BUILDING CAPACITY TO INSURE AGAINST DISASTER IN TUVALU
Consultants Report
SOPAC Technical Report 380
June 2005
This Study was funded by the Government of Taiwan/ROC
DISCLAIMER
The mention of products, technologies, companies does not imply recommendation or endorsement by SOPAC, neither does it imply that these are necessarily the best available for the purpose.
SOPAC Cataloguing-in-publication Data:
Shorten, Graham Building capacity to insure against disaster in Tuvalu/Graham Shorten, Susanne Schmall, & Stephen Oliver. – Suva: SOPAC, 2005.
140 p.: ill.; 30 cm ISSN: 1605-4377
1. Hazard assessment – Pacific Islands 2. Disaster management – Tuvalu I. Schmall, Susanne II. Oliver, Stephen III. SOPAC Technical Report 380 IV. Title
Table of Contents
EXECUTIVE SUMMARY...... 4
PART 1 – FIRST MISSION, MARCH 2004
1. Introduction and Approach ...... 7
2. Preliminary Assessment of Disaster Risk and Vulnerability in Nikulaelae 2.1 Reasons for choosing Nukulaelae as project area ...... 10 2.2 Population and Institutions in Nukulaelae ...... 11 2.3 Felt Disaster vulnerability and preparedness ...... 12
3. Disaster Related Problems and Potential Solutions in Nukulaelae 3.1 Housing ...... 14 3.2 Agriculture and Fisheries ...... 14 3.3 Coastal Erosion ...... 16 3.4 Water Supply ...... 17 3.5 Sanitation ...... 19 3.6 Solid Waste ...... 20
4. Preparation of Workshops in June 2004 4.1 Proposed Time Schedule for June/July 2004 ...... 21 4.2 Workshop Facilitation Team ...... 23 4.3 Participants for the Workshop ...... 26 4.4 Budget for Community Workshop and Multi-Stakeholder Workshop ...... 27 4.5 Potential mitigation options to emphasize on at the Workshop ...... 27 4.6 Next Project Steps for the Workshop Preparation ...... 28
Appendices 1: Resource Persons and Organizations Contacted ...... 29 2: Documents Reviewed ...... 30
PART 2 – SECOND MISSION, JUNE 2004
1. Objectives and Workplan ...... 31
2. Conclusions 2.1 Workshop in Funafuti ...... 35 2.2 Co-operation with the other disaster reduction programs ...... 35 2.3 Promotion of Project Proposals ...... 36
PART 3 – ANNEXES
Annex 1: Workshop Report: "Disaster Vulnerability and Mitigation Workshop, Funafuti”...... 38 Annex 2: Presentation on Cyclone Hazard to the Disaster Vulnerability and Mitigation Workshop...... 57 Annex 3: Proposals for Risk Treatment Projects (RESTRICTED, no circulation outside the SOPAC Secretariat) ...... 64 Annex 4: Photo Documentation to Complement the Project Proposals for Tuvalu...... 65 Annex 5: Presentation prepared for the National Summit on SustainableDevelopment (NSSD) in Funafuti in July, 2004, to be given by the National Disaster Coordinator (RESTRICTED, no circulation outside the SOPAC Secretariat)...... 70 Annex 6: Tuvalu Wave Risk Study – Global Environmental Modelling Systems (GEMS) Report 29/04, June 2005...... 71
Executive summary
This Technical Report titled “Building Capacity to Insure against Disaster in Tuvalu” describes the method and outcomes of the Taiwan/ROC funded project and its two missions.
During the first mission in March 2004, institutional appraisals and workshop preparations were carried out. The project combines hazard assessment for a pilot area as well as vulnerability assessment and community disaster mitigation planning in a selected community in Tuvalu. It is of vital importance for this project and the outcomes to integrate into the existing activities in the field of disaster assessment; preparedness and relief planned and carried out by the Tuvalu government, by Non- Government Organisations and regional development programs. The project seeks cooperation with other programmes in order to combine strengths and to optimise the allocation of funds. Hence the project will coordinate closely with existing SOPAC, FSPI and disaster-related programs and initiate a community participatory process to ascertain the needs of communities in relation to preparation and response to disasters.
The main objective of the second mission, in June 2004, was to carry out a community and multi-stakeholder workshop on disaster vulnerability and mitigation for the communities on the island of Fongafale in Funafuti atoll, Tuvalu.
A detailed workshop report is attached as Annex 1, and a presentation to that workshop as Annex 2. Following the analysis of the results of the workshop, a summary of mitigation issues was developed and is detailed in Annex 3*. Annex 4 forms a photo-documentation to the mitigation issues. Annex 5* is a copy of the presentation made to the Tuvalu National Summit on Sustainable Development during the period of the second mission; and Annex 6 is the recently received (June 2005) Tuvalu Wave Risk Study carried out by the Global Environmental Modelling Systems (GEMS).
* Annexes 3 and 5 are RESTRICTED, and not for circulation outside the SOPAC Secretariat.
PART 1 – FIRST MISSION, MARCH 2004
Taiwan-ROC funded project
Building Capacity to Insure against Disasters in Pacific Island Countries (Tuvalu)
South Pacific Applied Geoscience Commission (SOPAC)
Project Duration: February-July, 2004
Report on First Mission
7-16th March, 2004
“Institutional Appraisal and
Preparation of Workshops”
Dr Susanne Schmall
Geo-Ecologist, Community Adviser
Ebergoetzen, March 2004
6 1. Introduction and Approach
The first mission of the ROC-funded project “Building Capacity to Insure against Disasters in the Pacific Islands (Tuvalu)” by the South Pacific Applied Geoscience Commission (SOPAC) (hereafter in this text referred to as “the project”) was carried out in March 2004. The team was made up of consultants Dr Graham Shorten and Dr Susanne Schmall contracted by SOPAC and accompanied by Mr Noud Leenders from the SOPAC Community Risk Programme.
The project combines hazard assessment for a pilot area as well as vulnerability assessment and community disaster mitigation planning in a selected community in Tuvalu. It is of vital importance for this project to integrate into the existing activities in the field of disaster assessment; preparedness and relief planned and carried out by the Tuvalu government, by Non-Government Organisations and regional development programs. The project seeks cooperation with other programmes in order to combine strengths and to optimise the allocation of funds. Hence the project will coordinate closely with existing SOPAC, FSPi and disaster-related programs and initiate a community participatory process to ascertain the needs of communities in relation to preparation and response to disasters.
During this mission from 8-15th March, 2004 in Funafuti, an institutional appraisal was carried out (Appendix 1) in order to obtain a preliminary assessment of risk and disaster vulnerability, and preparedness as well as potential mitigation solutions for a pilot community (Chapter 2 and 3). The team is very grateful of having been accompanied and supported greatly by the Disaster Coordinator Sumeo Silu, National Disaster Management Unit, who organized all meetings during the week
The objective of this week was to prepare (1) a community vulnerability and mitigation planning workshop to develop mitigation projects aimed at providing risk-treatment solutions to the problems identified as well as (2) a multi-stakeholder workshop in Funafuti to discuss implementation and any refinements directly with the potential mitigation project participants (see Chapter 4).
7
8 /04 Mon 10.45 am Arrival Graham Shorten, Susanne Schmall, Noud Leenders (SOPAC) 2.00 pm Sumeo Silu (Disaster Coordinator, National Disaster Management Unit) 3.00 pm Annie Homasi (TANGO Coordinator) and Lilian Falealuga (Director of Tuvalu Red Cross Society) 9 Tues 9.30 am Lutelu Faavae (Permanent Secretary, Ministry of Natural Resources and Lands, National Representative of Tuvalu to SOPAC), Hon. Samuelu Penitala Teo (Minister of Natural Resources and Lands) 10.30 am Panapasi Nelesone (Secretary to Government) 11.30 am Kulene Sokotia (Acting Director of Lands and Survey Dept.) 3.00 pm Esi, Liliane, Malia, Tusiata, Lola (women from Nukulaelae with Head of Nukulaelae women organization), Petueli Noa (Youth Officer at Kaupule Nukulaelae) 6.00 pm Visit of Waste Dump Site 10 Wed 9.00 am Lilian Falealuga (Director of Tuvalu Red Cross Society) 10.00 am Hilia Vavae (Director of Meteorological Office) 11.00 am Hellani Tumua (Administrative Officer, AusAID Office), Pasemeta Sateko Talaapa (EU-NZAID In-Country Coordinator) 12.30 am Fanoanoaga Patolo (former Director of Lands and Survey) 3.00 pm Michael P.Y. Hsu (Chargé d´Affaires, Embassy of the Republic of China) 4.00 pm Hilia Vavae (Director of Meteorological Office) 11 Thu 10.00 am Sautia Malua (Director of Fisheries) 11.00 am Elu (Officer at Dept. of Agriculture) 2.00 pm Enate Evi (Officer at Dept. of Environment) 3.00 pm Kelesoma Salea (IWP Coordinator) 4.00 pm Annie Homasi (Director of TANGO) 12 Fri 9.00 am Annie Homasie (TANGO), Sumeo Silu (Disaster Coordinator, National Disaster Management Unit), Lilian Falealuga (Director of Tuvalu Red Cross Society) 10.00 am Filipo Taulima (Director of Works, Energy and Communications) 1.30 pm Fakavae Taomia (Secretary of Home Affairs) 2.30 pm Rt. Hon. Bikeni Paeniu (Minister for Finance, Economic and Industries) 3.00 pm Poni Faavae (Coordinator Napa) 13 Sat Visit of Conservation Area, Beach Profiles 14 Sun Beach Profiles, Draft Short Report 15 Mon 8.30 am Sumeo Silu (Disaster Coordinator, National Disaster Management Unit) 11.30 am Departure 16 Tues 9.00 am Russell Howorth (Deputy Director), Alan Mearns (Manager Community Risk Program, SOPAC), Stephen Booth (Coordinator of EU-Program Reducing Vulnerability of Pacific ACP States, SOPAC), Robert Smith (Senior Adviser Marine Geophysics, SOPAC), Franck Martin (ICT Specialist, SOPAC)
Figure 1: In-Country Work Program in March 2004
8 In order to run a successful community workshop on disaster vulnerability and mitigation planning, as much information as possible needs to be collected beforehand. During the limited time of one week in Funafuti, the following sources for a preliminary assessment of disaster vulnerability and disaster mitigation options in Nukulaelae had been consulted:
• Five women from Nukulaelae, who attended the National Women’s Day in Funafuti, with the head of the women organization on Nukuluaelae (Photo 1) • The Youth Officer of the Kaupule in Nukulaelae • Rt. Hon. Bikeni Paeniu, Minister for Finance, Economic and Industries • The other representatives of the organisations visited during the week • The Population Census 2002 • Reynolds, C., Eng., B., Eng., C., MICE, MIWEM: Tuvalu Water and Sanitation Plan for Period 1993-2002 and other documents (Appendix 2) • The SOPAC web page http://www.sopac.org.fj
An assessment of physical data for storm surge, storm wave and storm wind modelling was carried out and forwarded to and incorporated in a cyclone storm wave modelling to be done by Stephen Oliver of GEMS Pty Ltd. This included the profiling and assessment of the storm berms on the ocean side of Fongafale by Graham Shorten and Noud Leenders.
