The Rainwater Interception Process and Capacity of Urban Tree Organs in Shanghai

Abstract

The process of rainwater interception by tree organs is crucial in mitigating the impact of intense rainfall on urban drainage systems, particularly in the context of climate change. For this study, we selected ten commonly found tree species in Shanghai, and the main parts of trees, including their leaves, branches, and bark, were collected to analyze their ability to intercept rainwater. The optimized Artificial Rainfall Simulation System (ARSS) was applied to simulate rainfall. The time-changing process of rainwater interception in three organs was measured during a 180 min rainfall event under four different rainfall intensities (4, 8, 12, and 16 mm/h, respectively). Process models of rainwater interception in different organs were fitted with adsorption kinetic equations. The rainwater interception process of tree organs complied with the quasi second-order adsorption kinetic equation. The rainwater interception capacity values of the leaves, branches, and bark of the ten urban tree species ranged from 0.05 to 0.34 mm, 0.13 to 0.24 mm, and 0.29 to 1.22 mm, respectively. The rainwater interception capacity values of the three organs significantly differ (p < 0.05). The results of this study reveal that bark exhibits the greatest rainwater interception ability. Coniferous tree species have a greater ability to intercept rainwater than broad-leaved tree species. There are also differences in the rainwater interception ability of trees in urban and natural areas.