Simulating the Hydrological Impact of Green Roof Use and an Increase in Green Areas in an Urban Catchment with i-Tree: A Case Study with the Town of Fontibón in Bogotá, Colombia

Abstract

Urbanization has produced various social, environmental, and hydrological impacts, such as reduced biodiversity, increased urban temperatures, ecosystem degradation, air and water pollution, changes to hydrological processes, groundwater recharge alterations, increased prevalence of floods, vegetation removal, and potential increases in unstable soils. Finding solutions to mitigate the impacts of urbanization is of vital importance in the development and planning of cities, and particularly so for developing countries. One strategy gaining momentum is the use of green roofs and larger green areas (greater green cover under trees, with the purpose of increasing the permeable area) for runoff control. In this study, a simulation was carried out using the i-Tree Hydro software that involved the urban basin in the Fontibón area of Bogotá, Colombia, with the aim of observing the hydrological benefits of trees, green areas, and permeable zones. Five scenarios were proposed in which green roof coverage was implemented (20% and 50% increases in green areas in Scenarios 1 and 2), coverage under existing trees was enhanced (50% and 100% increase in Scenarios 4 and 5), and finally a complete removal of green zones in Fontibón was simulated (Scenario 3). The town is relatively susceptible to a reduction in its existing green areas, with an increase in total flow of more than 50% for one scenario considered. Thus, an increase in the permeable coverage under trees (50% and 100% increased coverage under existing trees) provided the best strategy for mitigating the impacts of urbanization by reducing the total, maximum, and average impervious flow by 3%, 4%, and 8%, respectively. Finally, an increase in permeable zones corresponding to plants was proposed via the implementation of green roofs. However, this strategy showed a response to the reduction in the lowest total flow at 1%. runoff processes [12], cause surface water quality and runoff degradation [13], and increase the peak during precipitation events [14], which can cause the overflow of storm drains or combined sewers [15]. Flows in urban basins may exceed those in less urbanized or non-urbanized basins by between 30% and 100% [16].Permeable zones and green structures in urban environments are fundamental components of the design and planning for sustainable cities. Various investigations have determined the role that these structures play in mitigating heat island effects, pollutant removal from air and runoff water, their influence on the carbon cycle, and greenhouse gas reduction [17,18]. Vegetation cover is necessary to avoid oversaturating the processes taking place within a water system (e.g., infiltration, runoff, evapotranspiration). Urban green areas are also used as a strategy to prevent flooding since they increase the permeable surface within basins [19,20], on the other hand, some research has shown that the green roof help to reduce the annual runoff volume by 40% and peak discharge by 15% [21]. The World Health Organization has therefore established as a...

Green Areas and Climate Change Adaptation in a Urban Environment: The Case Study of “Le Vallere” Park (Turin, Italy)

“…These results are consistent with the findings of those of previous studies, such as [47], where the reduction capacity of green infrastructure on storm water runoff was investigated with a focus on urban hydrological processes. Furthermore, refer to [48] for any comparisons with other case studies, where different examples implementing i-Tree Hydro are reported and grouped in terms of country and type of application.…”

Hydrological Effects of Urban Green Space on Stormwater Runoff Reduction in Luohe, China

“…The i-Tree Hydro model is a peer-reviewed, free desktop application that is widely used to probe the relationship between urban hydrological balance and vegetation [29][30][31][32][33][34][35][36][37][38][39]. For example, Kirnbauer et al (2013) quantified the canopy interception potential and evaporation by an i-Tree Hydro model to decide how to use vacant and underutilized land productively in Hamilton, Canada [31].…”

“…Lefrançois (2015) utilized the model to quantify the effect of surface cover change on the sewershed at a community scale in Vancouver, Canada [32]. Finally, Bautista and Peña-Guzmán (2019) simulated the hydrological impact of green roofs and increasing green areas in Fontibón Town, Colombia [39]. Thus, the i-Tree Hydro model should be suitable to estimate the hydrological benefits of UGS in this research.…”

Evaluating the Impact of Urban Stormwater Runoff by Street Tree Canopy

“…)가 2000년대부터 진행되어 왔으며 미국 농림부 (The United States Department of Agriculture, USDA)에서는 가로수에 의한 수량, 수질 및 대기 오염에 관한 편익을 평가하 기 위하여 i-Tree 프로그램을 개발하여 적용 (Nowak et al, 2008;G.W. Kim et al, 2015;Bautista and Peña-Guzmán, 2019)…”