9 2. Preliminary assessment of disaster risk and vulnerability in Nukulaelae
2.1 Reasons for choosing Nukulaelae as project area
Nukulaelae was chosen as the area of application for the community component of the project based on the following reasons for selection:
• Nukulaelae lies in the southern area of the Tuvalu group which, in the long term, is most likely to experience the greatest hazard from cyclone due to the fact that cyclones generally form in the central/northern region and move southward, more often than not intensifying as they do so. The population on the southernmost island, Niulakita – arguably with the highest level of cyclone hazard - is too small for a suitable pilot community (35 people, with 83 inhabitants/sq. km. being the lowest population density of the Tuvalu islands1) • Opportunity to collaborate directly on a disaster-related project with a Non- Government Organisation (FSPI /TANGO) on the AusAID-funded Pacific Disaster Preparedness Strengthening Program which has chosen Tuvalu and Fiji Islands as pilot areas for development of projects concepts and operation. Possibility to share funds for community workshop costs in order to allocate money for implementation of mitigation projects. • While Nukulaelae feels most of the disadvantages of isolation in common with the other outer islands it is nevertheless one of the closest outer islands to the international airport and support structures of Funafuti making it the most efficient in the context of operations in the outer islands. • The size of the population and the probable extent of identified mitigation projects for risk solutions make it ideal for a demonstration area for a project where funds are limited. • In relation to the possibility of working instead in the main island of Fongafale (Funafuti), which may have a slightly lower hazard potential as a result of cyclones, but a much higher risk, the following points have been noted: The funds available in the current project are inadequate to tackle the consultations with the eight different island groupings established and risk solutions required for the large population of Funafuti. For Funafuti there are other disaster-related projects/programs in place (SOPAC EU, AusAID waste project with continued funding from EU EDF 9, etc.) and generally the main islands are usually better supported.
1 Nukulaelae has a population density of 216 people/sq. km. compared to the average population density of 202 people/sq. km. for the 8 outer islands.
10 2.2 Population and Institutions in Nukulaelae
When the first missionaries came from Samoa, they arrived in Nukulaelae. At that time all the inhabitants of Nukulaelae reportedly lived on the biggest islet of the atoll, which they left later to choose the more vegetated Fagaua islet , which is about 1.2 km long.
According to the Census 2002, 68 houses are built on Nukulaelae with its population of 391 people (4.1 % of total population of Tuvalu). The community is divided into two settlements, namely, Nukualofa on the ocean side with 188 people (34 households) and Pepesala on the lagoon side with 205 people (34 households).
Old census data show a population increase on Nukulaelae (347 people in 1979, 315 in 1985 and 391 in 2002), although in the period between 1992 census and 2002 census about 1,000 people came to live on Funafuti and the population on the outer islands is decreasing.
Almost everybody in Nukulaelae (384 people) is a member of the national church (Ekalesia KelisianoTuvalu), only 7 people are members of the Bahai church. More women (54) than men (39) completed the secondary school as highest school level (total of 93), 183 completed primary school (91 men, 92 women) and 62 completed the old mission school as highest school level (27 men, 35 women).
The people of Nukulaelae make their living mainly on a subsistence basis with agriculture and fisheries. The main employer is the government besides income generated as seamen on international vessels and remittances from Tuvalu residents living overseas. Almost every family has a member in the local dancing group that earns money with performances in Funafuti and elsewhere.
The local government is made up of the Kaupule with 6 members elected by the population of Nukulaelae and administrative staff like planners, secretaries and treasurers. The Pule Kaupule is the head of the Kaupule. Recurrent revenue for local government and its Kaupule Trust Fund is mainly provided by government grant, taxes and trading services and was AUD$10,000 for Nukulaelae in 1992 (Reynolds at al, 1993). Due to the limited resources capital expenditure is mainly financed by external foreign aid usually with a self-help component involving free local materials such as sand, aggregates and timber and possibly unskilled labour. The Kaupule calls for community work which will be carried out by the male population with food provided by the women. Buildings are usually provided under aid programs as office, workshop, guest house, primary school and community training centre, health clinic and hospital wards.
11 Some national bodies are permanently represented on the outer islands with a manager of the Community Fishing Centre (CFC), one Agriculture Extension Officer and a representative of the Tuvalu Copra Corporation Society (TCCS). A Disaster Committee chaired by the Pule Kaupule consists of all government representatives; nurses, teachers, doctors, police, Telecom etc., all together about 10 people.
The community of Nukulaelae is further represented by the traditional system, having an island chief, the Ulualiki, and one village chief of each of the two villages, the two Takitakis. Reportedly, the community is about to start its own community fund. There are several active groups in the villages like the Youth Groups (1 in each village), the Womens Organization (with 1 sub-group in each village), the Sports Group (1 in each village) and the Red Cross. The community is said to be strong and well organized with examples given that liquor and dogs had been banned by the Kaupule, pigs and chickens are only raised on other unpopulated islets, and Nukulaelae was the first outer island with a considerable number of concrete houses and with electricity.
2.3 Felt disaster vulnerability and preparedness
The women from Nukulaelae recalled the Hurricane Bebe in 1972 as the most severe natural disaster experienced in their life-time. Houses collapsed as well as many trees and banana plants, a few people had been injured. This cyclone was followed by Cyclone Ofa in 1990, Cyclone Hina in 1993 and another in1997. As most of the buildings are now made of concrete, collapses of houses are of less concern than the fixing of roofs (see 3.1 Housing).
Waves during cyclones but also flooding during king tides in February and March are seen as a major threat by the women from Nukulaelae. Seawater at times over-tops the natural coastal levees as well as intruding as saline groundwater. The waves sometimes overflow the island at its most narrow site. They affect the pulaka pits (see 3.2 Agriculture and Fisheries) and the use of groundwater. The women consider the situation worse now probably because of the increased erosion by beach sand mining due to growing population and the need for cement for building modern concrete houses (see 3.3 Erosion).
When a cyclone is forecast, the Disaster Committee of the island meets. They call men to help with disaster preparations in the village, e.g. to cut down trees close to houses, to cover windows of unfinished new houses and to fence them with coconut leaves. The families store kerosene, a torch, water and food inside the houses.
12 A big problem for Nukulaelae is the lack of communication with Funafuti. Both Nukulaelae and Niulakita frequently lose radio contact. The Telecom system has not been working for about one year now and needs repair. Additionally, the need for a back-up system like a high frequency (HF) radio system was expressed.
Droughts were reported in 1974 with the most severe in 1990. In 1977 and 1985 Tuvalu experienced severe rain shortages (Butler, 1994). However, drought conditions occur in most years, although usually for a relatively short period, and threaten the water supply for the people of Nukulaelae (see 3.4 Water-supply). The women said that they prepare for water shortages and droughts by conserving water, educate their children in conservation of water and bathe in the sea during the period of water shortage. Pits (about 1 m deep) are dug in order to harvest groundwater with buckets for the use of animal feed and washing. In times when only very little drinking water is available they drink more coconut juice.
The Intergovernmental Panel on Climate Change (IPCC) predicts that there will be a 10-30 cm rise in sea-level by the year 2030 and 30-100 cm by the end of the 21st century (http://www.sopac.org.fj). The potential sea level rise would affect all the areas described below and is therefore not discussed as an additional topic and was hardly mentioned by the interviewees during the various conversations. Given sea-level, rise erosion would be expected to worsen and require more extensive and expensive coastal protection works. The ground water lens would rise. As the land area would have diminished due to flooding the lens volume would decrease and salinity levels would change. As a result pulaka pits will have to be raised or new methods found for them to be drained or irrigated, and vegetation will be less viable due to water-logging and/or greater saline concentrations. There could be a need to change wood and crop species appropriately (Reynolds et al., 1993). Pit latrines, septic tanks and refuse tips would all be affected. Their discharges would be more likely to lead to pollution of groundwater than at present and so have an effect on the consequent use of that water (see 3.5 Sanitation).
13
3. Disaster-related Problems and Potential Solutions in Nukulaelae
3.1 Housing
Different views have been expressed about the quality of fixing of the roofs of buildings in Nukulaelae: The Nukulaelae dancing group funded roof fixing for a considerable amount of roofs, the others are fixed with Pandanus (Filipo Taulim, Director of Works, Energy and Communications). But according to Rt. Hon. Bikeni Paeniu, Minister for Finance, Economic and Industries, the roofs are not cyclone-proofed and he hopes that the new Strategic Plan to be elaborated on the National Summit in June 2004 will include the legislation and enforcement of a building code.
A traditional house opposite to the house of the Prime Minister in Funafuti was built, but Enate Evi, Environment Office expressed some doubts that people would want to copy traditional cyclone proof houses nowadays. He also doubted whether they would go to an evacuation house, or rather stay at their own houses in case of a cyclone emergency.
3.2 Agriculture and Fisheries
As on each island throughout Tuvalu, the people from Nukulaelae also grow pulaka (Cyrtosperma) and taro (Colocasia) in pits cut into the limestone base of the atolls to compensate for poor soil. The pulaka pits have been excavated to the level of the water table and the resulting spoil dumped around the edge to give an elevated rim above the level of the surrounding land. In the pit, organic material from shrubs, creepers and ferns are mixed with sand from the pit floor. The resulting artificially constructed soil is a dark organic muck (sandy loam) that does not usually have much profile differentiation. The break between growing medium and substrate is usually sharp with the substrate being compacted rather than loose. Soil bulk density is low and organic content high (Reynolds et al., 1993). Spoil banks have varying proportions of sand and gravel that has been dumped during excavation. The profile consists of a thin organic litter layer, a few centimetres thick overlying the stained sand and gravel that usually extends broadleaf trees grow on the bank providing shade for the crops and cultivator.
Pulaka and taro do not tolerate saltwater, either from changes in groundwater and the sea breeze, and in recent years more and more pulaka growers have been noticing that their tubers
14 have been rotting in the ground because seawater has seeped up into the pits. Several options to overcome the problem of increasing salinity have been discussed, like cementing the bottom and sides of this pit to prevent the seawater coming up or adding sand to the pits in order to build a wall against the breeze. As tested on other islands soil can be built in large mounds up to 10 m. Fagaua had a seawall to protect pulaka pits, which fall apart, as most of the seawalls did in Tuvalu.
Other plants grown in Nukulaelae are coconut trees, breadfruit, banana (Musa), sugar cane (Saccharum), sweet potatoes (Ipomea), pawpaw (Carica) and cassava (Manihot). The crops sold in shops are all imported like onions, garlic and carrots.
Cultivators sell copra to the TCCS, represented on their island, for about AUD$2/kg. Coconut wood is used for pig fences and housing. Support for cultivators is given by the Agriculture Extension Officer by selling seeds and NPK fertilizer to them. Aid projects tried to introduce vegetable gardens and provided seeds and tools, but after the first growth cycle no follow-up is given by the families.
