An Experiment Concerning Tsunami Prevention Techniques
The effectiveness of three different types of coastal barriers in deterring a simulated tsunami or hurricane wave will be determined. Three six-inch tall barrier designs will be tested in a bath-tub. A design of this type could significantly reduce tsunami and hurricane deaths like those recently witnessed in Hurricane Katrina. It could also prevent major property damage to low lying coastal areas such as New Orleans, and therefore is of great importance to society. The topic has been researched a great deal by the global scientific community and various humanitarian aid organizations. Most scientists currently agree that barrier reefs and coastal marshes are an invaluable resource for dissipating the energy of tsunami waves (Vince, 2005). Rapidly growing industry in tsunami affected areas and the deforestation associated with it are destroying these natural protectors (Flint, 2005) and creating a vacancy that must be filled by artificial barriers (Lerrder, 2005). Other economic research shows that the cost of these barriers would be over thirty times the annual income of the average Sri Lankan coastal villager (Uyana, 2005). In summary, the natural barriers that have protected tsunami and hurricane affected regions in the past are being destroyed, and the funds needed to rebuild them artificially are absent (Gibson, 2005).
Three designs will be tested: a flat, vertical wall (similar to the Galveston seawall built in 1908), a sloping revetment of styrofoam "rocks", and an overhang that allows water to flow underneath it. The three different barrier designs differ greatly in the ways they dissipate energy from incoming waves. The vertical wall design uses its sheer mass to stop the waves by using the principle of Newton's third law of motion: "for every action there is an equal and opposite reaction," meaning that the waves will be deflected from the wall with the same amount of force they crashed into it with (Newton, 1687). The second design, a revetment at a forty-five degree angle with numerous pieces of styrofoam strewn across it, allows the water to flow through its porous and maze-like surface, redirecting its motion so many times that it will no longer have any force behind it once it reaches the top. The third design, an overhang jutting out from the shoreline, allows the water to crash into the beach with an almost infinite amount of force while still not allowing any to spill over into the community. This third design will also contribute to massive erosion problems and eventually wash itself away, however.
The effectiveness of each design will be measured in the amplitude of the wave (in centimeters) once it has gone past the barrier onto the simulated shoreline. This will demonstrate the effectiveness of the barrier by showing how the height of the water surge is reduced. The amplitude of a wave is the length from its middle to its crest.
The design of a water barrier on a shoreline can greatly reduce the amplitude of incoming waves during natural disasters. If the energy of an incoming wave is dissipated by the barrier, the height of the wave, and consequentially the amplitude, will decrease greatly, preventing the wave from moving over the barrier. The greater the height of the barrier, the taller wave it will be able to deflect before water surges over it and damages property in a coastal community.
The effectiveness of three coastal barriers will be tested to show which design is most effective at reducing the amplitude of simulated waves. If the overhang design is used, then the amplitude of the wave will decrease. Since natural barriers are being destroyed by industry and tourism, artificial barriers such as these will be crucial to the survival of coastal communities.