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Titel |
Reduction of tsunami inundation by coastal forests in Yogyakarta, Indonesia: a numerical study |
VerfasserIn |
W. Ohira, K. Honda, K. Harada |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1561-8633
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Digitales Dokument |
URL |
Erschienen |
In: Natural Hazards and Earth System Science ; 12, no. 1 ; Nr. 12, no. 1 (2012-01-11), S.85-95 |
Datensatznummer |
250010407
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Publikation (Nr.) |
copernicus.org/nhess-12-85-2012.pdf |
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Zusammenfassung |
Coastal forests are known to protect coastal areas from environmental
degradation. In this paper, we examined another important role of coastal
forests – to mitigate tsunami devastations to coastal areas. Using a
two-dimensional numerical model (Harada and Imamura model, 2005), we
evaluated the damping effects of a coastal forest to resist tsunami
inundation in Yogyakarta, Indonesia. In the simulations, we set up a two-km
long control forest with a representative topography of the study site and
experimented its damping performance sensitivity under various width
configurations, e.g. 20, 40, 60, 80, 100 and 200 m. The initial tsunami
wave was set such that the inundation depth at the front edge of the forest
would not exceed 4 m (tree fragility limit). The forest variables such as
species, density, DBH, height and canopy size were determined from a typical
forest of the site (Casuarina plantation, 4 trees/100 m2, Diameter at Breast
Height = 0.20 m). The results showed that coastal forest with 100 m width
reduced inundation flux, depth and area by 17.6, 7.0 and 5.7%,
respectively. Exponential models were found to describe the relationships
between forest width and tsunami inundation transmission. An additional
experiment was performed using actual topography and a forest plantation
plan with 100 m width for 2.46 km2. In this experiment, the results
showed that the plan would reduce inundation flux by 10.1%, while the
exponential model estimated it to be 10.6%, close to the numerical model
results. It suggests that statistical models of forest width and damping
effects are useful tools for plantation planning, as it allows for quicker
evaluation of the impact of coastal forest without simulation modeling that
requires a lot of data, time and computing power. |
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