The role of trees in urban stormwater management

Abstract

Urban impervious surfaces convert precipitation to stormwater runoff, which causes water quality and quantity problems. While traditional stormwater management has relied on gray infrastructure such as piped conveyances to collect and convey stormwater to wastewater treatment facilities or into surface waters, cities are exploring green infrastructure to manage stormwater at its source. Decentralized green infrastructure leverages the capabilities of soil and vegetation to infiltrate, redistribute, and otherwise store stormwater volume, with the potential to realize ancillary environmental, social, and economic benefits. To date, green infrastructure science and practice have largely focused on infiltration-based technologies that include rain gardens, bioswales, and permeable pavements. However, a narrow focus on infiltration overlooks other losses from the hydrologic cycle, and we propose that arboriculturethe cultivation of trees and other woody plantsdeserves additional consideration as a stormwater control measure. Trees interact with the urban hydrologic cycle by intercepting incoming precipitation, removing water from the soil via transpiration, enhancing infiltration, and bolstering the performance of other green infrastructure technologies. However, many of these interactions are inadequately understood, particularly at spatial and temporal scales relevant to stormwater management. As such, the reliable use of trees for stormwater control depends on improved understanding of how and to what extent trees interact with stormwater, and the context-specific consideration of optimal arboricultural practices and institutional frameworks to maximize the stormwater benefits trees can provide.

Evaluating the influence of design strategies and meteorological factors on tree transpiration in bioretention suspended pavement practices

“…In addition to improving water quality through biogeochemical treatment processes, a key objective of bioretention practices is the reduction of run-off volumes and peak flow rates to more closely mimic predevelopment hydrology (Hunt, Davis, & Traver, 2012). Second, stormwater can be lost via soil evaporation and transpiration by vegetation, commonly combined as evapotranspiration (ET; Berland et al, 2017). Volume reduction is primarily achieved through two mechanisms.…”

The benefits of trees for livable and sustainable communities

“…Trees are considered "decentralized green infrastructure" and can be important tools for managing water, especially in an urban ecosystem (Berland et al, 2017). Water runoff is a serious issue in the city environment, as runoff can increase the exposure to pollution and cause property damage (Braden & Johnston, 2004).…”

“…Water runoff is a serious issue in the city environment, as runoff can increase the exposure to pollution and cause property damage (Braden & Johnston, 2004). Trees can help reduce and intercept stormwater and improve the quality of runoff water (Berland et al, 2017;Bolund & Hunhammar, 1999;Brack, 2002;Livesley, McPherson, & Calfapietra, 2016;Scharenbroch, Morgenroth, & Maule, 2016). With less contact on impervious surfaces, stormwater is cooler and has fewer pollutants when it enters local waterways and water-related ecosystems (Schwab, 2009).…”

Performances of Urban Tree Species under Disturbances in 120 Cities in China

“…Urban forests can generate ecosystem services that are essential for urban residents' wellbeing, such as removal of air pollutants [1], reduction of urban floods [2], alleviation of urban heat islands [3], and provision of recreational opportunities [4]. Because of these important benefits, cities worldwide are investing resources to maintain existing urban forests and create new ones.…”