1 / 16

Evaluation of the effect of the disaster prevention technique using coastal farmlands

Evaluation of the effect of the disaster prevention technique using coastal farmlands . Kiri H. and H. Tanji National Institute for Rural Engineering National Agriculture and Food Research Organization (NARO). The Great East Japan Earthquake Tsunami. Local time : 14:46 March 11, 2011

shaw
Download Presentation

Evaluation of the effect of the disaster prevention technique using coastal farmlands

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Evaluation of the effect of the disaster prevention technique using coastal farmlands Kiri H. and H. Tanji National Institute for Rural Engineering National Agriculture and Food Research Organization (NARO)

  2. The Great East Japan Earthquake Tsunami • Local time : 14:46 March 11, 2011 • Magnitude : 9.0 • The rupture area : 450 km x 200km • Stricken coast : 1,300 km • Inundated area : over 400km2 Run-up Inundation Joint survey group Joint survey group

  3. Seawall and CoastalDikes

  4. Drainage facilities and farmlands

  5. The tsunami disaster in this scale is not a just once experience. Itrepeat in 600 to 1,000 years. To prevent huge tsunami disasters What should we do? The Central Disaster Management Council Committee for Technical Investigation on Countermeasures for Earthquakes and Tsunamis Based on the Lessons Learned from the Earthquake

  6. Basic principles for Tsunami countermeasures For the future tsunami countermeasures … require the assumption of two levels of tsunamis. Tsunamis Possible Largest ( Level 2 ) Frequent ( Level 1 ) Return period 100~150 yr Not include the tsunami in 2011 Construct coastal protection facilities and breakwaters • Return period >1,000 yr • Comprehensive disaster management measures • Focus on the evacuation of local residents

  7. The Disaster-prevention farmland High durability banking Coastal Dike Drainage channel Wave breaker Farmlands Farmlands 3rd dike 2nd dike Salt control forest Energy dissipater Concept • Moving settlements near the coast to hilltops. • Readjusting large farms in the lowland area along the coast. • Permitting flooding of farmland in the case of a tsunami or a storm surge exceeding the planned height. • Having the function of a second dike assigned to inland roads and protecting property and human lives in evacuation space.

  8. Evaluation by a Hydraulic Model Test

  9. Hydraulic Models Normal farmland Disaster-prevention farmland

  10. Offshore wave

  11. Nearshore wave

  12. Tsunami run-up velocity~Normal farmlands~ Average 10.5 m/s Front speed Coast< Inland

  13. Tsunami run-up velocity~Disaster-prevention farmland~ Normal farmland Average 10.5 m/s Energy dissipated ! Average 5.9 m/s

  14. Inundation depth~Short wavelength~

  15. Inundation depth~Long wavelength~

  16. Conclusions • The effect of coastal farmland for flood prevention technique was evaluated by hydraulic model test. • The disaster prevention technique using coastal farmlands dissipates the energy of tsunami run-up. • The result of the hydraulic model test indicated that coastal farmlands decrease tsunami run-up for two minutes. • The effect of the disaster-prevention farmland at a model coast is also confirmed by a numerical simulation.

More Related