Bed morphology adjustment under the impact of a near-bank emergent model vegetation patch

Abstract

ABSTRACTThis paper investigated spatial characteristics of bed morphology around a near-bank emergent vegetation patch. Experimental results showed that patch length and density impacted the spatial scale, orientation and type of pool-bar morphology around the patch. Adjacent to the patch, the pool onset lowest location tended to move upstream as patch length and density increased, quantitatively described by a power function involving the two factors; the transverse bed topography along the pool was described by a two-zone scaling model, providing prediction models for the pool morphology, particularly for narrow urban channels. Moreover, we identified, in the patch wake, two types of bars formed meditated by patch length. Short-point and elongated bars formed under short and long patches, respectively, attributed to different mechanisms of flow–sediment-patch interaction, offering new insights into wake depositional trends and streamwise vegetation succession during different vegetation growth stages. The gained knowledge is useful for vegetation-based urban channel restoration.KEYWORDS: Flow–sediment–vegetation interactionnear-bank vegetation successionpool-bar morphologysecondary flowssimilarity in bed topography Supplemental dataSupplemental data for this article can be accessed online at https://doi.org/10.1080/00221686.2023.2241844.Data availabilityMost figures can be generated from data deposited at https://doi.org/10.5281/zenodo.4993413Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis research was partially supported by the National Natural Science Foundation of China (nos. 52239006 and 51909178), the Fundamental Research Funds for the Central Universities, Sichuan University (2020SCU12064) and the RGC project (Polyu 152743/16E), Hong Kong; The research project from the Hong Kong Polytechnic University; CRSRI Open Research Program.