Wind Flow Simulation and Testing for Mitigating Coastal Disaster under Hurricanes

Chowdhury Gan Arindam, Huang Peng and Bitsuamlak Girma

Hurricane-induced economic losses in coastal communities have increased steadily in the U.S. during the past 50 years. The current research at the International Hurricane Research Center at Florida International University (FIU) aims at addressing two high priority areas for hurricane research, namely, ‘Impacts and Interactions’ and ‘Preparedness and Building Resiliency.’ The research focuses on first-of-its-kind full-scale destructive testing on houses and other structures that can lead to better understanding of hurricane-structure interaction and the development of effective mitigation measures against hurricane disasters. The accuracy of the full-scale testing and its success in helping to mitigate hurricane damages will depend largely on the development of a full-scale testing facility capable of generating a wind field with mean and turbulence characteristics reasonably resembling those of real hurricane winds. This paper describes the new FIU full-scale testing facility; the initial wind field characteristics and a comparison with those of real hurricane winds; ongoing research and findings on the enhancement of the wind field simulation through the application of active and passive flow management devices; and the future research plan and vision for using this facility to help sustain the economy in hurricane-prone coastal regions. The research described in this paper is a significant component of efforts required to sustain the coastal economy in hurricane disaster prone coastal regions.

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Using Geoinformatics to characterise Areas Vulnerable to Debris Flows in the Tropics; A Case Study of Northern Trinidad, West Indies

Baban Serwan M. J. and Aliasgar Kelly

The long chain of Caribbean islands, including Trinidad and Tobago, surrounded by the Atlantic Ocean is annually subjected to hurricanes leading to extensive destruction by debris flows. In July 2005, the passage of hurricane Emily in close proximity to Trinidad resulted in debris flows in the Northern Range in Trinidad. This paper outlines a geo informatics based deductive approach to identify and map physical and environmental conditions making an area vulnerable to debris flows. Geo informatics was used to map and identify 50 debris flows occurred during Emily and to identify the physical conditions (soil, geology, elevation, land use/cover and slope) at the debris flows locations. The results showed that the highest frequency of debris flows occurrence and physical conditions susceptible to failure were in Sandy clay loam; Slate, Siltstone and Sandstone and Quartzite, Phyllite; Slope angle 0 – 30 degree, Forest land cover and at the elevation range of 100-200m. This combination accounted for 40% of the debris flows. This information can used in the planning process and to determine other vulnerable areas.

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Evaluation of 2004 December 26 Tsunami Wave Hazardness with Coastal Bathymetry and Geomorphology; A Case Study in Sri Lanka

Jinadasa S.U.P.

The Indian Ocean mega tsunami was the most devastated natural disaster that ever happened in Sri Lanka’s history. According to the available records, Sri Lanka lost more than 40,000 lives and more than 5000 are still missing. The loss of property has never been estimated. The aim of this post-tsunami survey was to acquire ground truth data on tsunami run-up and horizontal inundations and to correlate them with severerity, coastal bathymetry and geo-morphology. The correlation of ground truth data with coastal bathymetry and morphology provided a broader view of the behaviour of tsunami wave propagation. Coastal bathymetry and geomorphology are the major factors that determine the influence and severity of the tsunami waves. The study revealed that the average width of horizontal inundation is about 2 km and maximum upto 13 km. The measured wave observed run up versus horizontal inundation and predicted curve was plotted at the same scale. However, calculated and observed values show some differences from each other. For most of the cases, observed values exce­eded the estimated values, but in some cases app­eared below the expected height. Later, the coastal bat­hymetry was considered and it revealed that the tsun­ami waves scattered with narrow shelf, canyons and coastal bays to increase the tsunami wave heig­hts. Specially, Payagala (run-up 4.5 m and inu­ndat­ion 0.5 km) was severely affected due to the presence of a coastal canyon. Another vital factor that was found at Paraliya (run-up 10 m and inun­dation 1.5 km) to increase tsunami height was the impact of near shore canyon and coral mining pits in the area. The studies which were carried out on the Southern coast of Sri Lanka revealed that the coastal bays caused funnelling of the tsunami waves and the younger sand dunes at low lands between older dunes were breached by tsunami waves, causing severe damages. Also, it showed that the initial Tsunami wave arrived at the area at 08:50 am local time and the second wave arrived 20 minutes later; thus height of the second wave was further enhanced due to superimposition of the incoming wave with the refle­cted wave at the foreland, due to shallow and narrow continental shelf. The study clearly estab­lishes that the coastal morphology serves as a critical parameter in protecting the coastline from ocean-based disa­sters. However, protective morphological barri­ers were caused to increase severity of tsunami wav­es on low land area due to the compression of waves.

