Effect of urban green space changes on the role of rainwater runoff reduction in Beijing, China

Abstract

h i g h l i g h t s• The green space area reduced by 199 km 2 and became fragmented from 2000 to 2010.• The annual runoff reduction volume ranged from 132 million m 3 to 198 million m 3 .• The rainwater runoff reduction rate decreased by 6% with the land cover changes.• The green space with larger LPI and AI is suitable for flooding risk reduction.a r t i c l e i n f o b s t r a c tThe effects of urban green spaces on stormwater runoff have increasingly attracted attention because of climate change and rapid urbanization conditions. This study investigates the spatial-temporal changes of urban green spaces in Beijing and estimates their effects on rainwater runoff reduction based on an empirical model. Results indicate that green spaces in Beijing decreased by 199 km 2 from 2000 to 2010 and that landscape patches became increasingly isolated and fragmented. The volume of rainwater runoff controlled by urban green spaces first increased and then decreased with the increase in summer rainfall. The runoff reduction rate continuously decreased from 23% in 2000 to 17% in 2010, which is mainly attributed to the composition changes in urban green spaces. In addition, an immense regional difference that is closely related to the changes in the largest patch and aggregation indices of urban green spaces are observed in different regions. This study recommends an optimal landscape pattern of urban green spaces for the planning and management of green spaces in highly urbanized areas.

Effects of Impervious Surface on the Spatial Distribution of Urban Waterlogging Risk Spots at Multiple Scales in Guangzhou, South China

“…Many landscape metrics have been proposed to measure the spatial pattern (i.e., area and configuration) of impervious surfaces [48][49][50]. In our study, eight landscape metrics that were used in previous studies and had a close association with hydrological responses [15,36,[51][52][53] were selected. The composition metrics include the percent of total impervious surface (%imp), building (%build), pavement (%pave) and the class area (Area_imp, Area_build, Area_pave).…”

“…Because %imp, %build and %pave had a strong collinearity with their area metrics at three grid scales, they were not further analyzed. The configuration metrics include Patch Density (PD), Edge Density (ED), Landscape Shape Index (LSI), Mean Euclidean Nearest Neighbor Distance (ENN_MN), the Patch Cohesion Index (Cohesion) and the Aggregation Index (AI) [53]. All of the landscape metrics (see Table 1) were calculated using Fragstats 4.1 at the class level [54].…”

Estimating the Effect of Urban Growth on Annual Runoff Volume Using GIS in the Erbil Sub-Basin of the Kurdistan Region of Iraq

“…The potential retention S is expressed in terms of the dimensionless curve number (CN) through the relationship S = 25, 400 CN − 254 (6) where S is expressed in mm, taking values from 0, when S → ∞, to 100, when S = 0. Furthermore, the initial abstraction rate is normally set to a constant value (λ = 0.2) in order for S to be the only parameter of the method.…”

“…The impact of urban growth is one of the significant land use changes affecting surface runoff within the catchment area [6]. Land use changes could have several influences on the hydrological cycle, water quality and quantity, which will result in flooding and droughts as well as changes in groundwater and river regimes in addition to an impact on runoff quality and quantity.…”

“…The nature of runoff and other hydrological characteristics is influenced by the process of urbanization, delivering pollutants to rivers and groundwater as well as increasing erosion. Urban growth includes the replacement of vegetated soils with impermeable surfaces; this process can impact the hydrologic processes, and the biogeochemical cycle at multiple scales [6,8,9]. Urban expansion also leads to the removal of trees and vegetation, causing a decrease in evapotranspiration.…”