In 1998 Nukulaelae started an apiculture (1 apiary in Nukulaelae, 5 in Vaitupu). In 1989 the annual yield per hive on Vaitupu was about 18.8 kg giving an income of AUD$17.
In Nukulaelae pigs and chicken are raised on the unpopulated islets. According to the Agriculture Department no diseases are known and no veterinarian service is available.
Each island has a Community Fishing Centre (CFC). Its manager buys fish from locals and processes fish on the islands (salt, dry and freeze in Nukulaelae). As the financial capability is limited, no technical or financial assistance is given to fishermen. CFC doesn’t give license to fishermen, but plans to do it in the near future (Sautia Malua, Director of Fisheries Department). Selling between families is no tradition; fish caught with a net is free. Only fish caught with using a boat are sold to other families because of the cost implications.
No steady decline of fish can be reported, but ups and downs. Nukulaelae has good reef fish. Some periods of the year people are not allowed to fish in the conservation area, which is controlled effectively by the Kaupule.
15 3.3 Coastal erosion
Unmanaged sand mining in Tuvalu has led to coastal instability resulting in reef degradation and impingement on fisheries. Chronic coastal erosion can also lead to the loss of coastal lands and infrastructure. Even though mining of sand from beaches is banned, insufficient enforcement of laws has led to poor management of the beaches. SOPAC has proposed a beach-profiling and monitoring programme for Niutao and Nukulaelae and proposes to examine alternative sources of aggregates through geophysical, bathymetric and sediment surveys in Nukufetau and Vaitupu.
A beach-profile and bathymetric survey was carried out by SOPAC in 1984 to assist in the identification of problem areas along the shoreline and provide estimates of seasonal sediment transport. Several studies have been undertaken on the various atolls of Tuvalu to address coastal erosion, sand transport and sedimentation in order to improve coastal management. These consist of studies in Vaitupu and Nukulaelae (1993), Fongafale (1995), Amatuku (1996) and Nukufetau (1996).
The women of Nukulaelae spoke about beach erosion due to sand mining. The population growth and increased building of modern cement houses increased the need for sand. The women believed that a sand mining law is needed for Nukulaelae. The sand could be exclusively taken from other islets of the atoll. Local people could be educated in coastal management through workshops and field training.
According to Rt. Hon. Bikeni Paeniu, Minister for Finance, Economic and Industries, and the womens representatives from Nukulaelae, the community wants a new seawall with concrete blocks against erosion. But instead of reducing erosion problems, seawalls in Tuvalu have worsened the effects of erosion and are not likely to be funded (Poni Faavae, Coordinator of NAPA in Tuvalu). Soft structures which absorb wave energy and tree planting are said to be more suitable for erosion control. For example the Tuvalu Council of Women had a NZAID- funded tree planting project on Niutao with exclusively local species like Calophyllum inophyllu and Pandanus species.
The NZAID Reef Channel Project blasted a new channel in Nukulaelae to improve the access for boats. There is a view that there are still rocks to be removed to improve navigation, but an assessment showed that the removal would change the flow characteristics and is therefore not considered to be suitable.
16 One answer to increased erosion and impacts of sea-level rise could be the relocation of part of the village as suggested by Rt. Hon. Bikeni Paeniu, Minister for Finance, Economic and Industries.
3.4 Water supply
Groundwater is very limited on the atolls of Tuvalu, surface water doesn’t exist. A lens of freshwater floats on seawater with a transition zone of brackish water. The groundwater that is available serves in the main the natural vegetation and crops grown in the pulaka pits and elsewhere. Abstraction for human and other uses is small and is used for livestock, washing clothes and bathing. In 1993 the groundwater area on Nukulaelae was measured with 0.032 sq. km. on Fagaua, 0.023 sq. km. on Central Fenualango and 0.15 sq. km. on Northern Tefakai (Reynolds et al., 1993).
The majority of islands have wells. Some are just holes dug down to the groundwater lens and are not protected from contamination and pollution. However within the villages most wells are protected by coral stone walls, capped and provided with hand pumps (diaphragm type) with latrines often adjacent. Groundwater is susceptible to pollution from sewage effluents, manure of animals grazing over groundwater supply areas, solid waste disposal due to limited land area and salt-water intrusion. The poor quality of tanks, dirty roof catchments and gutters, poor filters on tank inlets and absence of taps all lead to major threats to water quality. All water must be boiled before drinking. The population of Nukulaelae seems to be aware of the water quality problem, as waste is collected regularly, animals are raised on unpopulated islets and dogs are banned from the island. Groundwater on Nukulaelae seems to be harvested only during droughts for pigs and for washing.
A workshop on technologies for maximising and augmenting freshwater resources in small islands was held at the Secretariat in 1996. This workshop contributed towards a Source Book of Alternative Technologies for Freshwater Augmentation in Small Island Developing States to be published by SOPAC in a user-friendly format for application by water sector managers and planners in developing countries like Tuvalu.
In the early 80´s SOPAC assisted in the construction of 450 ferro-cement tanks associated with small areas of roofing sheets and gutters providing the catchments and shelter for an external kitchen area under the United Nations Community Development Fund Water Supply (UNCDF) Project with a total capacity of 640,000 gallons (2,880 cu. m). This project
17 provided most households with access to freshwater supply capable of lasting through extended periods of drought. Community storage tanks (two communal tanks of 1,200 cu. m. in Nukulaelae) have also been provided for use in dry spells. The household tanks had an approximate capacity of 3.6 cu. m. and were intended to meet drinking water demands, based on being 6 people in a family. However, once supplied, usage was generally extended and the available water used quickly. A contributory factor was the limited catchments supplying the tank as it was of the order of 9-12 sq. m. The adjacent house at that time normally had a roof of pandanus thatch and the run off was (and still is) not acceptable for personal use (Reynolds et al., 1993).
Following periods of experienced rainfall limitations in Tuvalu for weeks and months in 1985 and 1986 it was necessary to ration public water supplies and the government set out a water storage policy. In 1986 the Government’s policy for waters supply and storage was developed.
The basic guidelines for Nukulaelae were as follows:
• 2.25 cu. m. per person storage for the house (tank) • 0.75 cu. m. per person storage for the community (cistern) • 45 cu. m. days storage, at 50 litres per day per person for the house (tank) • 15 cu. m. days storage, at 50 litres per day per person for the community (cistern) • 60 cu. m. in total at 50 litres per day per person • 3.0 sq.m. roof area per cu. m. of storage essential, 4.0 sq.m. desirable
Another aid project was providing additional catchment area of about 22 sq. m. to 230 houses in Tuvalu. Today almost each household in Nukulaelae has two tanks with taps outside houses with about 1,500 gallons (6,750 litres) each (estimated by Petueli Noa, Youth Officer of Kaupule Nukulaelae). The material of the second has to be verified but might be hollow concrete blocks filled and rendered with cement mortar, or fibre glass. These are usually bigger than the ferro-cement tanks and range from 9-18 cu.m. and are associated with houses with metal sheet roofs (1 cu. m = 1,000 litres)
The women from Nukulaelae are worried about the water shortage during limited rainfall for 3-5 month each year. The public water system emergency tank of 500 gallons (2,250 litres) is damaged with several leakages and needs to be repaired. However, Filipo Taulima, Director
18 of Works, Energy and Communications argues that people on Nukulaelae don’t need the public tanks, as they have enough tank capacity at their houses and hence no water supply problem.
In 1990 two small Reverse Osmosis Desalination Plants were flown in for Funafuti. Desalination run by the Tuvalu Electricity Corporation (TEC) was meant to put on as an standby regime. But now trucks provide the desalinated water every day, the plants run the whole year, for families relying on desalinated water. It is subsidized by the government with a price of about AUD$15/1,000 litres (Kelesoma Salea, Coordinator of IWP).
There are small desalination plants on Vaitupu (school) and on Nanumaga. On Vaitupu a standby pump is used to pump up groundwater (Kelesoma Salea, Coordinator of IWP).
As a preliminary conclusion there seems to be the need for increased awareness on water conservation throughout the year for the families. Training of a plumber for Nukulaelae in all aspects of rainwater collection systems, e.g. adequate fixing and grading of gutters, appropriate use of PVC priming fluid and solvent cement for PVC pipe and fitting joints could be useful.
3.5 Sanitation
A few households do have flush toilets, the other toilets are flushed with water buckets. The households discharge sewage into latrines, problems with groundwater pollution in Nukulaelae have not been mentioned. The situation has to be discussed and clarified during the community workshop. The box below describes sanitation problems in Funafuti with the ineffective use of septic tanks and pit latrines. Composting toilets might be an interesting option also for the population in Nukulaelae as they give several potential benefits: savings in rainwater because no water for flushing is needed, protection of groundwater, simple technology and low costs.
With Funafuti’s increasing population major threats for the groundwater quality in Fongafale are the non-professionally built septic tanks. The pilot site of the International Water Program (IWP) is close to the IWP office in the North of Funafuti, and embraces 150 houses with
19 septic tanks and latrines. They are regularly flooded during king tides, which occur two to three times a year in February, March and September and flood up to a quarter of the island (including the borrow pits). Houses close to the hospital are even flooded after heavy rainfalls due to the big catchment and the overflow of rainwater tanks at the new hospital. The septic tanks leak, the outlets are flooded and overflow.
Septic tanks do not perform effectively in the atoll environment. Nutrient-rich waste is quick to enter the groundwater because of the porous nature of the soil and the high water table. They are often not built correctly by the house owner, although the Works Department provides brochures on how to construct them. The bacteria are washed into the sea and are sucked back by the desalination plant into the drinking water.
IWP considers choosing one of three solutions (Kelesoma Salea, Coordinator of IWP): Either (1) the construction of a reticulated system which seems to be quite vulnerable as the whole systems relies on the functioning of a pump, (2) the repair of all septic tanks or (3) the introduction of composting toilets: The pilot composting toilets are built 2 storeys high with a drum on a concrete slab, so that the out-take is high enough not to be flooded. The toilet has to be accessed by steps, which might be too exposed to be culturally acceptable.
Other serious problem are caused by the chemicals from the hospital entering the groundwater, as well as disposal of oil with PCBs from transformers and the flooding of waste-oil wells at the main power generator during king tides.
Signs of contamination are, amongst others, the occurrence of algae bloom in the north of Fongafale at the lagoon shore (green algae) and blue-green algae at the borrow pits. After the severe drought in 1990 Tuvalu suffered a serious cholera outbreak.
The hospital has a small pathology laboratory for standard microbiological testing. SOPAC has assisted Tuvalu in improving its water-quality testing programmes and sanitary practices.
3.6 Solid Waste
Each family in Nukulaelae has a rubbish bin. The Kaupule collects solid waste each month, uses a shredder machine and burns it. No waste problem was reported with tidal flooding as the bins stand on high ground. The organic waste is used by the families for gardening. Aluminium cans, considered as the “number one litter problem at the atoll of Funafuti”, are no longer a problem on Nukulaelae due to the liquor ban.
