows through channels and reservoirs using various routing techniques
• Analyze reservoir operations including dam spillway performance
• Compute drainage area response for flood frequency analysis
• Support GIS integration through HEC-GeoHMS and other tools

When to Use HEC-HMS

HEC-HMS is appropriate for:

System Requirements

Before installing HEC-HMS, verify your computer meets these requirements.

Minimum Requirements

Recommended Specifications

For complex models with many subbasins and meteorologic data:

Downloading HEC-HMS

HEC-HMS is available free of charge from the official HEC website.

Step 1: Visit the HEC Website

Navigate to the official Hydrologic Engineering Center software page: https://www.hec.usace.army.mil/software/hec-hms/

Step 2: Access the Download Section

1. Click on the Downloads tab or section
2. Review the current version information (4.x series)
3. Note any release notes or known issues

Step 3: Download the Installer

1. Click the download link for the Windows installer
2. You may be required to register or accept the license agreement
3. The download file is approximately 150-200 MB
4. Save the file to a known location (e.g., Downloads folder)

Step 4: Verify the Download

The HEC website may provide checksums (MD5 or SHA) to verify your download:

1. Compare the published checksum with your downloaded file
2. Use Windows PowerShell or a checksum utility to verify
3. Re-download if checksums do not match

Installing HEC-HMS

The installation process is straightforward but requires administrator privileges.

Step 1: Run the Installer

1. Locate the downloaded file (typically HEC-HMS-4.x-Win64.exe)
2. Right-click and select Run as administrator
3. If prompted by User Account Control, click Yes

Step 2: Accept the License Agreement

1. Read the software license agreement
2. HEC-HMS is public domain software developed by the U.S. Government
3. Click I Agree to accept the terms and continue

Step 3: Choose Installation Location

1. The default installation path is C:\Program Files\HEC\HEC-HMS\4.x
2. You can change this location if needed
3. Ensure you have write permissions to the selected directory
4. Click Next to continue

Step 4: Select Components

The installer includes several components:

Keep all components selected for the complete experience.

Step 5: Create Shortcuts

Choose whether to create:

• Desktop shortcut: Quick launch from desktop
• Start Menu folder: Access from Windows Start menu

Both options are recommended for convenience.

Step 6: Complete Installation

1. Review your selections on the summary screen
2. Click Install to begin the installation
3. Wait for files to copy and configure (2-5 minutes)
4. Click Finish when complete

First Launch and Initial Setup

Starting HEC-HMS

Launch HEC-HMS using one of these methods:

1. Desktop Shortcut: Double-click the HEC-HMS icon
2. Start Menu: Navigate to Start > HEC > HEC-HMS 4.x
3. File Association: Double-click any .hms project file

The Welcome Screen

When HEC-HMS opens, you will see the main application window with:

• Menu Bar: Access to all commands and functions
• Toolbar: Quick access buttons for common operations
• Watershed Explorer: Panel on the left showing project components
• Desktop Area: Central workspace for maps and editors
• Component Editor: Panel on the right for editing element properties
• Message Log: Bottom panel showing status messages

Understanding the Interface Layout

The HEC-HMS interface is organized around four key areas:

Initial Configuration

Before creating your first model, consider these configuration settings.

Setting Java Memory Allocation

For larger models, increase the Java heap size:

1. Close HEC-HMS if running
2. Navigate to the installation directory
3. Edit the HEC-HMS.config file (or create a custom configuration)
4. Increase the -Xmx parameter (e.g., -Xmx4g for 4 GB)

Configuring Default Directories

Set your preferred working directories:

1. Go to Tools > Program Settings
2. Configure the Default Directory for projects
3. Set paths for temporary files if using network storage

Display Preferences

Customize the display to your preference:

1. Access View menu options
2. Toggle panels on or off as needed
3. Adjust map display settings through View > Map Layers

Unit System

HEC-HMS supports both US customary and SI (metric) units:

Exploring Example Projects

HEC-HMS includes example projects that demonstrate different modeling scenarios.

Accessing Examples

1. Go to File > Open
2. Navigate to the HEC-HMS installation directory
3. Open the examples subfolder
4. Select a sample project to explore

Available Examples

These examples are excellent learning resources. Open each one, examine the setup, run the simulation, and explore the results.

Where to Find Help

HEC-HMS provides extensive documentation and support resources.

Built-In Documentation

Access help directly from HEC-HMS:

1. Help > Help Topics: Open the complete user manual
2. Help > About: View version information and credits
3. Context-sensitive help: Press F1 in most dialogs for specific guidance

Official Documentation

Key references from USACE:

Online Resources

• HEC Website: Official downloads and documentation
• USACE Webinars: Recorded training sessions
• HEC-RAS/HMS Forums: Community discussions
• University Courses: Academic training materials

Troubleshooting Common Issues

HEC-HMS Will Not Start

Java-related errors:

• Verify Java is installed (included with HEC-HMS installer)
• Check that no conflicting Java versions are interfering
• Ensure 64-bit Java is being used on 64-bit Windows

Insufficient memory:

• Close other applications
• Increase Java heap size in configuration file
• Verify system has adequate RAM

Permission errors:

• Run as administrator for first launch
• Check write permissions to installation directory
• Avoid installing to protected system folders

Display Issues

Blank or corrupted display:

• Update graphics drivers
• Disable hardware acceleration if available
• Check monitor resolution and scaling settings

Text or icons too small:

• Adjust Windows display scaling
• Modify font settings in HEC-HMS preferences

Performance Issues

Slow application response:

• Increase Java memory allocation
• Close unnecessary background applications
• Use SSD storage for project files

Simulations running slowly:

• Reduce output time intervals
• Simplify model where appropriate
• Check for excessive error messages in log

File Association Issues

Cannot open .hms files by double-clicking:

• Re-run installer and select file associations
• Manually associate .hms files with HEC-HMS executable

Understanding HEC-HMS Projects

A HEC-HMS project consists of several integrated components.

Project Structure

File Types

Project Organization

HEC-HMS creates a folder structure for each project:

ProjectName/
├── ProjectName.hms (main project file)
├── ProjectName.basin
├── ProjectName.met
├── ProjectName.control
├── ProjectName.dss
└── ... (additional files)

Next Steps

Now that HEC-HMS is installed and running, you are ready to:

1. Create your first model: Your First HEC-HMS Model
2. Understand subbasins: Subbasin Elements Basics
3. Learn calibration: Model Calibration

References

1. U.S. Army Corps of Engineers, Hydrologic Engineering Center. (2024). HEC-HMS User’s Manual. Davis, CA: USACE.

2. U.S. Army Corps of Engineers, Hydrologic Engineering Center. (2024). HEC-HMS Technical Reference Manual. Davis, CA: USACE.

3. U.S. Army Corps of Engineers, Hydrologic Engineering Center. (2024). HEC-HMS Quick Start Guide. Davis, CA: USACE.

Summary

You have successfully installed HEC-HMS and are ready to begin hydrologic modeling. Key takeaways:

• HEC-HMS is free, powerful software for watershed modeling developed by USACE
• Download only from the official HEC website
• The software includes Java, so no separate installation is required
• Explore the example projects to learn HEC-HMS capabilities
• Configure memory settings for larger models

Continue to Your First HEC-HMS Model to start building a watershed model.