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Study of the Distribution of 137Cs in the Pine in Northern Ukraine after the Chernobyl Nuclear Accident

Ben-Bolie G. H., Owono A. P., Ekobena F. H. P. and Abega C. R.

The purpose of this study is to evaluate the distribution of 137Cs in pine trees located in several sites of northern Ukraine, following the Chernobyl nuclear catastrophe and to determine the relation between this distribution and the rate of contamin­ation of the region. The analysis of measurements performed in northern Ukraine in 1995 show the influence of the physiological parameters of pine in the radiocaesium distribution, as well as the existence of some parts of the pine that can be considered as 137Cs storage areas so called reservoirs.

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Climate Change, Disasters and India Issues, Concerns and Opportunities

Chauhan Sunil

The paper examines the climate change scenario in context of India, the future projections of the Intergovernmental Panel on Climate Change (IPCC) and other regional assessments, along with the disaster profile of the country and the trend of rising disasters. For India, tackling the challenge of climate change and increase in disaster risks posits particular significance, presently poised as she is in an upward development trajectory. Valuable time and resources would be consumed in handling the increasing risks, which would impinge on its development, unless appropriate mitigation measures and mechanisms are not put in place now, and policies redefined to address the challenge. An analysis of the impact of climate change on the risk of natural hazards in India is put forth with proposed preparedness strategies and emergent policy imperatives. A range of options and strategies to deal with disaster risk reduction and climate risk reduction are viewed from a ‘risk management’ approach. Ensuring that development planning processes integrate climate risks as well as disaster risks will require ‘risk identification’, i.e. bringing together and effectively disseminating information on vulnerability and hazards. It will also require a range of risk reduction and risk spreading options.

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Geoelectrical Investigation of Erosion and Flooding using the Lithologic Compositions of Erosion and Flood- Stricken Road in Ukanafun Local Government Area, Akwa Ibom State, Southern Nigeria

George N. J. , Akpan A. E. , Obot I.B. and Akpanetuk N.J.

Vertical electrical sounding was used to delineate the lithology of erosion and flood- stricken road in Ukanafun Local Government Area of Akwa Ibom State, Southern Nigeria. The area under study lies between latitude 40 551N and latitude 50 001N and longitude 70 301 E and longitude 70 401 E. The infor­mation realized from the resistivity data and the logg­ed boreholes show that the depths penetrated by geo­electric current have sandy formations intercalated with clay minerals and with specific lateral distribu­tion and thicknesses. The erosion and flooding in the study were considered in terms of the porosity and permeability of rock units realized in the area which were compared to the theoretical specific yield and specific retention of similar rock matrix. The permea­bility of sandy bed units provokes soil-flow, soil creep and landslide while the presence of clay causes flooding by adhering the soil water to its surface.

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Characteristics of Rainwater in Nellore District of Andhra Pradesh, India

Sunitha Thota , Hariprasad P., Keerthi K., Valli Manikam and Muralikrishna I.V.

The chemical characteristics of the rainwater samples collected during the monsoon season of 2006 and 2007 have been analyzed for Nellore district. The impact of precipitation quantity and chemical nature was studied. The paper describes the ionic constitutes in the rainwater and the relation between seawater and rainwater. Constituent seawater fractions for coastal mandals were calculated and compared with that of all mandals in the district. Clustering of the sample in the range of pH 6.1 to 7.1 was observed. Correlation between calcium, sodium and magnesium with chlorides was significant. Extreme variations in calcium concentration were observed due to weather modification techniques used on some occasions.

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