20
4. Preparation of Workshops in June 2004
4.1 Proposed Time schedule for June/July 2004
21 Mon 10.45 am Arrival at Funafuti June 12.00 am Meeting with SOPAC National Rep, Coordination NDMO and Secretary to Government 3.00 pm Meeting with NDMO, TANGO, TRCS, Workshop organization NAPA and all facilitators 22 Tues 8.30 am Meeting with all facilitators Methodology for Community Workshop 2.00 pm Meeting with Secretary of Finance Discussions on proposed integration of Project with National Summit 6.00 pm Boat transport to Nukulaelae 23 Wed 9.00 am Meeting with Kaupule, Nukulaelae Introduction to Workshop, Workshop organization 11.00 am Community Meeting Beginning of Workshop: Introduction and Organization 3 pm Walk through island 24 Thu 8.30 am Community Meeting (Plenary) 9.00 am Working Groups 12.30 amLunch 2.00 pmWorking Groups 3.00 pm Presentation of Working Group Results to Plenary 25 Fri 8.30 am Community Meeting (Plenary) Organize Working groups 9.00 m Working Groups 12.30 amLunch 2.00 pmWorking Groups 3.00 pm Plenary Presentation of Working Group Results to Community 7.00 pm Social function with Community 26 Sat 8.30 amPlenary 9.00 m Working Groups 12.30 amLunch 2.00 pmPlenary Presentation of Working Group Results to Community, Plan of Action, Further Steps
21 6.00 pm Boat transport to Funafuti 27 Sun Preparation of Multistakeholder Workshop, presentation, draft project profiles 28 Mon 2.00 pm Presentation to Summit? Presentation on project approach (1 hour) (SOPAC to explore) 29 Tues 9.00- Multi-stakeholder Workshop at Summit Presentation of workshop 12.30 am results by community of 1.30- Nukulaelae, finalization of 4.00 pm project profiles 30 Wed 9.00- Multi-stakeholder Workshop at Summit finalization of project profiles, 12.30 am definition of project 1.30- implementation structure 3.00 pm 3.00 Presentation to Summit? Presentation of project profiles (results of multi-stakeholder- workshop) to Summit (SOPAC to explore) 1 Thu 8.30 Meeting SOPAC National Rep, Evaluation of approach and July Secretary to Government, NDMO, definition of further steps TANGO, TRCS, NAPA 2 11.30 Departure
For transport to and from Nukulaelae the NDMO plans to arrange the hire of the patrol boat for Tuesday 22nd of June at 6.00 pm to Nukulaelae and for Saturday 26th of June back to Funafuti. The costs will be shared by the project and the disaster preparedness program of TANGO/FSPI.
The Minister for Finance, Economic and Industries, Rt. Hon. Bikeni Paeniu, invited the project team to take part in the National Summit from Monday 28th of June until 9th of July as resource persons. SOAPC is following up on this issue with authorities in Tuvalu. At the end of March the consultation process on the outer island supported by NZAID will start. Donors such as NZAID, AUSAID and UNDP are already committed to draft the Strategic Plan. On Monday 28th of June, the first day of the summit, approaches and methodology of the island consultation process will be presented.
It will be a potentially good opportunity for the project to integrate the planned multi- stakeholder workshop in the program of the National Summit. The major donor agencies will be present and costs can be saved because island representatives are already invited to the Summit and don’t have to be sustained during the workshop in Funafuti by the project. The
22 coordination with the National Summit would be made through the Secretary of Finance, Mr. Seve Painu.
4.2 Workshop Facilitation Team
After having analysed the disaster-related programs and activities in Tuvalu (Figure 2) a suitable team to facilitate the community workshop and the multi-stakeholder workshop in June 2004 could be set up (Error! Reference source not found.The workshop facilitation team ideally would be composed of SOPAC, the NDMO, TANGO, the Tuvalu Red Cross Society and possibly the NAPA program. A suggestion was that the Director of Works, Energy and Communications Filipo Taulima second a resource person from his department to the community workshop. However, the Disaster Coordinator Sumeo Silu, who worked at the Department of Works, Energy and Communications before, would handle that role, providing technical insight to the relevant working groups in the community.
The National Disaster Management Unit works directly under the Secretary to Government. The Secretary to Government is the overall controller of disaster events and chairs the National Disaster Committee (NDC). The NDC is comprised of the Secretaries of all Ministries and is the decision-making body. It has appointed the National Disaster Preparedness Working Group (NDPWG), consisting of government and non-government organisations, to design, develop and implement disaster mitigation and preparedness programs and activities. In case of a disaster event the Island Operation Centres (IOC) chaired by the Police are in charge of the operation. The Disaster Coordinator Sumeo Silu takes part in the workshops and functions as the local overall coordinator of the workshops.
The Tuvalu Association of NGOs (TANGO) is a community-based organization, whose principal concern is encouraging and assisting NGOs in their work to enable human development within Tuvalu. TANGO’s goals and objectives are, amongst others, to improve the capacity of NGOs and CBOs (Community Based Organization) leaders and workers to effectively carry out their roles and responsibilities and to increase cooperation, coordination and networking between NGOs donors and governments operating in Tuvalu and the region (http://www.fspi.org.fj/affiliates/tuvalu.htm). TANGO is affiliated with the South Pacific umbrella NGOs PIANGO and FSPI. FSPI is a network of South Pacific island non- governmental organisations and overseas affiliates working in partnership across the South
Program Implementing Donor Duration Funding options for Agency mitigation projects
23 Pacific Disaster FSPI, TANGO AusAID 5/2003- Awareness, training, Preparedness 6/2004, 2nd disaster management Program phase for another year
International Dept. of AusAID? 5 years (since Water supply mitigation Water Program Environment 2 years) projects, sanitation projects, (IWP) waste
National Dept. of UNDP/ GEF Jan-Dec.2004 Adaptation Environment Program of Action (NAPA)
Reducing SOPAC EU EDF 8, Awareness, training, Vulnerability of disaster management, Pacific ACP studies, communication, States water supply, sanitation, waste management, erosion control and agriculture, roof fixing
NZAID various NZAID In the middle Training, Water, Regional of 5 years Environment. Applications Environment plan, this to Suva Program year planning for 2nd phase
NZAID Small NZAID Ongoing Up to 5000 AUD for Grant Fund training, water and environment. Applications
to Funafuti
Climate Change Lands and AusAID in phase 3 Studies (e.g. DTM), contact and Sea-level Survey Dept., Susan Ivatts in Suva office Project Flinders University
Taiwan (ROC) Government Taiwan Infrastructure, home Bilateral organisations (ROC) gardening, standard of Projects living, economic development
Food Insecurity Dept. of FAO Agriculture, erosion control Vulnerability Agriculture Project (FIVMS)
Figure 2: Disaster-related programs in Tuvalu and potential for the implementation of mitigation projects
24
Graham Shorten SOPAC (Consultant)
Susanne Schmall SOPAC (Consultant)
Sumeo Silu NDMO (Disaster Coordinator)
Lilian Falealuga Tuvalu Red Cross Society (Director)
Tom TANGO (Training Officer)
? NAPA
Petueli Noa Youth Officer Kaupule Nukulaelae (former Tuvalu Red Cross Society disaster preparedness trainer)
Figure 3: Facilitation team for community and multi-stakeholder workshop
Pacific. The main function of the FSPI Secretariat is to coordinate the planning and design of regional development projects, based on the needs identified by the members and their constituencies (http://www.fspi.org.fj/). Since May 2003 FSPI runs the Pacific Disaster Preparedness Strengthening Program in nine Pacific Island Country States (PICS) with a budget volume of AUD$250,000. Tuvalu chose Nukulaelae as a pilot area, funds are planned mainly for disaster awareness raising and training. During this mission in Tuvalu it was tentatively agreed to carry out the community workshop together and to share some of the costs.
The Tuvalu Red Cross Society (TRCS) exists since 1981 and is in a redefinition process after having appointed the new director Lilian Falealuga in January. She will take part in the workshops.
Three of its eleven branches are based on Funafuti, eight on the outer islands. The TRCS has the mandate for relief from the Tuvalu Government as the only NGO within the NGO- network TANGO. They work on relief supply and preparedness and run an HIV program. They have one container with relief supply items and receive 3 times a year second-hand clothes for emergency distribution.
The organisation receives most of its funds from the Red Cross organisations of Japan, USA, and Australia, and from UNESCO. Identified mitigation projects of this project could be forwarded to them in order to seek support.
The National Adaptation Programmes of Action (NAPA) have been established to address the urgent and immediate national needs of Least Developed Countries (LDCs) for adapting to
25 the adverse impacts of climate change and for preparation of National Communications to the UNFCCC. UNDP supports the LDCs and small island developing states (SIDS) in the development and implementation of NAPAs and ensure that NAPAs build on existing national programmes. The interventions focus on reducing vulnerability and promoting adaptation to climate change as well as on mitigating climate change. Five LDCs in the Pacific have been selected , namely Kiribati, Samoa, Solomon Islands, Tuvalu and Vanuatu.
The NAPA of Tuvalu was approved by the GEF Secretariat in February 2003. However due to problems in appointing staff the program started 6 months too late in January and will be finished in December 2004. In April they are going to consult the outer islands in order to develop project profiles and the budget. Funds can than be allocated to disaster awareness programs. Then the leaders of the islands will meet in Funafuti and prioritise mitigation projects, which will be submitted to the LDC-Fund of UNDP and are very likely to be funded (USD$1 M is available for the Pacific: Poni Faavae, Coordinator of NAPA in Tuvalu). As the consultation process at the outer islands seems to be similar to the approach of this project, requests for funding for mitigation projects could be forwarded within the NAPA procedures. We suggested it might be beneficial to work together and that NAPA should consider sending a facilitator for the community workshop in June.
4.3 Participants for the Workshops
The following participants are proposed for the Community Workshop in Nukulaelae and the Multi-Stakeholder workshop in Funafuti and will be invited by the NDMO.
Participants for Community Workshop in Nukulaelae
• Kaupule (6 members) • Ulualiki (1 island chief) • 2 takitaki (1 village chief of each village) • Disaster Committee (including the Community Fishing Centre, the Agriculture Extension Officer, the Tuvalu Copra Corporation Society , Police, Telecom, Red Cross etc.) • Church representatives • Youth groups from both villages • Womens groups of both villages • Sports group of both villages
26
Participants for Multi-Stakeholder Workshop in Funafuti
• Lutelu Faavae Ministry of Natural Resources and Lands, Secretary, National Representative of Tuvalu to SOPAC • Annie Homasi TANGO Coordinator • Tom TANGO Training Officer • Elu Director of Agriculture • Enate Evi Environment Officer • Filipo Taulima Director of Works, Energy and Communications • Hellani Tumua Administrative Officer, AusAID Office • Hilia Vavae Director, Meteorological Office • Kelesoma Salea IWP Coordinator • Kulene Sokotia Acting Director of Lands and Survey • Lilian Falealuga Tuvalu Red Cross Society • Michael P.Y. Hsu Chargé d´Affaires, Embassy of the Reuplic of China • Panapasi Nelesone Secretary to Government • Pasemeta Sateko EU-NZAID In-Country Coordinator Talaapa • Petueli Noa Youth Officer Kapule Nukulaelae • Poni Faavae NAPA Coordinator • Rt. Hon. Bikeni Minister for Finance, Economic and Industries Paeniu • Sumeo K. Silu NDMO Disaster Coordinator as well as the representatives of Nukulaelae present at the National Summit in Funafuti.
