Laboratory Analysis of Identifying Influence of Vegetation, Bed Type, River Regulation on Microplastic Transportation in Open Channels.

Abstract

The intricate dynamics of microplastic transport in open channels involve factors such as water flow velocity, turbulence, water depth, sediment characteristics, particle size, and channel morphology. In this context, a laboratory study was conducted to explore the influence of different factors on microplastic transport, including vegetation patterns, discharge rates, microplastic types, bed type, and the impact of dam structures. The experiment was done using three different microplastics ranging their densities from 910 to 1350 kgm-3. Hydrilla was used as vegetation in three different patterns along the open channel bed to find the influence of vegetation density and pattern. The effect of different bed types and two dam structures were used representing river regulation to monitor microplastic transportation. Overall microplastic transportation was directly correlated with discharge under all conditions except for denser microplastics in gravel bed condition. There was a significant influence of vegetation pattern rather than the vegetation density in retaining microplastics. The study showed that dam structures allowing seepage flow was more effective in retaining microplastic rather than dams allowing overflow. This study paves the way to understand the inter relationships between different hydrological and morphological factors affecting microplastic transportation in open channels.