Detailed Quantification of the Reduction Effect of Roof Runoff by Low Impact Development Practices

Pu Zhang,Guoyuan Wei,Xiaoyue Zhang,Zhenyao Shen,Xiaoshu Hou,Lei Chen

doi:10.3390/w12030795

Pu Zhang, Guoyuan Wei + Show 4 more

Open Access

https://doi.org/10.3390/w12030795

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Journal: Water	Publication Date: Mar 12, 2020
Citations: 10	License type: CC BY 4.0

Affiliation: Beijing Normal University, Hebei University of Engineering

Abstract

Low impact development (LID) has been widely applied to mitigate urban rainwater problems since the 1990s. However, the effect of LID practices has seldom been evaluated in detail. In this study, the effect of individual and combined LID practices on the reduction of roof runoff are specifically quantified considering the hydrological relationship between LID at the building scale and the campus scale at Beijing Normal University (BNU). The results show that individual and combined LID practices effectively reduce roof runoff for all types of rainfall and for rainfall with return periods from 0.5 to 50 years at the building scale. Combination scenarios maintain good performance with fewer areas of composed LID. Most values for the effect of combination scenarios are between the effects of composed LID. To achieve the highest cost efficiency, low elevation greenbelts should be the first choice, and green roofs should only be selected when low elevation greenbelts and rain barrels cannot be implemented. At the campus scale, individual and combined LID practices effectively reduce the outflow from and the overflow in the campus and combination scenarios have the best reduction performance. This study provides an important reference for urban water management and LID related decision making.

Highlights

In recent years, urban floods have become a frequent occurrence worldwide due to rapid urbanization and climate change [1,2,3]
Low impact development (LID), as one urban storm water management approach, has been proposed and widely applied to mitigate this problem since the 1990s [6]. It was adopted as an important strategy for managing urban runoff in the sponge city policy proposed by the Chinese government in 2013 [7]
These results indicate that the performance of the storm water management model (SWMM) green roof roofmodule moduleisisacceptable acceptable a time of 5 minutes at the building scaleasasthe long as the of at aattime scalescale of 5 minutes and atand the building scale as long parameters parameters of roof the green roof are appropriately set

Summary

Introduction

Urban floods have become a frequent occurrence worldwide due to rapid urbanization and climate change [1,2,3] Such floods have already presented great risks to human safety and economic losses to cities worldwide [4,5]. LID, as one urban storm water management approach, has been proposed and widely applied to mitigate this problem since the 1990s [6]. It was adopted as an important strategy for managing urban runoff in the sponge city policy proposed by the Chinese government in 2013 [7]. Redfern et al [9] suggested that

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