4.4 Budget for Community Workshop and Multi-Stakeholder Workshop
An estimated budget for the two workshops was discussed and a preliminary distribution of costs between the project, TANGO, TRCS and NDMO tentatively agreed on pending further discussions.
4.5 Potential mitigation options to emphasize on at the workshop
1. Improvement and protection of pulaka pits 2. Housing: roof fixing
27 3. Water supply: Awareness for water conservation, reparation of public water tanks, plumber training, increased rainwater catchments for houses 4. Sanitation: composting toilets, construction of septic tanks 5. Erosion: Tree planting , management of sand mining, seawall construction 6. Disaster awareness, training and management 7. Communication (reparation of Telecom service, purchase of High Frequency radio units as a back-up system) 8. Partial relocation
4.6 Next Project Steps for the Workshop Preparation
• Send project summary information paper of March mission to SOPAC National Rep, NDMO, Secretary to Government, Tango, Red Cross, NAPA, FSPI and Secretary of Finance (by Project) • SOPAC to clear generic information paper for Sumeo on mitigation projects to pass to Secretary and then to DCC (for DCC Meeting of April) (by Project) • SOPAC to clear preparation of information paper for Sumeo on aerial photos and DTM to pass to Secretary and then to DCC (for DCC Meeting of April), should include provision for technical training (Sumeo’s point) (by Project) • Draft 1-2 pages introduction into the project and the workshop in English for the invitation in Nukulaelae (by Project), translation into Tuvaluan (by TANGO) • Advertise workshop on radio, explain approach to clarify the separation between the Project approach and the approach of NZAID and the TNA (Tuvalu National Assessment) team to prepare the National Summit (by NDMO and Home Affairs) • Prepare awareness material for workshops based on numerical modelling of cyclone effects on Nukulaelae and Funafuti in particular • SOPAC through National Rep to explore feasibility of integration of Funafuti multi- stakeholder workshop into National Summit of Monday 28th June – 9th July, coordination with Secretary of Finance, Seve Paeniu • Book hire of patrol boat for Nukulaelae (by NDMO) • Obtain report on NZAID Reef channel project on Nukulaelae (by SOPAC and Project)
28 Appendix 1: Resource Persons and Organizations contacted
Name Organization Function Contact
Lutelu Faavae Ministry of Natural Resources & Permanent [email protected] Lands Secretary, National [email protected] Representative of Tuvalu to SOPAC
Annie Homasi TANGO Coordinator [email protected]
Dawn Tuiloma- Foundation of the Peoples of the Regional [email protected] Paleso'o South Pacific International (FSPI) Programme Manager – Disaster
Elu Department of Agriculture Officer
Enate Evi Department of Environment Evnironment Officer [email protected]
Esi, Malia, Women from Nukulaelae and head Liliane, Lola, of Nukulaelae womens Tusiata organization
Fakavae Taomia Ministry of Home Affairs Secretary for Home Affairs
Fanoanoaga former Director of Patolo Lands & Survey
Filipo Taulima Works, Energy and Director Communications
Hellani Tumua AusAID Office Administrative [email protected] Officer [email protected]
Hilia Vavae Meteorological Office Director [email protected]
Hon. Samuelu Ministry of Natural Resources & Minister [email protected] Penitala Teo Lands
Kelesoma Tauia International Water Program Coordinator [email protected] (IWP)
Kulene Sokotia Department of Lands & Survey Acting Director
Lilian Falealuga Tuvalu Red Cross Society Director Tel: (688) 20746 / 20740 Fax: (688) 20800
Michael P.Y. Embassy of the Republic of China Chargé d´Affaires [email protected] Hsu [email protected]
Panapasi Office of the Prime Minister Secretary to Nelesone Government
29 Pasemeta Sateko NZAID / EU In-Country [email protected] Talaapa Coordinator
Petueli Noa Kaupule Nukulaelae Youth Officer [email protected]
Poni Faavae National Adaptation Programmes Coordinator [email protected] of Action (NAPA)
Rt. Hon. Bikeni Ministry of Finance, Economic Minister Paeniu and Industries
Sautia Malua Department of Fisheries Director
Sumeo K. Silu National Disaster Management Disaster Coordinator [email protected] Unit, Office of the Prime Minister 688 20128
Russell Howorth SOPAC Deputy Director [email protected]
Alan Mearns SOPAC Community Risk Program Manager [email protected]
Stephen Booth SOPAC EU-Program Reducing Coordinator [email protected] Vulnerability of Pacific ACP States
Franck Martin SOPAC ICT Specialist [email protected]
Noud Leenders SOPAC Community Risk [email protected] Management Adviser
Robert Smith SOPAC Marine Geophysics [email protected] Senior Adviser
Graham Shorten Environmental and Community SOPAC Consultant [email protected] Risk International Pty Ltd (ECRi) .au
Susanne Schmall Workshops Coordinator and SOPAC Consultant susanneschmall@compuse Facilitator rve.de
Appendix 2: Documents reviewed
Butler, Ron (1994): Tuvalu: Domestic Water Resource. Waste Disposal. Australian Executive Service Overseas Program (AESOP) Falkland, Tony (1999): Water Management for Funafuti, Tuvalu. Australian Agency for International Development (AusAID) Opus International Limited (1998): Funafuti, Tuvalu, Solid Waste Management Plan. SOPAC Joint Contribution Report 118. Tuvalu Government (1997): National Disaster Plan Reynolds, C., Eng., B., Eng., C., MICE, MIWEM: Tuvalu Water and Sanitation Plan for Period 1993-2002.
30
PART 2 – SECOND MISSION, JUNE 2004
Taiwan-ROC funded project
Building Capacity to Insure against Disasters in Pacific Island Countries (Tuvalu)
South Pacific Applied Geoscience Commission (SOPAC)
Project Duration: February-July, 2004
Report on Second Mission
21st June – 1st July, 2004
“Disaster Vulnerability and Mitigation Workshop in Funafuti”
Dr Susanne Schmall
Geo-Ecologist, Community Adviser
Ebergoetzen, July 2004
32
1. Objectives and Workplan
During the first mission in March 2004 of the ROC-funded project “Building Capacity to Insure against Disasters in Pacific Island Countries (Tuvalu)” by the South Pacific Applied Geoscience Commission (SOPAC), institutional appraisals and workshop preparations were carried out and reported on in Schmall (20041). The current report summarizes the second mission to Tuvalu by Dr Graham Shorten and Dr Susanne Schmall commissioned by SOPAC from 21st June-1st July, 2004.
The main objective of this second mission was to carry out a community and multi- stakeholder workshop on disaster vulnerability and mitigation for the communities on the island of Fongafale in Funafuti atoll, Tuvalu. The workshop was held at the Vaiaku Lagi Hotel in Funafuti on 23rd-25th June, 2004 (see In-Country Work Program in June/July 2004, Figure 1). A detailed workshop report is attached as Annex 1, and a presentation to that workshop as Annex 2.
Following the analysis of the results of the workshop, proposals for risk treatment projects were drawn up and are detailed in Annex 3. Annex 4 forms a photo-documentation to that proposal. The proposals are based on the findings of the working groups, the earlier institutional appraisal, documents reviewed and further discussions with Government and non-government organisations. In order to promote the project proposals within the Government of Tuvalu and the donor community, contacts were made with various donor agencies and a presentation prepared for the National Disaster Coordinator, Sumeo Silu, to be held on the National Summit on Sustainable Development (NSSD) in July, 2004, in Funafuti (Annex 5). The report on the earlier groundwork carried out in March, 2004 in preparation for the workshop in July, 2004 is included as Annex 6.
1 Schmall, S. (2004): Institutional Appraisal and Preparation of Workshops. Report on First Mission (7-16th March, 2004) of the Taiwan-ROC funded project “Building Capacity to Insure against Disasters in Pacific Island Countries (Tuvalu)” commissioned by the South Pacific Applied Geoscience Commission (SOPAC), Ebergoetzen
33
21 Mon 10.45 am Arrival at Funafuti June 14.00 am Meeting with NDMO Disaster Coordinator Sumeo 22 Tues 9.30 am Lutelu Faavae (Permanent Secretary, Ministry of Natural Resources and Lands, National Representative of Tuvalu to SOPAC) 1.30 pm Meeting with facilitation team: Sumeo Silu (NDMO), Lilian Falealuga (Tuvalu Red Cross Society), Petueli Noa (Ministry of Home Affairs and Rural Development), Tom Hauma (Tango) 3.30 pm Meeting with Dr Feng Tai (Ambassador of the Republic of China) 6.30 pm Workshop preparation with Sumeo Silu 23 Wed 8.30 am Opening of Disaster Vulnerability and Mitigation Workshop 10.00 am Workshop 6 pm Workshop report writing 24 Thu 8.30 am Workshop 3 pm Workshop report writing 25 Fri 8.30 am Workshop 3 pm Closure and VB 5 pm Workshop report writing 26 Sat Workshop report writing Design of project proposals 5 pm Opening of National Summit on Sustainable Development (NSSD) 27 Sun Workshop report writing Design of project proposals 28 Mon Workshop report writing Design of project proposals 2.00 pm Meeting with Sumeo Silu 29 Tues Design of project proposals Photo documentation of mitigation project sites 30 Wed Design of project proposals 2.00 pm Meeting with Sumeo Silu 1 Thu 9.00 Meeting with Susan Tupulaga (Waste Management Office, Dept. of July Environment) 11.30 Departure
Figure 1: In-Country Work Program in June/July 2004
34 2. Conclusions
2.1 Workshop in Funafuti
During the first mission to Tuvalu planning was made for a community workshop in Nukulaelae on the vulnerability of Nukulaelae and the options for disaster mitigation. These plans could not be followed up due to transport problems: The official booking of the patrol boat to travel to Nukulaelae was cancelled in the first week of June due to unforeseen formal Government obligations for the boat at the scheduled time of the Nukulaelae workshop.
With the NDMO, Secretary to the Prime Minister’s Department and the National Representative to SOPAC in Tuvalu it was agreed to run the workshop on Funafuti instead, which is considered to be the most vulnerable island to disasters due to its location and high population density. As Funafuti is the capital with the most work opportunities and infrastructure of the eight Island communities of Tuvalu, Funafuti’s population not only embraces the original land-owners of Funafuti, but also an increasing proportion of its people originating in the Outer Islands. Each of the Island communities elects a community leader to represent their interests. These eight community leaders were invited to the workshop as well as representatives of the Government and non-Government organisations involved in work related to hazard assessment and disaster management.
Compared to the participation of the Government representatives, the involvement of the community leaders in the discussions was rather more limited. Community and Government are difficult to separate in Funafuti, and the results of a workshop held on an Outer Island would have been perceived as more community-owned than one in a complex society like Funafuti. A separate workshop after a community workshop exclusively for the Government and non-government institutions could not be arranged as in the second week of the mission the National Summit on Sustainable Development (NSSD) took place and absorbed the time of most of the representatives.
