Two-Dimensional Modeling Using HEC-RAS

KENNETH D. PUHN, P.E., CFM, M.ASCE

is a project manager and senior hydraulic engineer with over 20 years of experience in water resources and hydraulic engineering. Mr. Puhn has conducted hydrologic, hydraulic, sedimentation, and geomorphic studies throughout the United States. His project experience includes bridge hydraulic and scour analyses, revetment design, steady and unsteady river hydraulic modeling, hydrologic modeling, flood hazard analysis, dam breach modeling, sediment transport modeling, geomorphic analysis, bank erosion assessments, and reservoir sedimentation studies. Mr. Puhn earned his B.S. in Geology from Northern Arizona University and his M.S. in Water Resource Engineering from Oregon State University. He has also taught dozens of courses on 1D/2D HEC-RAS and streambank stabilization.

Summary

This intensive, workshop-oriented seminar will prepare engineers and water resource professionals 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 a review of 1D unsteady flow, 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.

Prerequisites

Participants should have some experience in floodplain hydrology and hydraulics, and experience and/or training in HEC-RAS steady and unsteady flow computer modeling.

Who Should Attend?

Consulting engineers, water resource planners, and engineers employed by local, state, or federal government agencies.

Course Topics

• Review of 2D Flow Theory 
• Features and Capabilities of RAS Mapper 
• Preprocessing 2D Flow Areas 
• Viewing 2D Model Results 
• Bridges and Culverts in 2D RAS 
• Troubleshooting Errors 
• Differences in 1D versus 2D Modeling 
• Calibrating a 2D HEC-RAS Model 

Course Benefits and Outcomes

Participants will:

• 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