KAJIAN DEBIT BANJIR AKIBAT PERUBAHAN PENGGUNAAN LAHAN DI SUB DAS BELIK, DAERAH ISTIMEWA YOGYAKARTA
Belik sub-watershed is a catchment area that located in urban area of Yogyakarta regency and Sleman regency. Flood is often occur in that area when the rainy season because of development of impermeable land, so that increasing the runoff coefficient. Because of that, this research have purpose to s...
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| Main Authors: | , |
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| Format: | Theses and Dissertations NonPeerReviewed |
| Published: |
[Yogyakarta] : Universitas Gadjah Mada
2014
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| Subjects: | |
| Online Access: | https://repository.ugm.ac.id/132771/ http://etd.ugm.ac.id/index.php?mod=penelitian_detail&sub=PenelitianDetail&act=view&typ=html&buku_id=73314 |
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| Summary: | Belik sub-watershed is a catchment area that located in urban area of
Yogyakarta regency and Sleman regency. Flood is often occur in that area when
the rainy season because of development of impermeable land, so that increasing
the runoff coefficient. Because of that, this research have purpose to study land
use change spatially and temporally on the year of 2003 and 2012, to calculate
flood discharge in study area with various return period connected with river
capacity, and to analyze influence of land use change to flood discharge in study
area.
Interpretation method of satellite imagery is used to know land use on
2003 whereas field check according to interpretation result is used to know land
use on 2012. Land use change can be known using overlay method both of the
map on that year. Frequency analysis with return period of 2, 5, 10, and 20 years
and Mononobe formula are used to calculate rain intensity whereas flood
discharge is calculated using rational method. River capacity is calculated using
slope-area method to know that flood discharge can be accommodated or not.
The result of this research show that the most decreasing land use areal is
area with vegetation which is 23,47 Ha (3,44 %) whereas the most increasing
land use areal is real estate areas which is 22,86 Ha (3,34 %). Flood discharge
increase from year 2003 to year 2012 in all of catchment area. River capacity of
Karangwuni, Klebengan, Lembah, and Klitren catchment area cannot
accommodate that discharge whereas river capacity of main catchment area is
36,07 m3/s can accommodate discharge with return period of 2 years. The
increasing of runoff coefficient average in study area is 5,17 % - 16,28 % because
of land use change to impermeable land so that increase flood discharge. Flood
discharge that cannot be accommodated by the river causes flood and puddle in
study area during rainy season. |
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