2.2 Co-operation with other disaster reduction programs
The project combines hazard assessment for a pilot area (Fongafale) as well as vulnerability assessment and community disaster mitigation planning in a selected community in Tuvalu. It is of vital importance for this project to integrate into the existing and planned activities in the field of disaster assessment; preparedness and relief by the Tuvalu Government, by non- government organisations and regional development programs. The project sought
35 cooperation with other programmes in order to combine strengths and to optimise the allocation of funds.
The joint planning effort on the first mission with the FSPI/Tango disaster reduction programme, which included sharing of workshop budget for the community workshop on Nukulaelae, was cancelled by FSPI. The cooperation was limited to the facilitation support of the Tango training officer to the workshop (which was, incidentally, much welcomed). Tango plans to carry out another disaster vulnerability workshop with the communities on Fongafale soon after the NSSD.
The Global Environment Facility (GEF)-funded National Adaptation Programs of Action (NAPA) will also carry out consultation workshops with each island community in order to address needs of the civil society with respect to climate change adaptation, and will hold yet another vulnerability and mitigation workshop in Funafuti. The coordinator of this programme took part in the current Taiwan-SOPAC workshop.
As the current SOPAC workshop failed to be recognised as one activity that could serve all three programs, it is no wonder that Government representatives and community leaders frequently complain about the time-consuming workshops with no compensations in the form of allowances.
2.3 Promotion of Project Proposals
During the first mission in March the Minister for Finance, Economic and Industries, Rt. Hon. Bikeni Paeniu, invited the project team to take part in the National Summit of Sustainable Development (NSSD) from Monday 28th June until 9th July as resource persons. However, SOPAC decided to send its own representatives to the NSSD instead.
As all representatives from senior positions of Government and non-government organizations as well as donor organizations were invited to take part in the NSSD, the project team had very limited chances to meet with these people for further discussions on the project proposals. However, final meetings with the NDMO, the Ambassador of Taiwan-ROC and the Waste Management Office did take place after the workshop was concluded.
A great deal of interest has been shown in the outcomes of the workshop by senior Government representatives and donors such as Taiwan-Republic of China and NZAID. In particular, the project proposals have been requested to be made available as soon as possible so new funding opportunities based around these proposals may be examined.
36
PART 3 – ANNEXES
Annex 1
Disaster Vulnerability and Mitigation Workshop, Funafuti Vaiaku Lagi Hotel, Funafuti, 23rd-25th June, 2004
Workshop Report
Dr Susanne Schmall
38
Republic of China
Disaster Vulnerability and Mitigation Workshop, Funafuti Vaiaku Lagi Hotel, Funafuti, 23rd-25th June, 2004 Workshop Report by Dr Susanne Schmall
1. INTRODUCTION
Project Leader Dr Graham Shorten described the genesis of the project and the objective, purpose and major outputs of the work. The SOPAC project “Building Capacity to Insure against Disasters in Pacific Island Countries (Tuvalu)”, funded by Taiwan-Republic of China, aims to improve the security and quality of life for the Funafuti communities at high risk from weather and climate-related disasters. He reminded the gathering that, although the major hazard from cyclone may remain relatively unchanged, the risk to the Funafuti community has increased dramatically over recent years as a result of increased exposure through growing population, infrastructure and housing, and increasing vulnerability as many traditional risk solutions are discarded. Better understanding of the cyclone hazard will be a first step forward in combating the risk of disaster from cyclone. After the collection and analysis of scientific data for a cyclonic wind and storm wave modelling, this participatory community workshop was organised in order to present preliminary scientific project results, to discuss the disaster vulnerability of Funafuti’s communities and identify specific risk-management solutions. The project will then transfer the outcomes of the working groups (the problem analysis and the Plans of Action) into project profiles, revise them with relevant Government and non-government organisations in Tuvalu and provide support to find suitable means and finance for their implementation. The timing of the workshop in the lead-up to the Tuvalu National Summit on Sustainable Development will be sure to help raise awareness of the issue of cyclone-related disasters in the country.
39 2. OPENING BY PRIME MINISTER HON. SAUFATU SOPOANGA
Your Excellency the Ambassador of the Republic of China to Tuvalu, Dr Feng Tai; Pule Fanua o Funafuti, Siaosi Finiki; Representative of the Ekalesia Kelisiano Tuvalu, Reverend Kautoa Moloti; Funafuti Pule Kaupule, Solomona Ielemia; SOPAC consultants, Dr Graham Shorten and Dr Susanne Schmall; Distinguished Secretaries, Directors, and Heads of Departments; Invited Guests, Ladies and Gentlemen. It is indeed an honour and a pleasure to welcome you all today at this opening of the community vulnerability and mitigation workshop, which will take place here over the next three days. Throughout the past year, SOPAC has been executing the project “Building capacity to insure against disasters in Pacific Island countries (Tuvalu)” with the assistance of consultants Dr Graham Shorten and Dr Susanne Schmall. SOPAC is the nominated centre for disaster management in the Pacific Forum countries and deals with a wide range of disaster-related projects in the region. This particular project has been funded by the government of the Republic of China, and we are deeply grateful for their generous support. I know that Taiwan – a country that itself suffers from a multitude of severe natural hazards - is keen that some real solutions to the risks of communities in Funafuti are found through this project. The people of the Tuvaluan communities on which this project is focussed are pleased to see that attention is now being given to their particular interests. Much of the population of Tuvalu is exposed to high risk because of the geography of its low-lying atolls and islands, and the ever-present threat of cyclones. The southern group, including Funafuti and Nukulaelae, are most at risk from damaging cyclones but there is no guarantee that any of the islands are completely safe. The Government of Tuvalu recognises that the continuing impacts of cyclones, large and small, are effectively bleeding the economy of the country, even without the impact of a direct hit from a highly destructive ‘super cyclone’. Records for the country are short, but Cyclone Bebe in 1972 remains as the standard by which all later events in the Pacific have been judged. It is not just the threats of storm surge, storm wave and cyclonic wind hazards that must be addressed, but also the vulnerabilities brought about by fluctuations in sea level, insecure water supplies and unsustainable waste management systems that all reduce the capability of communities to cope with natural disasters. The Taiwan Building Capacity Against Disasters project sets out not only to develop computer models to help the people of Tuvalu understand the erratic and dangerous behaviour of cyclones in their region, but also to lay out designs for specific project proposals that will assist Tuvalu communities to implement solutions to the risks that face them. I sincerely ask the participants of the workshop to focus on the task at hand to ensure that the outcomes will truly assist in reducing the risk to the community. The project proposals developed by the workshop should clearly identify practical activities that result in practical solutions to the problems posed by disasters. The project proposals should be relevant to the community and worthy of taking forward for funding by a donor. We can only pray that a committed donor - perhaps the same donor that funded this project and workshop - is able to reach deeper to find further funds for implementation of the very important risk-treatment solutions in this new environment of international cooperation. At this juncture, I now declare this workshop on community vulnerability and mitigation officially open.
Tuvalu Mote Atua.
40 3. OBJECTIVE OF THE WORKSHOP AND TEAM
Objective of the Workshop: Reduce future disasters by planning mitigation actions Participants: Leader of communities in Funafuti Government organizations Non-government organizations (NGOs) Output: Plans of Action for selected mitigation topics Workshop report Project proposals Resources: Need for community, government and donor inputs
Sumeo Silu NDMO, Coordinator Tom Hauma Tango, Training Officer Petueli Noa Ministry of Home Affairs and Rural Development, Youth Officer Graham Shorten SOPAC Consultant Susanne Schmall SOPAC Consultant
4. WEDNESDAY PROGRAM
Program of first workshop day 1. Opening remarks (MC: Sumeo Silu)
2. SOPAC-Taiwan Project (Dr Graham Shorten)
3. Opening (PM Hon. Saufatu Sopoanga)
4. Benediction by Ekalesia Kelisiano Tuvalu
Morning tea
5. Objective of the Workshop and today’s program (Dr Susanne Schmall)
6. Presentation of preliminary project findings (Dr Graham Shorten)
7. Disaster vulnerability of communities in Funafuti (Working Groups)
Lunch
8. Presentation of working group results
9. Prioritisation of mitigation topics
10. Time schedule for working groups on mitigation topics for next 2 days
41 Presentation of Preliminary Project Findings by Dr Graham Shorten
A number of large cyclones have been recorded in the vicinity of Funafuti. These cyclones usually intensify as they track southwards towards Fiji or Samoa. Recent research and modelling by Steve Oliver and Matt Eliot as part of this project has added greatly to the understanding of cyclones in this region and their preliminary findings were presented here. In 1972, Tropical Cyclone Bebe caused extensive damage and flooding in Funafuti: The worst effect of the accompanying storm surge was up to 0.5 m elevation of sea level at Fongafale as TC Bebe intensified and passed close to Funafuti. As the tail of TC Bebe moved over Funafuti, westerly winds forced up a bulge of the storm surge across the shallow waters of the eastern side of the lagoon. For at least a six-hour period, the water level in the eastern part of the lagoon was higher than the water level in the open ocean immediately to the east of the atoll. The maximum storm surge at Funafuti occurred close to low tide, to a large extent negating the effects of the surge. As the net storm surge was not very high, the impact of waves has also been examined to determine what their contribution might have been. While TC Bebe was still well north of Funafuti on 21st October, 1972 at 0300h UTC (local time 1500h on 20th October), wave heights near the centre were at about 4-5 m, with 3-4 m waves reaching Funafuti. At 1500h UTC on 21st October (local time 0300h) as Bebe approached Funafuti, the initial flooding of Fongafale occurred on the first high tide of the day. Waves reaching the island at this stage were now 5-6 m high. When the eye of TC Bebe passed closest to Funafuti at 2300h UTC (local time 1100h), 7-8 m waves affected the atoll, although major swamping of Fongafale did not occur until the tide started to climb and, in fact, after the wave heights had begun to diminish. The storm surge by itself was not enough to cause major flooding as the combined water level curve shows. While the major swamping on the rising tide occurred close to the time that the eye passed near to Funafuti, surge is not the only contribution. The contribution from waves is an important element, and the contribution of all components - surge, tide and waves - is critical. Calculations were made on the transformation of the offshore wave breaking across the wave-cut platform, together with tidal influence, to put the final inshore wave height impacting on the shore front at about 3.6 m. Summary diagrams show that, despite the presence of the maximum wave height for TC Bebe at Funafuti, the lower stage of the tide prevented overtopping at this point. Although the wave heights were smaller as the cyclone passed, the rising tide was enough to tip the balance at this point and overtopping of the banks and swamping of Fongafale occurred.
42
Working Group 1
(Lagi, Pasemeta, Yvette, Bailey, Matio, Tipelu, Falealili)
Which disasters have affected Fongafale?
