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Evaluating project stability and sustainability using two-dimensional (2D) hydraulic models in stream restoration assessment and design

Instructors: Jeremy Payne, P.E., Water Resource Engineer, Caitlin Sporik, P.E., Project Engineer and Sean Crawford, P.E., Senior Project Manager at BayLand Consultants & Designers, Inc.  

Required Materials: Laptop with HEC-RAS 5.0.6 or most updated version downloaded

Provided Materials: Digital copies of HEC-RAS and terrain files for in-class examples and demonstrations

Learning Objectives:
1. Develop an understanding of how 2D hydraulic modeling can be used by practitioners during design to ensure that restored stream
channels and their adjacent floodplains are sustainable under a variety of flow and hydraulic conditions.
2.   Develop an understanding of the capabilities and limitations of the 2D HEC-RAS software.
3.   Learn how to approach and construct a 2D model by understanding the required inputs and variables, how they are developed, and
their relative impact on results.
4.   Work hands on with HEC-RAS through multiple in-class examples.
5.   Effectively view and analyze results within RAS Mapper.

Workshop Description:
Hydraulic modeling is an essential aspect of stream restoration assessment and design. It has traditionally been performed using one-dimensional (1D) models to estimate water surface elevations, map flood extents, calculate channel and floodplain hydraulic variables and analyze in-channel structures. The limitations of 1D models have produced mixed results, especially when modeling floodplains with lateral flow paths, braided and anastomosed systems, meander bends with significant super elevation, and tidally influenced reaches. The recent industry shift away from designs that utilize “hard” engineering techniques towards sustainable restoration methodologies that work with natural processes and improve ecosystems through increased floodplain connectivity has created demand for higher resolution models with increased accuracy and user flexibility. Two-dimensional hydraulic models meet these criteria by utilizing detailed computational meshes that can be modified by practitioners based on the size, scope and purpose of the model and/or goals of the project. The addition of 2D modeling capabilities by HEC-RAS has expanded the use and availability of these modeling techniques within the stream restoration industry. This workshop will focus on providing participants hands on experience developing a 2D model within HEC-RAS, including creating and manipulating a computational mesh, establishing boundary conditions, delineating roughness zones and developing all other inputs required to successfully run the model. Participants will then learn how to effectively view and analyze results with an emphasis on identifying areas of instability or concern. The workshop will conclude with the instructors providing several examples of how 2D modeling has been used to develop and modify restoration designs to ensure project stability and sustainability.