Civil Engineering ETDs

Publication Date

2-14-2014

Abstract

Physical and numerical models have been widely used to describe flooding patterns and to gain further understanding of river hydraulics around complex structures. Located on the Jemez River in New Mexico, the Jemez Weir stops the upstream progression of stream degradation and supports healthy upstream riparian vegetation. Localized bed scour began to occur just downstream of the Jemez Weir following construction. The United States Army Corps of Engineers (USACE) built the structure in 2003 and developed a HEC-RAS model in 2010 to re-evaluate the long term bed degradation downstream of the weir to assess structure stability. Additionally, the USACE estimated downstream localized scour depths using scour equations developed by Bormann and Julien (1991), Laursen and Flick (1983), and Lim (1992). After noting the structure needed additional modifications to prevent structural failure the USACE funded the development of a physical mobile bed model based on Froude Similitude to model scour patterns downstream of the Jemez Weir. This research takes the investigation one step further through the development and testing of a two-dimensional fixed bed model using the Bureau of Reclamations Sedimentation and River Hydraulics — Two Dimensional (SRH-2D) program. The two-dimensional fixed bed model was used to gain further understanding of flow interactions between the main channel and floodplain. The model was also utilized to develop a weir discharge rating curve for the Jemez Weir, and evaluate velocity and shear stress distributions around the Jemez Weir. SRH-2D results show a lower main channel discharge when compared to the HEC-RAS results around the Jemez Weir. Shear stress and velocity distributions agree with physical model results, and show localized scour will continue to threaten the structure unless modified. The results of this study can inform hydraulic modeling studies in similar settings because of the three different modeling techniques employed to address specific questions. Therefore, future case studies can use this study's results to guide modeling technique and help formulate an approach to answer a specific research question.'

Keywords

Two-dimensional model, Physical model, Hydraulics, Scour

Document Type

Thesis

Language

English

Degree Name

Civil Engineering

Level of Degree

Masters

Department Name

Civil Engineering

First Committee Member (Chair)

Eidson, Darrell

Second Committee Member

Stone, Mark

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