Tsunami mitigation by coastal vegetation considering the effect of tree breaking

After the Indian Ocean Tsunami in 2004, several studies quantitatively investigated the effects of coastal vegetation on tsunami mitigation, but the effects of a limited forest with a small aspect ratio on tsunami mitigation were not yet elucidated. Therefore, the objective of this study was to estimate numerically the effect of the width-length ratio (aspect ratio) of a coastal forest on tsunami mitigation. Numerical simulations were performed using two-dimensional nonlinear long-wave equations that included bed resistance, drag, and turbulence-induced shear forces due to interaction with the forest. When a limited dense forest exists, the tsunami at the edge of the forest diffracts and collides behind the forest, and the fluid force becomes larger than the case without a forest. In particular, when the aspect ratio is from 1 to 4, the effect of a collision behind the forest becomes very great. However, if the aspect ratio is 4 or larger, the effect of a collision becomes smaller.

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A proposal for tsunami mitigation by using coastal vegetations

Journal of Natural Resources and Development ◽

10.5027/jnrd.v3i0.07 ◽

2013 ◽

Vol 3 ◽

pp. 85-95

Author(s):

Djati Mardiatno

Keyword(s):

Avicennia Marina ◽

Research Area ◽

Anacardium Occidentale ◽

Coastal Vegetation ◽

Survey Method ◽

Main Trunk ◽

Coastal Morphology ◽

Trunk Diameter ◽

Density Correlation ◽

Tsunami Mitigation

This research was conducted at the southern coastal area of central Java Island, Indonesia. It is aimed to identify several coastal vegetation characteristics for development of guideline for planning and design of tsunami mitigation. Survey method was applied to observe common coastal vegetation in the research area. Data collected from the survey consisted of vegetation parameters and coastal morphology. All selected vegetations were analyzed for their allometry relation of each species, maximum density, correlation between breaking moment and trunk diameter of each tree species, and correlation between trunk diameter and spacing between trees for each species. For coastal morphology, it was focused on topography and elevation from sea level. The results show that trees with the hard wood will be stronger to hold the pull moment on the main trunk. Younger trees with smaller diameter tend to be more flexible, thus they will unbreakable during the test. The other trees which have flexible trunk such as Terminalia catappa and Anacardium occidentale were often pulled out their roots than broken on their trunks. To obtain more extensive characteristic, it is necessary to carry out advanced measurements, especially on the older trees which have more than 10 cm diameter. Coastal areas consist of mud and sand materials tend to have a high tsunami risk, although mitigation treatments were different for both types. At the muddy area, the recommended vegetation are Avicennia marina and Rhizophora mucronata, meanwhile Casuarina equisetifolia and Anacardium occidentale, due to their high flexibility, will be more suitable on the sandy coast. Both types should be planted parallel to the shoreline. Casuarina is planted in the frontline followed by Anacardium behind it.

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Flume Experiments on Flow Analysis and Energy Reduction through a Compound Tsunami Mitigation System with a Seaward Embankment and Landward Vegetation over a Mound

Geosciences ◽

10.3390/geosciences11020090 ◽

2021 ◽

Vol 11 (2) ◽

pp. 90

Author(s):

Md Abedur Rahman ◽

Norio Tanaka ◽

A. H. M. Rashedunnabi

Keyword(s):

Laboratory Experiments ◽

Flow Analysis ◽

Maximum Energy ◽

Energy Reduction ◽

Coastal Vegetation ◽

Vegetation Density ◽

Flow Conditions ◽

Flume Experiments ◽

Tsunami Inundation ◽

Tsunami Mitigation

As a countermeasure against tsunami inundation, the present study conducted a series of laboratory experiments using a compound mitigation system in which a seaward embankment (E) followed by landward coastal vegetation (V) over a mound (M) (EMV) was investigated in supercritical flow conditions. The changes of flow around the mitigation system and energy reduction were clarified under varying conditions of mound height and vegetation density. Cases of an embankment followed by only a mound (EMNV) were also considered for comparison. Experimental results showed that three basic types of flow structures were observed within the mitigation system in EMV cases. A water cushion was created within the mitigation system mainly due to the combined effects of the mound and vegetation. It significantly reduced the maximum total energy in EMV cases by approximately 41–66%, whereas in EMNV cases, the maximum energy reduction was found to be 23–65%. Increments in both mound height and vegetation density increased the intensity of the water cushion within the mitigation system by offering more drag and reflecting the flow, and hence, significantly reduced the energy of the flow.

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Analysis and Evaluation of Tsunami Mitigation Effects by Coastal Vegetation

Journal of Japan Society of Civil Engineers Ser B2 (Coastal Engineering) ◽

10.2208/kaigan.65.366 ◽

2009 ◽

Vol 65 (1) ◽

pp. 366-370

Author(s):

Kosuke IIMURA ◽

Norio TANAKA ◽

Katsutoshi TANIMOTO ◽

Shigenobu TANAKA

Keyword(s):

Coastal Vegetation ◽

Analysis And Evaluation ◽

Tsunami Mitigation

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TSUNAMI ACEH 2004 SEBAGAI DASAR PENATAAN RUANG KOTA MEULABOH

Jurnal Sains dan Teknologi Indonesia ◽

10.29122/jsti.v13i2.887 ◽

2013 ◽

Vol 13 (2) ◽

Author(s):

Wisyanto Wisyanto

Keyword(s):

