Evaluation of the PG method for modeling unsteady flows in complex bathymetries

Abstract

The performance graph (PG) hydraulic routing method has been shown to be accurate, numerically efficient, and robust for unsteady flow routing. However, up to present, the PGs are constructed using one-dimensional (1D) steady flow models only, which are often questioned when simulating flows through complex bathymetries. This paper investigates whether the PG method can still be used when utilizing two-dimensional (2D) models for the construction of PGs. The test case is a stretch around an island in the Fraser River in British Columbia. The results show that the PG method is still applicable when utilizing a 2D steady flow model. The results also show that once the PGs are constructed, the PG routing method (1D and 2D) is computationally more efficient than the unsteady HEC-RAS model and can be several orders of magnitude faster than TELEMAC-2D.

Keywords:

• complex river bathymetry
• hydraulic routing
• numerical modeling
• performance graph
• unsteady flow
• two-dimensional modeling

Acknowledgments

The authors would also like to thank NHC, Vancouver, B.C., for providing the bathymetric data used for this study. Last but not least, we thank the editor and two anonymous reviewers for their constructive comments, which helped us to improve the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Arturo S. Leon  http://orcid.org/0000-0002-7117-7351

Additional information

Funding

The authors gratefully acknowledge the financial support of the Bonneville Power Administration of the U.S. Department of Energy under award number TIP#258.

Notes on contributors

Arturo S. Leon

Arturo S. Leon earned his Ph.D. in Civil and Environmental Engineering from the University of Illinois at Urbana-Champaign in 2007. Since the Fall of 2016, Arturo is working as an Associate Professor at the University of Houston. The main research interests of Arturo are on the areas of urban hydrology, flood control, stormwater management, and optimal water resources decision making. Arturo developed more than 10 computer models for various applications. For instance, his open-source Illinois Transient Model (ITM) (http://www2.egr.uh.edu/~aleon3/ITM.htm) has been widely used for the transient and non-transient analysis of combined sewer systems in US cities such as Chicago, Cleveland, Pittsburgh, San Francisco, and Dallas, and worldwide in countries such as Switzerland, France, Germany and New Zealand. His model OSU-OUU (http://www2.egr.uh.edu/~aleon3/Projects/BPA/OSU_OUU_Website/index.html) is currently enabling to make real-time optimal decisions of water use in the Columbia River system that involves five States [OR, ID, WA, MT, CA] and Canada.

Christopher Gifford-Miears

Chris earned his Master of Science degree in Civil Engineering from Oregon State University in 2014. Since the Spring of 2014, Chris has worked as a hydrology and hydraulics civil engineer at Montgomery, Watson, and Harza (MWH) Global engineering consultants, now part of Stantec. During his graduate studies, his research interests included computational hydraulics, uncertainty propagation in river systems, and fish passage modeling. His main responsibilities for MWH include hydrologic investigations, hydraulic design, flood inundation studies, GIS data management and spatial analyses, dam breach modeling, tailing dam failure analyses, design optimization and visualization.