Effects of Green Infrastructure for Resilient Cities
at the Catchment Scale in Urban Area
Chaeyoung Bae1, Dong Kun Lee1,21Interdisciplinary Program in Landscape Architecture, 2Department of Landscape Architecture and Rural System Engineering

Result 2. Direction of GI application for resilient cities

Abstract
This study set up catchment-scale sites located at the boundary where rainwater is treated in anurban area and evaluated the impacts of GI(Green Infrastructure) using the SWMM(Storm Water
Management Model) based on actual flood events during the wet season.
The first result showed that GI could reduce the runoff volume, peak flow, and inundation volume
compared with conventional development. This study also used and demonstrated the implicationsof sensitivity testing and model updating to increase the correlation between the real system andthe modeled site. In second result, considering the intervention between the areas that contributethe most to surface flooding and potential flood hazard highest, we explored the areas where theGI application was most appropriate in the future.

< Inundation trace map >lowmediumhigh

Impact :Flood Hazard Areas(potential flood hazard highest)

Process and method of study

Calculate of conduit effluent
Simulation of runoff (SWMM)

Result analysis Tools
Error function

Extracting maximum
applicable area for GI
Parameter control

Catchment description
1. Input of overland data
2. Precipitation data (2011 flood event)

Areas contributing
the mostto surface flooding

Surface flow volume
before and after GI
Compare the effect of GI
with pipe extension

Characterize
the spatial flood
problemNO

YES

Source : Flood Source Areas(contributing the most to surface flooding)Classification of infrastructure systems
according to potential opportunities(Vercruysse et al., 2019)

Result 1. Effects of GI on flood events• (Parameter sensitivity test and model updating)Manning's N value of pervious surface which is themost sensitive parameter was adjusted for site within
the respective range to approximate the inundated
area based on the inundation trace map• (Effect of GI) GI did not affect the occurrence offlooding, but the flood reduction effect was 2–5 times
higher than that of runoff. The results showed that thesame effect could be obtained by enlarging the conduit
cross-sectional area of the whole site by 11–13%

lowmediumhigh• (Source) Runoff contributions of each sub-catchment is analyzed
by repeatedly executing a precipitation-omitting model• (Impact) The potential hazard of each sub-catchment isanalyzed relatively by using inundation trace map► The source and impact areas of the flood were distinguished.
And given the interoperability between them, it is possible todetermine which point GI application would be the mosteffective compared to current land use. This part is handled by
the method of Vercruysset al.(2019)< The area of opportunity in rainwater
harvesting on the current land cover map >Summary and future research< Sensitivity test of input variables for internal inflow >• (GI application direction for resilient city) Based on result 2, information on which areas are
currently being utilized and which areas should be improved can be provided for future urban
regeneration planning• (Pont of improvement) It Requires a high resolution grid unit evaluation and potential hazard data
to replace flooding events

Acknowledgements
This work was conducted with the support of the Korea Environment Industry & Technology
Institute (KEITI) through its Urban Ecological Health Promotion Technology Development Project,and funded by the Korea Ministry of Environment (MOE). (2019002760002)< Hydrograph results before and after GI >< Flood volume modeling results by enlargement percentageof conduit’s cross-sectional area >The 26th AIM International Workshop
National Institute for Environmental Studies (Online), 3rd Sep. – 4th Sep. 2020