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Malaysia Water Research Journal
RUNOFF SIMULATIONS OF MIXED LAND USE OF SKUDAI
WATERSHED: SENSITIVE PARAMETERS
Khairul Anuar Mohamad 1 , Noor Baharim Hashim 2 , Ilya K.Othman 2
Research Officer, Coastal and Oceanography Research Centre, National Hydraulic
Research Institute of Malaysia, Lot 5377, Jalan Putra Permai, 43300 Seri Kembangan,
Selangor, Malaysia 1
Senior Lecturer, Department of Hydraulic and Hydrology, Faculty of Civil
Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia, 2
ABSTRACT
For the first time, Hydrological Simulation Program-Fortran (HSPF) was used to
study runoff simulation of mixed land use of Skudai watershed, the heaviest
polluted river in the district of Johor, Malaysia. The aim of this study is to examine
the sensitivity of HSPF parameters during runoff simulations for upstream of Skudai
watershed. The model was calibrated using data from November 2013-February
2014 and validated with observed data from March-May 2012 Different land use
types are shown to be sensitive to HSPF parameters especially to the index of
the mean infiltration capacity of the soil followed by the fraction of groundwater
inflow which will enter deep (inactive) groundwater, the upper zone nominal
storage and the lower zone nominal storage. Statistical analysis comprising of
coefficient of determination, Nash-Sutcliffe efficiency and the relative error
were used as evaluation indicators between simulated and observed runoff. By
examining the sensitivity analysis, it has been concluded INFILT is most sensitive
to runoff followed by the DEEPFR, UZSN and LZSN. Based on this study, HSPF is
capable to simulate runoff using hourly time-step for mixed land use in Malaysia.
Keywords: HSPF, Skudai Watershed, Statistical Analysis, HSPF Parameters, Mixed Land Use.
INTRODUCTION
Nowadays, simulation models of watershed hydrology have become one
of the principal aspects towards sustainable water resource development,
planning, and management. These models are influenced by various factors
such as spatial variability of soils, elevation, land used, weather and human
activities. With rapid development in some watersheds, increasing pollution
mainly from urban and agricultural lands has deteriorated the water quality in
rivers. Hence, simulation models that combine the use of long-term continuous
and storm event are needed in order to adequately manage watersheds and
address water quantity and quality problems. Hydrological Simulation Program-
Fortran (HSPF) is one of few models that combine the long-term continuous and
storm event.
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Institut Penyelidikan Hidraulik Kebangsaan Malaysia (NAHRIM)
National Hydraulic Institute of Malaysia (NAHRIM)