Authors :
F.S Al-Hinai; L.N. Gunawardhana; I.S Al-Shaqsi
Volume/Issue :
Volume 7 - 2022, Issue 11 - November
Google Scholar :
https://bit.ly/3IIfn9N
DOI :
https://doi.org/10.5281/zenodo.7439896
Abstract :
The estimation of peak-flow corresponding to a
given return period is a significant factor in designing
hydraulic structures. There are many methods used to
estimate the peak-flow. In this study, two methods were
used to estimate the peak-flow. Firstly, an appropriate
probability distribution function is fitted to the recorded
annual maximum (AM) wadi-flow series to determine
wadi-flow rate with a certain exceedance probability.
Secondly, in the absence of long-term wadi-flow data,
peak-flows simulated by rainfall-runoff model are used. In
this study, these two methods were used to estimate the
differences between the design peak-flows in the Wadi AlKhoud catchment area. For the use of hydrological
modelling, Intensity-Duration- Frequency (IDF) curves
were developed by using General Extreme Value
Probability Distribution (GEV) function. KolmogorovSmirnov test was used for testing the goodness of GEV fit
with observed data. Comparison of IDF curves developed
for the Wadi Al-Khoud area and the once presented in
Highway Design Manual in Oman (2010) indicated that
the difference between the IDF curves becomes larger as
the return period increases. Geospatial Hydrologic
Modeling Extension (HEC-GeoHMS) and the rainfallrunoff model (HEC-HMS) were used for delineating the
catchment area and simulating rainfall-wadi flow relation.
The 10-year peak-flow estimated by the observed wadiflow records is 503.37 m3
/s, which is much different from
the average peak-flows of the simulated 10 scenarios
(2877.82 m3
/s). This difference can be attributed to the
absence of the long-term rainfall and wadi-flow data for
the probability estimations and the inability to capture the
spatial distribution of the rainfall over a large catchment
area as Wadi Al-Khoud catchment.
Keywords :
Annual Maximum Wadi-Flow, GEV Distribution, HEC-HMS, IDF Curves, Peak-Flow, Wadi Al-Khoud
The estimation of peak-flow corresponding to a
given return period is a significant factor in designing
hydraulic structures. There are many methods used to
estimate the peak-flow. In this study, two methods were
used to estimate the peak-flow. Firstly, an appropriate
probability distribution function is fitted to the recorded
annual maximum (AM) wadi-flow series to determine
wadi-flow rate with a certain exceedance probability.
Secondly, in the absence of long-term wadi-flow data,
peak-flows simulated by rainfall-runoff model are used. In
this study, these two methods were used to estimate the
differences between the design peak-flows in the Wadi AlKhoud catchment area. For the use of hydrological
modelling, Intensity-Duration- Frequency (IDF) curves
were developed by using General Extreme Value
Probability Distribution (GEV) function. KolmogorovSmirnov test was used for testing the goodness of GEV fit
with observed data. Comparison of IDF curves developed
for the Wadi Al-Khoud area and the once presented in
Highway Design Manual in Oman (2010) indicated that
the difference between the IDF curves becomes larger as
the return period increases. Geospatial Hydrologic
Modeling Extension (HEC-GeoHMS) and the rainfallrunoff model (HEC-HMS) were used for delineating the
catchment area and simulating rainfall-wadi flow relation.
The 10-year peak-flow estimated by the observed wadiflow records is 503.37 m3
/s, which is much different from
the average peak-flows of the simulated 10 scenarios
(2877.82 m3
/s). This difference can be attributed to the
absence of the long-term rainfall and wadi-flow data for
the probability estimations and the inability to capture the
spatial distribution of the rainfall over a large catchment
area as Wadi Al-Khoud catchment.
Keywords :
Annual Maximum Wadi-Flow, GEV Distribution, HEC-HMS, IDF Curves, Peak-Flow, Wadi Al-Khoud
