Affiliation:
1. The National Key Laboratory of Water Disaster Prevention Hohai University Nanjing China
2. Key Laboratory of Hydrologic‐Cycle and Hydrodynamic‐System of Ministry of Water Resources Hohai University Nanjing China
3. Department of Civil and Environmental Engineering The University of Auckland Auckland New Zealand
4. Department of Structures for Engineering and Architecture University of Napoli Federico II Napoli Italy
Abstract
AbstractFallen trees enter the adjacent stream and are carried away downstream by the current. As the stream joins another one, the complex hydrodynamics near their confluence make the movement of wood hard to predict. These woods may accumulate near the confluence resulting in backwater and subsequent potential flooding. A laboratory study was conducted to investigate the movement and accumulation behavior of individual pieces of wood near the confluence. The characteristics of wood (i.e., the length, diameter, and density) and the hydraulic conditions (i.e., the discharge ratio and the release distance) were varied in this investigation. It was found that the wooden pieces released from the tributary got occasionally trapped in the flow separation zone of the confluence, whereupon they were mainly trapped by a clockwise vortex and continued to stay driven by a reverse cluster of currents within this zone. The accumulation probability of wood was mainly related to its length, the discharge ratio and the release distance. The effect of wood diameter and density within the tested parameters was negligible. The probability increased with an increase in the discharge ratio as well as a decrease in the release distance. The longer pieces had a higher probability of being trapped, whereas for those exceeding some critical value, the probability was nearly the same, or dropped sharply. A generalized model for wood accumulation near the confluence was developed for practical application. These findings carry significant implications for river management, particularly in preventing the risk of flooding caused by wood blockage.
Funder
National Key Research and Development Program of China
National Natural Science Foundation of China
Fundamental Research Funds for the Central Universities
Higher Education Discipline Innovation Project
Publisher
American Geophysical Union (AGU)
Cited by
2 articles.
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