Coastal Area ◽

Building Damage ◽

Tsunami Hazard ◽

The Road ◽

Tsunami Disaster ◽

Landuse Planning ◽

The Future ◽

Tsunami Mitigation ◽

Potential Losses ◽

The Impact

Tsunami which was generated by the 2004 Aceh eartquake has beenhaunting our life. The building damage due to the tsunami could be seenthroughout Meulaboh Coastal Area. Appearing of the physical loss wasclose to our fault. It was caused by the use dan plan of the land withoutconsidering a tsunami disaster threat. Learning from that event, we haveconducted a research on the pattern of damage that caused by the 2004tsunami. Based on the analysis of tsunami hazard intensity and thepattern of building damage, it has been made a landuse planning whichbased on tsunami mitigation for Meulaboh. Tsunami mitigation-based ofMeulaboh landuse planning was made by intergrating some aspects, suchas tsunami protection using pandanus greenbelt, embankment along withhigh plants and also arranging the direction of roads and setting of building forming a rhombus-shaped. The rhombus-shaped of setting of the road and building would reduce the impact of tsunamic wave. It is expected that these all comprehensive landuse planning will minimize potential losses in the future .

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U.S. Army Coastal Engineering Research Center's Ecology Program

Water Science & Technology ◽

10.2166/wst.1984.0085 ◽

1984 ◽

Vol 16 (3-4) ◽

pp. 525-532

Author(s):

E J Pullen ◽

P L Knutson ◽

A K Hurme

Keyword(s):

Coastal Engineering ◽

Coastal Vegetation ◽

Army Corps ◽

Army Corps Of Engineers ◽

Engineering Research ◽

Navigation Channel ◽

Biological Environment ◽

Ecology Program ◽

The U.S ◽

Shore Erosion

The Coastal Engineering Research Center at Fort Belvoir, Virginia, is responsible for research that supports the U.S. Army Corps of Engineers' Civil Works program. This research involves coastal navigation, channel design and maintenance, storm flooding, shore erosion control, and coastal ecology. The ecology research is focused on two major areas: (1) use of coastal vegetation for engineering purposes and (2) effects of coastal engineering activities on the biological environment. The objectives and accomplishments of the ecology research are discussed and specific examples of field guidance are presented.

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Probabilistic Tsunami Hazard Analysis of Inundated Buildings Following a Subaqueous Volcanic Explosion Based on the 1716 Tsunami Scenario in Taal Lake, Philippines

Geosciences ◽

10.3390/geosciences11020092 ◽

2021 ◽

Vol 11 (2) ◽

pp. 92

Author(s):

Kwanchai Pakoksung ◽

Anawat Suppasri ◽

Fumihiko Imamura

Keyword(s):

Hazard Analysis ◽

Active Volcano ◽

The Philippines ◽

Tsunami Hazard ◽

Initial Water ◽

Volcanic Explosion ◽

Inundation Depth ◽

Tsunami Mitigation ◽

Probabilistic Tsunami Hazard Analysis ◽

Tunami N2

A probabilistic hazard analysis of a tsunami generated by a subaqueous volcanic explosion was performed for Taal Lake in the Philippines. The Taal volcano at Taal Lake is an active volcano on Luzon Island in the Philippines, and its eruption would potentially generate tsunamis in the lake. This study aimed to analyze a probabilistic tsunami hazard of inundated buildings for tsunami mitigation in future scenarios. To determine the probabilistic tsunami hazard, different explosion diameters were used to generate tsunamis of different magnitudes in the TUNAMI-N2 model. The initial water level in the tsunami model was estimated based on the explosion energy. The tsunami-induced inundation from the TUNAMI-N2 model was overlaid on the distribution of buildings. The tsunami hazard analysis of inundated buildings was performed by using the maximum inundation depth in each explosion case. These products were used to calculate the probability of the inundated building given the occurrence of a subaqueous explosion. The results from this study can be used for future tsunami mitigation if a tsunami is generated by a subaqueous volcanic explosion.

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The effect on coastal vegetation of trampling on a parabolic dune

Aeolian Research ◽

10.1016/j.aeolia.2010.03.001 ◽

2010 ◽

Vol 2 (2-3) ◽

pp. 105-111 ◽

Cited By ~ 21

Author(s):

Patrick Hesp ◽

Phillip Schmutz ◽

M.L. (Marisa) Martinez ◽

Luke Driskell ◽

Ryan Orgera ◽

...

Keyword(s):

Coastal Vegetation

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Numerical Investigation of Wave Period Influence on Long Wave Run-Up on Slope With Rigid Vegetation

Volume 7: Ocean Engineering ◽

10.1115/omae2016-54298 ◽

2016 ◽

Author(s):

Jun Tang ◽

Yongming Shen

Keyword(s):

Shallow Water Equations ◽

Water Wave ◽

Wave Period ◽

Coastal Vegetation ◽

Coastal Structures ◽

Rigid Vegetation ◽

Comparison With Experiment ◽

Long Wave ◽

Nonlinear Shallow Water Equations ◽

Run Up

Coastal vegetation can not only provide shade to coastal structures but also reduce wave run-up. Study of long water wave climb on vegetation beach is fundamental to understanding that how wave run-up may be reduced by planted vegetation along coastline. The present study investigates wave period influence on long wave run-up on a partially-vegetated plane slope via numerical simulation. The numerical model is based on an implementation of Morison’s formulation for rigid structures induced inertia and drag stresses in the nonlinear shallow water equations. The numerical scheme is validated by comparison with experiment results. The model is then applied to investigate long wave with diverse periods propagating and run-up on a partially-vegetated 1:20 plane slope, and the sensitivity of run-up to wave period is investigated based on the numerical results.

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