mag

Malaysia Water Research Journal
The HSPF uses several parameters to select sensitivity analysis for hydrologic
simulation which can be defined in EPA BASINS Technical Note 6 (USEPA, 2000).
The time step of simulation used was 1 hour and was carried out within less
than 3 months. Modelled parameters affect both water balance and flow by
distributing capacity of water between surface runoff, interflow, baseflow and
deep groundwater. Table 2 summarizes the final values of hydrologic pervious
land parameters and Table 3 summarizes values of hydrologic impervious land
parameters that were adjusted during calibration and validation process. These
values fall within the range of values as stated at typical range below.
Table 2: Parameter values for hydrologic simulation for the Skudai river
watershed (Pervious Land)
Parameter
Calibrated
Value
Typical
Range
LZSN The lower zone nominal storage 6.2 3.0-8.0
INFILT
LSUR
SLSUR
KVARY
AGWRC
INFEXP
INFILD
DEEPFR
BASETP
AGWETP
The index to the mean infiltration
capacity of the soil
The length of the assumed overland
flow plane
The slope of the overland flow
plane
The parameter which affects the
behavior of groundwater recession
flow
The basic groundwater recession
rate if KVARY is zero and there is no
inflow to groundwater
The exponent in the infiltration
equation
The ratio between the maximum
and mean infiltration capacities
over the pervious land segments
The fraction of groundwater inflow
which will enter deep (inactive)
groundwater
The fraction of remaining potential
E-T
The fraction of remaining potential
E-T
0.24 0.01-0.25
600 200-500
0.078-0.09 0.01-0.15
1 0.0-3.0
0.93-0.99 0.92-0.99
2 2
2 2
0.2 0.0-0.2
0.05 0.0-0.05
0.05 0.0-0.05
Institut Penyelidikan Hidraulik Kebangsaan Malaysia (NAHRIM)
125
National Hydraulic Institute of Malaysia (NAHRIM)