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Geospatial modelling of watershed peak flood discharge in Selangor, Malaysia.

Cheah, Ryan; Billa, Lawal; Chan, Andy; Teo, Fang Yenn; Pradhan, Biswajeet; Alamri, Abdullah M.


Ryan Cheah

Lawal Billa

Fang Yenn Teo

Biswajeet Pradhan

Abdullah M. Alamri


Conservative peak flood discharge estimation methods such as the rational method do not take into account the soil infiltration of the precipitation, thus leading to inaccurate estimations of peak discharges during storm events. The accuracy of estimated peak flood discharge is crucial in designing a drainage system that has the capacity to channel runoffs during a storm event, especially cloudbursts and in the analysis of flood prevention and mitigation. The aim of this study was to model the peak flood discharges of each sub-watershed in Selangor using a geographic information system (GIS). The geospatial modelling integrated the watershed terrain model, the developed Soil Conservation Service Curve Cumber (SCS-CN) and precipitation to develop an equation for estimation of peak flood discharge. Hydrological Engineering Center-Hydrological Modeling System (HEC-HMS) was used again to simulate the rainfall-runoff based on the Clark-unit hydrograph to validate the modelled estimation of peak flood discharge. The estimated peak flood discharge showed a coefficient of determination, r2 of 0.9445, when compared with the runoff simulation of the Clark-unit hydrograph. Both the results of the geospatial modelling and the developed equation suggest that the peak flood discharge of a sub-watershed during a storm event has a positive relationship with the watershed area, precipitation and Curve Number (CN), which takes into account the soil bulk density and land-use of the studied area, Selangor in Malaysia. The findings of the study present a comparable and holistic approach to the estimation of peak flood discharge in a watershed which can be in the absence of a hydrodynamic simulation model.


CHEAH, R., BILLA, L., CHAN, A., TEO, F.Y., PRADHAN, B. and ALAMRI, A.M. 2019. Geospatial modelling of watershed peak flood discharge in Selangor, Malaysia. Water [online], 11(12), article 2490. Available from:

Journal Article Type Article
Acceptance Date Nov 21, 2019
Online Publication Date Nov 26, 2019
Publication Date Dec 31, 2019
Deposit Date Apr 7, 2023
Publicly Available Date Apr 11, 2023
Journal Water
Electronic ISSN 2073-4441
Publisher MDPI
Peer Reviewed Peer Reviewed
Volume 11
Issue 12
Article Number 2490
Keywords GIS; Watershed precipitation; Curve number; Peak flood discharge; Selangor; Malaysia
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CHEAH 2019 Geospatial modelling (VOR) (1.8 Mb)

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Copyright Statement
© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (

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