Improving Flows in Misaligned Culverts

Rick Jaeger,Katharina Tondera,Carolyn Jacobs,Neil Tindale

doi:10.3390/w11091932

Rick Jaeger, Katharina Tondera + Show 2 more

Open Access

https://doi.org/10.3390/w11091932

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Journal: Water	Publication Date: Sep 16, 2019
Citations: 1	License type: CC BY 4.0

Affiliation: University of the Sunshine Coast, IMT Atlantique

Abstract

This study investigated different approaches to optimize flows in misaligned culverts. Structures aligned with the natural stream are always preferred, as misalignments cause a change of direction at the culvert inlet associated with lower performance and sedimentation and erosion problems. This optimal positioning can cause high financial costs and a flow optimization minimizing the associated problems could be a viable alternative. In this study, we used computational fluid dynamics analysis to evaluate the flow in 44 different scenarios with misalignment angles ranging from 0 ∘ –90 ∘ . It was found that smooth transitions towards the narrowest point in the stream (culvert) were possible for any degree of misalignment resulting in improved, uniform velocity distributions and less turbulence. An experimental setup was able to confirm the possible flow improvements. The proposed approach of flow redirection can lower construction costs and gives planners and designers more flexibility as tailored reinforcement and redesign of the stream embankment can be used as an alternative to costly creek alignments.

Highlights

Perpendicular crossings between transport infrastructure and natural streams are favored when installing new culverts, but this is not always possible as natural creeks meander through the landscape.Maintaining a perpendicular intersection and not aligning the culvert with the main flow direction leads to reduced flows, higher blockage risks [1,2,3], and sedimentation and erosion [4,5,6]
There is a wide range of possible forms for misaligned culverts with angles varying between 0o to
This research focuses on exploring the flows in a layout where the culvert inlet sits centered in the natural stream bed and the culvert width is a third of the streams width

Summary

Introduction

Perpendicular crossings between transport infrastructure and natural streams are favored when installing new culverts, but this is not always possible as natural creeks meander through the landscape.Maintaining a perpendicular intersection and not aligning the culvert with the main flow direction leads to reduced flows, higher blockage risks [1,2,3], and sedimentation and erosion [4,5,6]. Perpendicular crossings between transport infrastructure and natural streams are favored when installing new culverts, but this is not always possible as natural creeks meander through the landscape. Culvert pipes not perpendicular to the transport infrastructure are called skewed barrels. They allow an alignment of the culvert with the stream, but these designs exceed the minimum length necessary as they do not cross in the shortest possible way. This causes higher costs and often makes different inlet designs necessary as well. Culvert headwalls are adjusted to the embankment rather than normal to the pipe

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