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Turbulence and Bed Load Transport in Channels With Randomly Distributed Emergent Patches of Model Vegetation
Author(s) -
Shan Yuqi,
Zhao Tian,
Liu Chao,
Nepf Heidi
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl087055
Subject(s) - turbulence , vegetation (pathology) , sediment transport , sediment , channel (broadcasting) , hydrology (agriculture) , scale (ratio) , environmental science , geology , open channel flow , bed load , soil science , geomorphology , mechanics , geotechnical engineering , geography , physics , medicine , cartography , engineering , pathology , electrical engineering
Abstract Laboratory experiments explored the impact of vegetation patchiness on channel‐averaged turbulence and sediment transport. Stems were clustered into 16 randomly distributed circular patches of decreasing diameter. For the same channel velocity, the sediment transport increased with total stem number but decreased as stems were clustered into smaller patch diameters, occupying a smaller fraction of the bed area. The channel‐averaged turbulence, which also declined with increased clustering, was shown to be a good predictor for sediment transport at the channel scale. Previous models for uniform vegetation were adapted to predict both the channel‐averaged turbulence and sediment transport as a function of the total number of stems and degree of clustering, represented by the fraction of bed covered by patches. This provides a way for numerical modelers to represent the impact of subgrid‐scale vegetation patchiness on sediment transport.