Bulk Drag Predictions of Riparian Arundo donax Stands through UAV-Acquired Multispectral Images

Abstract

Estimating the main hydrodynamic features of real vegetated water bodies is crucial to assure a balance between their hydraulic conveyance and environmental quality. Riparian vegetation stands have a high impact on vegetated channels. The present work has the aim to integrate riparian vegetation’s reflectance indices and hydrodynamics of real vegetated water flows to assess the impact of riparian vegetation morphometry on bulk drag coefficients distribution along an abandoned vegetated drainage channel fully covered by 9–10 m high Arundo donax (commonly known as giant reed) stands, starting from flow average velocities measurements at 30 cross-sections identified along the channel. A map of riparian vegetation cover was obtained through digital processing of Unnamed Aerial Vehicle (UAV)-acquired multispectral images, which represent a fast way to observe riparian plants’ traits in hardly accessible areas such as vegetated water bodies in natural conditions. In this study, the portion of riparian plants effectively interacting with flow was expressed in terms of ground-based Leaf Area Index measurements (LAI), which easily related to UAV-based Normalized Difference Vegetation Index (NDVI). The comparative analysis between Arundo donax stands NDVI and LAI map enabled the analysis of the impact of UAV-acquired multispectral imagery on bulk drag predictions along the vegetated drainage channel.

Hydraulic Efficiency of Green-Blue Flood Control Scenarios for Vegetated Rivers: 1D and 2D Unsteady Simulations

“…value compatible with span height at "Bridge B" cross-section, equal to 4.50 m (See Table 2). As suggested by many previous analytical and modeling studies on the real-scale ecohydrodynamic response of common reed stands [11,40,41], the vertical distribution of plants' green leaf volumes is very similar on the whole reed height, with negligible LAI values in the first 0.10-0.15 m from the ground [38,41]. Thus, LAI is rigorously the same as plant area index (PAI) in the case of common reed beds, with PAI quantitatively obtained by dividing the total stems and leaves areas (in m 2 ) within the examined riverine plants' height (in m 2 ) and the projected ground area (in m 2 ), both measured in dedicated ecohydraulic field campaigns [42,43].…”

Evaluation of Water Circulation by Modeling: An Example of Nonpoint Source Management in the Yeongsan River Watershed

“…In addition, it is necessary to manage urban areas with a large impervious area by designating them as nonpoint pollution management areas and to prevent indiscriminate urban development and damage to forests and fields. Through the results of [35,36], flood occurrence in urban areas can be analyzed through the flow of fluids according to changes in rivers and waterways and changes in trees in the river ecosystem. For new cities, it is necessary to introduce a water circulation system that can improve rainwater penetration and recharge by introducing the LID technique and activating preemptive water circulation.…”

High Light Intensity from Blue-Red LEDs Enhance Photosynthetic Performance, Plant Growth, and Optical Properties of Red Lettuce in Controlled Environment

“…However, the light spectrum and light intensity can affect leaf pigment composition and leaf spectral absorbance differently in crops. Leaf spectral analysis is a widely used technique for nondestructive monitoring of plant health status and pigment composition [10][11][12]. Excess of light in terms of intensity can be harmful to photosystems and induce plants to synthesise different antioxidant compounds and non-photosynthetic pigments to mitigate the excess of light and reactive oxygen species (ROS) scavenging activity, affecting photochemical functions.…”