ANALISIS INTENSITAS CURAH HUJAN EFEKTIF DAN WORKING RAINFALL UNTUK DASAR PENGEMBANGAN KRITERIA PERINGATAN KEJADIAN ALIRAN LAHAR (Studi Kasus Kali Gendol, Kawasan Gunung Merapi)
After the eruption of Mount Merapi in October-November 2010, at least 140 million m 3 volcanic material piled on the back of Merapi and some flows shortly on and after the eruption through the rivers that disgorge on peak of Merapi. To date, the impact from the silting of the river and falling volca...
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| Main Authors: | , |
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| Format: | Theses and Dissertations NonPeerReviewed |
| Published: |
[Yogyakarta] : Universitas Gadjah Mada
2013
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| Online Access: | https://repository.ugm.ac.id/118713/ http://etd.ugm.ac.id/index.php?mod=penelitian_detail&sub=PenelitianDetail&act=view&typ=html&buku_id=58687 |
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| Institution: | Universitas Gadjah Mada |
| Summary: | After the eruption of Mount Merapi in October-November 2010, at least 140
million m
3
volcanic material piled on the back of Merapi and some flows shortly on
and after the eruption through the rivers that disgorge on peak of Merapi. To date, the
impact from the silting of the river and falling volcanic material from the top of
Merapi cause lahar flood which swept through areas far enough from the peak of
Merapi. Given the dangers and impact caused by the lahar flow, as well as the
limitations of existing data, the simplest method by perform rainfall data analysis is
expected to predict lahar flow events in Gendol river.
The analysis method performed by setting of standard rainfall for warning and
evacuation were used for prediction of sediment disasters based on Guidelines for
Development of Warning and Evacuation System Against sediment Disasters in
Developing Countries, published by the Ministry of Land, Infrastructure and
Transport, Infrastructure Development Institute - Japan, namely: (1) specifies serial
rain which total amount of rain � 80 mm, (2) Calculations on working rainfall (RW)
and working antecedent rainfall (RWA), (3) Calculation on effective rainfall (RE),
effective time, and effective rainfall intensity (IE), (4) Make a graph of effective
rainfall intensity and working rainfall, (5) Predict the potential for debris flow by
calculating the probability of debris flow occurrence on Gendol river.
The reseach results showed that the number of reviewed serial rain with total
value � 80 mm is 9.28% of the whole serial rain, and 12.5% of them caused lahar
flow in Gendol River. Debris flow occurrence probability on total rainfall amount of
� 80 mm that may occur on Gendol river amounted to 1.89%. This value represents
less possibility of debris flow in Gendol River, this is due to the rain conditions in the
Gendol Watershed different from the situation in Japan as well as the limitations of
the available data. It is recommended for further research on the limitation of total
rainfall in accordance with the conditions in Gendol Watershed by considering other
parameters becoming the lahar flow controller factor. Further, necessary to perform
the analysis using rain catchment method by averaging rainfall values on each of
serial rain. |
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