1972 Tropical Cyclone Bebe in Funafuti: wave hit house, collapsed, runway flooded, people had to swim, over head-height, strong current flowing along runway out to sea in the north 1990 Cyclone Ofa mainly affected Vaitupu: houses collapsed, breadfruit and coconut trees were uprooted, inter-island boat nearly sank, waves over lagoon, island flooded. In Funafuti strong winds only 1997: 5-11th February: in Funafuti seawater above ground level, sea water intrusion from ground but also flooding from lagoon (see map) 1997 Cyclone Keli: part of main road on Fongafale washed away, trees and shrubs ripped out, small islet in passage disappeared
What were the main impacts of the disaster and the main problems of the community in recovering?
Worried about houses, some without shelter, sometimes stayed in houses until collapsed, usually people taken to safe houses: typically brick house built away from the beach, could be church or meeting hall (maneapa). Food (shops demolished) but then there was plenty of local food, and government brought food on Nivanga (boat), now food is a problem. Traditionally harvest germinating coconuts (utanu), and eat inside (like apple), when new shoot is big enough then it is right to eat. Husk utanu and bury ‘apples’ to preserve them under light cover of soil. Red Cross took people to shelter house, school classrooms; traditionally family relatives help if they have goods No fish because of rough seas Usually there is a lack of water after cyclone, especially if there was a drought before the cyclone Sanitation problem: during and after cyclone because of sharing
43 Up to 20 persons share 1 house with sanitation facility, flooding affects the earth pits Fruit damage (pandanus, bread fruit, banana, pawpaw, felo) Pulaka pits: saltwater kills root, roots need to be taken out and replanted 3-4 weeks later, when water becomes fresh again. Pulaka takes 6 years to mature, can’t store very long, there are traditional preservation techniques (can dry, or grate and dry it), but these are normally not practised after disaster because people are busy with other things and younger generation do not prefer to eat root crops Traditional storage is not carried out any more (eg. mash breadfruit to a flour), but if needed they can do it with warning of 6-12 hour, although nobody does it because usually the Government takes a hand. In general it is not considered practical to store for disaster because there is only a low expectation of a disaster return period of about 10 years. There is also no seasonal storage for the cyclone season
What measures have been taken since by the communities, by Government organizations and their projects/programs and by non-government organizations?
Community measure: After disaster and in general there is a strong sharing ethic, children and elders first Traditional houses make up a very small percentage of houses on Fongafale, and then generally only in the form of extensions. There is usually an attached kitchen - fale umu (cooking fire house). New houses are usually built according to draft building code There is usually a media announcement for the men to rope down their roof, particularly to the civil servants, because many houses (50-70%) belong to the Government. PWD does not have a system of routine checks of houses and if you do request a check it takes months and months to service or may never happen at all. Usually the house owners look after their roof, but usually only when a disaster approaches. Government: The National Disaster Committee. You can request PWD to cut down trees through PWD representatives. Government gives out post-disaster food assistance. Government is seeking funding to elaborate disaster management plan. Government and donors are developing proposals for disaster mitigation, such as for communication e.g. equipment and satellite phone as well as solar systems instead of diesel-electric energy supply.
Problems of recovery:
Lack of cash is a problem, especially to repair houses. After Cyclone Ofa, Government distributed money for recovery as well as materials for houses (from Fiji). There is a shortage of community spirit.
Working Group 2
(Tavala, Faatasi, Peneueta, Ampelosa)
Which disasters have affected Fongafale?
Cyclone Ofa affected Fongafale: • Local (umo) hatches collapsed • People attempt to cut down trees along (near) Ministers´ house • Coastal building (Southwest) • Banana crops were badly destroyed as well as breadfruit trees • Seaspray • Seawall (lagoon) with coastal erosion • Hospital (old one) exposed window, could withstand wind • Buildings along lagoon side were mostly affected • Food and fish supply affected • Uncomfortable living conditions • Impact on community programme
44 • Flights and shipping affected • Communication (Hurricane Bebe in 1972), MV Monroi communicated to Tarawa
Main problems
• Disaster response group is at risk during disaster (PWD, Police, Met Office, Red Cross) • Coordination and communication • Public awareness
Measurements taken since
• Focus on government properties like hospital, government building, housing by the government • Red Cross distributes blankets etc. • Met Office updates media on Tropical Cyclone situation • Disaster Office established (to improve disaster coordination)
Working Group 3
(Solomona, Asita, Poni, Melali, Tom)
Which disasters have affected Fongafale?
Disasters on Fongafale: hurricane, tropical cyclone, storm surge and droughts
What were the main impacts or consequences of the disaster?
• Mass destruction: infrastructure, deaths, shipwrecks, communication, food supply/security, power failure • Mental impact • Health issues
What were the main problems of the community in recovering from the disaster?
• Lack of counselling services
45 • Lack of financial resources • No response plan in place • No early warning systems • No disaster preparedness awareness programs • No reporting base for disaster issues
What measures have been taken since?
• Establishment of NDMO (has a task force for helping before, during and after disaster) • Build local windbreaks (high fence made of coconut leaves) • Radio programmes (advises on disaster preparedness) • Educational programmes on disaster preparedness in schools (primary and secondary) • Building codes (but costly for individuals) • Increase of water projects • Tango assistance: disaster awareness programme, project proposals, water cisterns/tanks • Accommodation assistance by Island community
Presentation of Disaster-Related Programs in Tuvalu
National Adaptation Programs of Action (NAPA) Focus: Address immediate/urgent needs of the civil society/stakeholders with respect to climate change adaptation How: Bottom-up approach Consultation of stakeholders Donor: Global Environment Facility (GEF), total 200k USD Duration: 18 month, ending June 2005 Issues: climate change, sea level rise, climate variability and extreme events (e.g. cyclones)
Tango-FSPI Project Project title: Disaster Preparedness Activities: 1. Facilitation workshop 2. Pilot community Fongafale: o Facilitator team Set up o Consultation (postponed, after National Summit) o Preliminary report 3. Outer island Consultation: o 3 or 4 Outer Islands have been chosen o Set up facilitator team o Consultation o Report 4. Project Implementation
46 ADRA Tuvalu Adventist Development and Relief Agency - a humanitarian Ministry of the SDA Church • Disaster preparedness and respond • Small projects, community projects • Donors: Canada, State (USA) Headquarter, Australia, New Zealand Network: Roles of key ADRA Offices is mainly to work together with local governments, NGOs and private organizations ADRA is an agency of the church • Which has its own body fund • Ministry to show God’s love • Helping people to become independent • Regardless of race and religion • Breaking prejudice and building bridge • An agent of change • Code of conduct ADRA is new in Tuvalu, they have a Memorandum of Understanding with Government, ADRA is about to plan their activities, not yet any projects
Mitigation Topics Identified in the three Working Groups
• Communication • Family preparedness (e.g. no food storage) • Public awareness • Housing / shelter • Water supply • Food (pulaka pits, trees etc.) • Sanitation • Building code • Response plan • Solar systems • Coastal erosion • Counselling services • Disaster response groups at risk The workshop participants considered the first seven topics on this list (bold) as the most important mitigation topics to work on during the next two days in order find solutions to mitigate the problems.
5. THURSDAY PROGRAM
Working Group “Communication”
(Petueli, Pasemeta, Solomona, Tavala, Peneueta, Leitoga)
What is the problem?
• Back-up system • Lack of funding • Un-trained operators
47 Why have the current mitigation activities not solved the problem?
• Funds to implement the above
PLAN OF ACTION: COMMUNICATION
Technical Sub-activities/ Who carries out Activities assistance/ Material, workforce, funds comments activity? funding Telecom-Satellite Telecom: Satellite Phone Phone Telecom TA, ROC, HF sets Back-up System TMC-AM (for TMC SOPAC, AusAID, TMC: Antenna mast, Transmitter back-up) MET NZ Aid, Tuvalu MET: Qfax, EMWIN MET-EMWIN TA, ROC, Staff of –Telecom, Training Training overseas SOPAC, AusAID, -TMC, MET NZAID, Tuvalu
Discussion in Plenary:
In the Met Office it takes 20 minutes to download 1 picture for disaster forecast, the internet speed is much too slow for disaster warning purposes (Server 164). The band-width should be increased, this might happen, when Government moves into the new building. ISP is the computer dept. for the server
Working Group “Family Preparedness”
(Tom, Siaosi, Asita, Falealili, Matio, Poni, Levi, Poopu)
What is the problem?
1. Financial problems: lack of money to finance building of houses and food supply, unwise use of money 2. People unaware of seriousness of natural disasters 3. Change in lifestyles: ignoring of local food 4. Delay in disaster warnings 5. Negligence of seriousness/damage of natural disasters
Why have the current mitigation activities not solved the problem?
1. People’s attitude is very discouraging 2. Wage and salaries are very low 48 3. High rate of unemployment 4. Awareness training: Participants (of training workshops) are depending on allowances 5. No high level’s support from decision-makers 6. Media is not serving for 24 hours 7. Communication equipment is insufficient
PLAN OF ACTION: FAMILY PREPAREDNESS
Who carries out Technical assistance/ Material, Activities Sub-activities/ comments activity? funding workforce, funds Island Communities, Island BINGO, Walk-a-thorn, Donors (local and Fund raising small organizations, Communities dances/twists, tax abroad) government (Voluntary) Train-the-trainers program Video Awareness Video presentation (in Tuvaluan) NCC, NDMO, Local SOPAC/Government presentation (in program Teach in schools (primary and Government Tuvaluan) secondary curriculum) Train subsistence farming to Women communities Households (matai o Revive people in each family Nutritionist Canada Local farming kaiga) subsistence Train people on local food Fund tools Schools (teachers farming preservation FAO Local expertise etc.) Raise taxes for imported food Nukufetau Island NZAID, AusAID, ROC, Improvement of Met Office forecast to speed up Met Officer SOPAC, Tuvalu Latest technology technology warning Government
Discussion in Plenary:
• Nowadays people buy imported food instead of preserving local food. • Imported tin food has an expiry date whereas the traditionally preserved crops (dried) last much longer. • Funafuti often runs short on imported food. • Without imported food Funafuti doesn’t have enough food, only the Outer Islands do produce enough food. Preserved food from the Outer Islands could be sold in Funafuti and is very tasty (however: the young generation prefers imported food). • The local government has a food project on poultry, piggery and gardening (donor not known). • People don’t take the risk of natural disasters seriously because nobody has died. But seven people died from Cyclone Bebe (which is not known by everybody).
Working Group “Water Supply”
(Tom, Bailey, Pasemeta, Levi, Tipelu, Poni)
49 What is the problem?
1. Gutters: 80 % of Funafuti’s population does not have gutters in the houses 2. Storage: Insufficient water storage capacities in Funafuti 3. Lack of water conservation 4. Overcrowded: e.g. big families with only 1 toilet 5. Limited funds 6. Well water being polluted: even people themselves do not make use of well water
Why have the current mitigation activities not solved the problem?
