Wood Retention at Inclined Bar Screens: Effect of Wood Characteristics on Backwater Rise and Bedload Transport
Details
Serval ID
serval:BIB_2A5E04A2AB6E
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Wood Retention at Inclined Bar Screens: Effect of Wood Characteristics on Backwater Rise and Bedload Transport
Journal
Water
ISSN
2073-4441
Publication state
Published
Issued date
16/08/2021
Peer-reviewed
Oui
Volume
13
Number
16
Pages
2231
Language
english
Abstract
In forested mountain catchment areas, both bedload and large wood (LW) can be transported during ordinary flows. Retention structures such as sediment traps or racks are built to mitigate potential hazards downstream. Up to now, the design of these retention structures focuses on either LW or bedload. In addition, the majority of LW retention racks tend to retain both LW and bedload, while bedload transport continuity during ordinary flows is an important aspect to be considered in the design. Therefore, a series of flume experiments was conducted to study the effect of LW accumulations at an inclined bar screen with a bottom clearance on backwater rise and bedload transport. The main focus was put on testing different LW characteristics such as LW size, density, fine material, and shape (branches and rootwads), as well as a sequenced flood. The results demonstrated that a few logs (wood volume of ≈ 7 m3 prototype scale with a model scale factor of 30) are sufficient to reduce the bedload transport capacity to below 75% compared to the condition without LW. Fine material and smaller wood sizes further reduced bedload transport and increased backwater rise. In contrast, LW density and LW shape had a negligible effect. The test focusing on a sequenced flood highlighted the need for maintenance measures to avoid self-flushing of the bed material. The results of this study further indicate that an inclined bar screen may need to be adapted by considering LW characteristics in the design of the bottom clearance to enable bedload continuity during ordinary flows.
Keywords
bedload transport, flood protection, hydraulic structures, large wood (LW), river engineering
Web of science
Open Access
Yes
Create date
06/09/2021 9:41
Last modification date
07/12/2022 7:50