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Updated: May 9, 2026

Design and Construction of an Urban Runoff Research Facility
Published on: August 8, 2014
Quantitative analysis on the urban flood mitigation effect by the extensive green roof system
1KIST (Korea Institute of Science and Technology), Gangneung Institute, Gangnueng 210-340, South Korea. juyounglee@snu.ac.kr
Abstract:
Extensive green-roof systems are expected to have a synergetic effect in mitigating urban runoff, decreasing temperature and supplying water to a building. Mitigation of runoff through rainwater retention requires the effective design of a green-roof catchment. This study identified how to improve building runoff mitigation through quantitative analysis of an extensive green-roof system. Quantitative analysis of green-roof runoff characteristics indicated that the extensive green roof has a high water-retaining capacity response to rainfall of less than 20 mm/h. As the rainfall intensity increased, the water-retaining capacity decreased. The catchment efficiency of an extensive green roof ranged from 0.44 to 0.52, indicating reduced runoff comparing with efficiency of 0.9 for a concrete roof. Therefore, extensive green roofs are an effective storm water best-management practice and the proposed parameters can be applied to an algorithm for rainwater-harvesting tank design.
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