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Two-Dimensional Modeling Using HEC-RAS

Instructor: J. Paul Rinehimer, Ph.D., A.M.ASCE
*Should the above instructor be unavailable to teach, a qualified WEST Consultants instructor will be appointed to replace him.

This is a hands-on seminar. You must bring your own laptop.

Purpose and Background

This intensive, workshop-oriented, two-day seminar will prepare the engineer and water resource professional to use the HEC-RAS computer program for modeling two-dimensional (2D) unsteady flow applications. Led by experts from WEST Consultants with practical experience in hydraulic modeling, participants will learn how to approach and construct a 2D model for unsteady flow conditions and to effectively view and analyze results.

The seminar includes lectures on 2D flow theory, an introduction to the new capabilities and features of HEC-RAS, and procedures for creating a stable and calibrated 2D model. Workshops focus on giving students hands-on experience with building and pre-processing the computational mesh, performing offline and inline 2D projects, and using the built-in feature RAS Mapper to spatially analyze results.

The HEC-RAS modeling system was developed as part of the Corps of Engineers Hydrologic Engineering Center Next Generation software and replaces several existing programs including HEC-2, UNET, and HEC-6. HEC-RAS incorporates various aspects of 2D hydraulic modeling including flow and water surface profile and computations within storage areas and the interaction between 1D and 2D systems. Version 5.0 of HEC-RAS includes features in 2D open channel hydraulic analysis such as:

  • Two-dimensional flow analysis using the full St. Venant or diffusion-wave equations in 2D.
  • Ability to perform a combination of 1D and 2D flow analysis in the same model.
  • The use of unstructured or structured computational meshes for the 2D flow areas.

HEC-RAS is user-friendly, computationally efficient, and runs within and fully supports the Microsoft Windows environment. It uses the latest graphical user interface (GUI) technology for data entry, graphics, and display of program results. Complete context-sensitive help screens are available for every program feature and option. Software includes the following functions: file management, data entry and editing, hydraulic analyses, tabulation and graphical displays of input and output data, reporting facilities, and on-line help.

Seminar Benefits/Learning Outcomes

  • Learn how to use the U.S. Army Corps of Engineers HEC-RAS (River Analysis System) computer program to model two-dimensional unsteady flow hydraulics.
  • Get an overview of two-dimensional flow theory and the differences between one-dimensional modeling.
  • Gain hands-on HEC-RAS experience by participating in practical computer workshops.
  • Understand how to develop a stable and calibrated two-dimensional flow model.
  • Obtain valuable insights in methods for minimizing computation errors and instabilities for two-dimensional unsteady hydraulic models.
  • Learn from real-world projects and applications.

Assessment of Learning Outcomes

Instructor(s) will observe student performance during multiple computer workshop problems and students will take a test at the end of the class with questions addressing these items. The test will be graded in class by their classmates as the instructor goes over each question and answer.

Special Features

Workshop participants receive the following publications and software:

  • HEC-RAS software (latest version)
  • HEC-RAS Course Notes and Workshop Problems
  • HEC-RAS User Manual (on CD)
  • HEC-RAS Hydraulic Reference Manual (on CD)
  • HEC-RAS Applications Manual (on CD)
  • HEC-RAS Example Problems (on CD)

Who Should Attend

Consulting engineers, water resource planners, engineers employed by local, state, or federal government agencies. Participants should have some experience in floodplain hydrology and hydraulics and sound experience in HEC-RAS steady and unsteady flow computer modeling. They should also be able to follow simple computer instructions.

Seminar Outline | 1.6 CEUs

Day 1

9:00 a.m.–5:00 p.m.

  • Introduction to Two-Dimensional Modeling (2D) in HEC-RAS
  • HEC-RAS Unsteady Flow Review
  • Computer Workshop on Lateral Structures and Storage Areas
  • Review of 2D Flow Theory
  • Features and Capabilities of RAS Mapper

Day 2

8:00 a.m.–4:30 p.m.

  • Computer Workshop on Creating a 2D Mesh
  • Preprocessing 2D Flow Areas
  • Computer Workshop on Offline 2D Projects
  • Viewing 2D Model Results
  • Computer Workshop on Inline 2D Projects
  • Troubleshooting Errors
  • Differences in 1D versus 2D Modeling
  • Computer Workshop on Troubleshooting Errors
  • Calibrating a 2D HEC-RAS Model
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