PENENTUAN KEHILANGAN AIR DARI HUJAN PADA SUB-DAS NGRANCAH HULU KABUPATEN KULONPROGO YOGYAKARTA MENGGUNAKAN METODE KOEFISIEN ALIRAN SESAAT
Abstract: Hydrologic response
of a watershed or sub-watershed to the presence of rain isan interesting study
in order to know the character of a watershed hydrology. Besides itcan be used
to predict soil and vegetation response to rainfall in a watershed, the
resultsof this study can also be used to calculate the potential of rain water
into surfacestreams. This will be very useful to see how big the potential
occurrence of floods froma river stream in case of rain. There are several
methods to test the hydrologic responseof a watershed or sub-watershed. One of
widely used model is the moment flowcoefficient (MFC). This study aims to
predict some parameters of hydrologicalresponse in the Ngrancah Hulu
sub-watershed in Yogyakarta Province using MFCmodel. The parameters examined,
i.e the flow coefficient for a moment, lose waterfrom the rain (watershed
response to rain), and the potential of rain water come intostreams. The study
begins by defining the characteristics of rainfall and flow ratesthrough the
primary and secondary data analysis, followed by the analyzes of waterlosses
using the MFC model, and analyzes the potential of rain water into streams.
Thestudy found that the moment flow coefficient in the study is the low level,
which meansthat in the sub-watershed, only a little rain water flows into the
rivers. The amount ofrain water lost is influenced by variables including heavy
rain, I-max, long rains and theAPI-7 days respectively. From the calculations,
it is obtained the equation for waterloss Y = 0.898 P + 0.03308. Flow
coefficient value is not in the normal classification,i.e with an average value
of 0.095. The amount of rain in the area of research becomingthe flow are
10.07% of the total of each rainfall event.
Penulis: Evi Nadhifah
Kode Jurnal: jpbiologidd100094
