ANALISIS CURAH HUJAN UNTUK PENDUGAAN DEBIT PUNCAK DENGAN METODE MELCHIOR PADA SUB- DAS BENGKULU HILIR SUNGAI AIR BENGKULU

This research aimed to determined how large the peak discharge which be occured in the
downstream of Sub DAS Bengkulu based on various continuously periods of the rain design by
using Rational Method of Melchior. Rainfall analysis by this method was an hydrology analysis
with statistical analysis. Estimation of optimum debit in this way used daily rainfall data for 32
years to be analyzed in stages starting from determining the average of maximum daily rainfall by
using partial method, then calculated the statistical parameters, selected the appropriate type of
frequency distribution, distribution and rain design test, and run off coefficient until the value of
time concentration was obtained. The results of this research showed that the distribution system
which compatible with the rainfall data was log normal distribution. While the data of land
arrangement and using, and characteristics of the Sub DAS obtained run off coefficient value (α)
of 0,38016, so by the results of research that the runoff coefficient value in the downstream of Sub
DAS Bengkulu was 138,5785 m3/second, with the time concentration of 19,126 hours on an area
of 224,026 km2 for 2 years period.