Modeling of soft bedrock channel evolution with a coupled modified bank stability and bedrock erosion model

Kuowei Wu, Keh-Chia Yeh, Yong G. Lai

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Streambank erosion of soft bedrock channel can be an important form of channel evolution in severe soft bedrock erosion environments. It should be accounted for in geomorphic studies, river restoration, and channel stability engineering projects. Recently, some one-dimensional and two-dimensional flow and mobile-bed numerical models have coupled bedrock erosion mechanism to predict the channel evolution and become useful tools for channel stability evaluation in response to stream modifications. Most, however, either ignore streambank erosion or implement only alluvial lateral erosion methods. In this study, a coupled bedrock erosion model is developed that incorporates a modified process-based bank stability model for lateral retreating and bedrock erosion mechanism for vertical scour within a recently developed two-dimensional geo-fluvial model, SRH-2D, to predict soft bedrock channel evolution. A coupling procedure that emphasizes solution robustness as well as ease-of-use is developed and described. The coupled model is then verified by applying it to the soft bedrock channel evolution at the immediately downstream river reach of Chi-Chi weir, Cho-Shui River, Taiwan. Comparisons are made between the predicted and measured data, as well as results of our previous bedrock erosion modeling study, which considered only vertical erosion mechanism with hydraulic and abrasive scour. On one hand, this study demonstrates that the use of two-dimensional coupled models leads to promising improvements over that abrasive and hydraulic erosion models. It therefore encourages the use of coupled bedrock erosion models in channel evolution predictions. On the other hand, the study also identifies future research needs in order to improve numerical modeling of complex streams. The developed model is shown to be robust and easy to apply with simple field investigation; it may be used as a practical tool to predict soft bedrock channel evolution caused by artificial and geotechnical processes.

Original languageEnglish
Title of host publicationScour and Erosion IX - Proceedings of the 9th International Conference on Scour and Erosion, ICSE 2018
EditorsYeh Keh-Chia
PublisherCRC Press/Balkema
Number of pages1
ISBN (Print)9780367074678
StatePublished - 1 Jan 2019
Event9th International Conference on Scour and Erosion, ICSE 2018 - Taipei, Taiwan
Duration: 5 Nov 20188 Nov 2018

Publication series

NameScour and Erosion IX - Proceedings of the 9th International Conference on Scour and Erosion, ICSE 2018

Conference

Conference9th International Conference on Scour and Erosion, ICSE 2018
CountryTaiwan
CityTaipei
Period5/11/188/11/18

Fingerprint Dive into the research topics of 'Modeling of soft bedrock channel evolution with a coupled modified bank stability and bedrock erosion model'. Together they form a unique fingerprint.

Cite this