1. People do not buy gutters, spacing between brackets is very poor 2. Poor maintenance of water storage capacities, limited water storage capacities 3. No introduction of water conservation 4. High consumption of water 5. Lack of opportunity cost, poor prioritising for use of money 6. People prefer rain water to well water, poor quality of well water
PLAN OF ACTION: WATER SUPPLY
Sub-activities/ Who carries out Technical assist./ Material, Activities comments activity? funding workforce Encourage PWD and other responsible Identify a board to PWD, Kaupule, board PWD, Kaupule, board Gutter, brackets agencies to work assess buildings members, individuals members, individuals together Building of water Introduce building of Government, Public storage capacities Attorney General’s more water storage Health, Local Introduce water Office capacities government conservation Maintenance of existing Maintain structure of Kaupule, individuals, Government well water well water community people
Discussion in Plenary:
• With “Lack of opportunity costs” is meant that for example people do not save money for gutters but play BINGO instead. • The storage capacity of water should be increased with household and with public community tanks. • The desalination plant suffers blackouts due to frequent problems with the power plant (generator). • There are individual and community wells and sometimes conflicts between families on the use of the wells. • Public Health Dept. is testing wells of families and communities. The water quality is often bad. They visit the families and advise them to boil water. Sometime there is treatment from Public Health e.g. with chlorine. • The cholera was introduced to Tuvalu with the pit latrine program
50 Working Group “Housing”
(Petueli, Tavala, Falealili, Faatasi, Leituga, Matio, Solomona, Lagi, Asati, Poopu, Siaosi, Peneueta)
What is the problem?
1. Orientation of the house 2. Weak house foundation 3. Weather proof shelters 4. Building code 5. House structure 6. Materials 7. Risk of nearby trees 8. Funds
Why have the current mitigation activities not solved the problem?
1. Building code not implemented (government) 2. Lack of experience (of disasters) 3. Kaupule town plan not effective (spacing etc.) 4. Bye-laws not effective 5. Not enough funds
PLAN OF ACTION: HOUSING
Sub-activities/ Technical assist./ Activities Who? Material, workforce comments funding Public awareness on Media Government NDMO Building material improvement of Leaflets Interested donors PWD PWD housing Workshops overseas
51 Discussion in Plenary:
• The building code has existed for a long time but is not implemented yet. It is easy to regulate houses with imported material, but the problems are regulations for houses built with local materials in traditional styles. Just recently traditional houses have been included in the regulations of the building code and there is the hope, that the building code will now be implemented in October. • The implementation of the building code is mainly based on a training program for the town island councils? • PWD set up a sample house with building code standards on Vaitupu. • PWD has a housing program, but it is on hold due to lack of funds. • PWD only focuses on Government housing, not on houses of the communities. • Individuals have to submit the plan for a new house to the Kaupule • Nowadays the island communities do not have a system for regular community work. If there is a donor project, which benefits the community, labour input from the community is included as counterpart contribution. In that case the Kaupule organises the work with the community members.
6. FRIDAY PROGRAM
Working Group “Food Supply”
(Petueli, Tavala, Falealili, Faatasi, Leituga, Solomona, Peneueta)
What are the problems?
1. Poor soil 2. Limited land on Funafuti 3. Change in diet from local to imported food 4. Limited knowledge in preserving local food 5. Cost of imported food 6. Food storage (overpopulated eg. on Funafuti) 7. Low income
Why have the current mitigation activities not solved the problem?
1. Unfertile soils 2. No town planning 3. Imported food is more convenient 4. Lack of training in preserving local food 5. Lack of price control 6. Not enough stock 7. Overpopulation with increasing social functions (weddings, funerals, cocktails, etc.)
PLAN OF ACTION: FOOD SUPPLY
Who carries out Technical assist./ Material, Activities Sub-activities/ comments activity? funding workforce Agriculture Dept., Waste Management (increase Improve soil with Waste Management FAO compost) Fertile soil gardening Office, Government, ROC Import soil (e.g. from Fiji) Kaupule PWD, Government, SOPAC, ROC, Gravels, sands, Land reclamation Filling of pits and ponds Kaupule AusAID, NZAID plants Media, Health, FAO, SOPAC, SPC, Leaflets, Public awareness Media, Health, Agriculture, Agriculture, Kaupule UNFPA, media, travel programmes Kaupule (Outer Islands) (Outer Islands) Government, WHO expenses
52 Discussion in Plenary:
• Compost is sold at the waste dump site • At social functions people waste a lot of food. It is a tradition to offer abundance of food. The Womens Dept. is raising awareness on waste of food and usage of food in a more economical way. • In former times there were agricultural activities on the other islets, nowadays people consider it as too much work and too difficult because of fuel costs. The land belongs only to Funafuti people, the land only belongs to Funafuti community, and the other communities can’t use the land.
Working Group “Public Awareness”
(Tom, Asita, Siaosi, Matio, Peneueta, Levi, Poni, Lagi)
What are the problems?
1. Attendees are attracted by allowances 2. Poor information dissemination 3. Few local personnel to deliver public awareness programs 4. Media not serving for 24 hours 5. Local peoples´ ignorance of prevention measures 6. Very little faith (Far from God!) 7. Expensive
Why have the current mitigation activities not solved the problem?
1. Change in lifestyles (people heavily depending on money 2. Effective communication link 3. Brain drain: Qualified Tuvaluans attracted overseas 4. Limited funds 5. Traditional peoples´ nature: Prevention does not matter to Tuvaluans, different seriousness of disaster (typhoon, cyclone etc.) does not matter to locals 6. Most people are worshipping money 7. No money!!!
PLAN OF ACTION: PUBLIC AWARENESS
Who carries out Technical assist./ Material, Activities Sub-activities/ comments activity? funding workforce Media Workshops Health WHO, SOPAC, SPC, Leaflets, Subs, Public awareness Leaflets NDC UNFPA, Government travel expenses TV Town Planning, Building Code, Public Government, Kaupule, leaflets, tents, Government, ROC training Health Act Health training Youth, Women’s Kaupule Community plan training community, Media Government
Discussion in Plenary:
• Recently a tidal wave alert was announced in the morning to hit at 11am. The police went around and warned everybody, but the people just laughed and continued with their daily business instead of going home to prepare themselves. “Time is money nowadays”. • In Tuvalu language there is only one word for all different sorts of disasters, which means “strong winds”, so people don’t differentiate the potential risks. • In former times every family had devotion time at 6 or 7 pm. • Radio transmission time: 1½ hours in the morning, 1½ in the afternoon, 4 in the evening. During cyclones 24 hours, paid by the Government. Transmission time for awareness talks are expensive (estimation: 100 AUD for ½ hour)
53 • As a decentralization policy, the Government tries to raise the attractiveness of the outer islands by providing electricity etc.
Working Group “Sanitation”
(Petueli, Tavala, Falealili, Faatasi, Leituga, Solomona, Peneueta)
What is the problem? What causes it?
1. Commmunicable Diseases Poor facilities 2. Overcrowded (Individual household) Size of houses and facilities 3. Contaminated water Disaster debris 4. Waste Solid and liquid waste (animals, chemicals etc.) 5. Increased number of vectors Pesticides, vermins, insecticides, rodencides 6. Food quality Stress and panic during disaster, Money
PLAN OF ACTION: SANITATION
Who carries out Technical assist./ Activities Sub-activities/ comments activity? funding Island communities, Provide funds during Public Island Communities to run own PAPs Interested donors and Leaders, NGO, officials, Awareness Programs (PAPs) Provide allowance to participants government, SPREP TANGO NDMO and relevant Prepare a plan Prepare information for plan Government agencies Review program Redundancy program Government, media, Government, donors, Train more locals Increase various attractive programs to officials SPREP attract more money Priests, Pastors, Conduct more public religious Religious programs for Youth and Priest, Elders, Ministers Elder, Government, programs children donors
Working Group “Waste Management”
(Tom, Asita, Siaosi, Matio, Peneueta, Levi, Poni, Lagi)
What is the problem?
1. Countless Rubbish / Wastes o Waste cars o Tins, cans, … o Nappies, clothes, … o Etc… 2. Low public awareness o Not knowing to sort rubbish 3. Rubbish/ Waster clearance service – very poor!!!
Why have the current mitigation activities not solved the problem?
1. Very high imported second hand goods. Policy is not strong enough to discourage such goods 2. People are not ready to face the consequences of today 3. Lack of equipment and workforce / expertise
54
PLAN OF ACTION: WASTE MANAGEMENT
Technical assist./ Activities Sub-activities/ comments Who carries out activity? funding Produce “strict” policy to Workshops for the public to aware on stop import of 2nd-hand everybody Government this goods Training of the trainers Government, donors, WMO, Government, Trainings required Trainings and workshops Waste Management Office donors Provide quality equipment Provide quality employed people Government, donors, Government, donors, Acquire more equipment Include in schools curriculum everybody small organizations (strengthen)
Discussion in Plenary:
• Liquid and chemical waste has to be included • Discussion on the question if cholera was caused by liquid waste • There is the problem between Kaupule and Waste Management Office (WMO) after AusAID dropped out. Now they both run the waster Management and the collection. Kaupule pays for fuel and for salaries and owns the truck? WMO owns ? • “Truck distributes rubbish rather than collects it” • Each family pays AUD$30 per year. If Kaupule did management on its own, the fees would rise. • Waste management has to be included in school curriculum
7. CLOSING
We thank Sumeo Silu for his effective organization and coordination of the workshop and the facilitators Petueli Noa and Tom Hauma for supporting the workshop and the various working groups. Ultimately, it was the participants who made the workshop a success by spending three days of their time with constant discussion for the benefit of the communities of Funafuti. They gave us an understanding of the vulnerability of Funafuti and its problems and brought the project forward towards finding solutions for disaster mitigation.
Dr. Graham Shorten, Dr. Susanne Schmall, Fellow Participants – Ladies and Gentleman. It is an honour and privilege for me as Disaster Coordinator to be given this opportunity to present the closing address of this important Community Workshop. Some of you may recall the Prime Minister’s opening remarks two days ago, he indeed asked the participants to focus on the Tasks at hand and ensure that the outcomes of the workshop will truly assist in reducing the risk to the community. The sub-projects that have developed from this workshop will clearly identify practical solutions to the problems posed by Disasters in our Community. I am glad that this project has now focussed and addressed our vulnerability within our community. I am sure that the inputs you have contributed to the workshop will be immensely for the betterment of the most vulnerable community on Fongafale. We all hope that committed donors will able to reach deeper into financing these sub-projects. At this juncture, I would like to utilise this opportunity, on behalf of the Government of Tuvalu, to express our gratitude and appreciation particularly the Government of the Republic of China for their kind assistance in providing funds to support this project. My special thanks also go to Dr. Graham Shorten and Dr. Susanne Schmall who have willingly and readily made themselves available to fulfil the SOPAC obligation on this project. I also thank the local facilitators for the untiring effort taken to make this workshop a success. Ladies and gentlemen! Without any further ado, I now have the pleasure of declaring this Community and Vulnerability Workshop closed. Fakafetai Lasi.
55 List of Participants
Lagi Etoma Community Leader Nukulaelae Peneueta George Community Leader Nukufetau Poopu Asueli Community Leader Vaitupu Siaosi Finiki Community Leader Funafuti (Ulufena Funafuti) Solomona Lelemia Funafuti Town Council (Kaupule), President Falealili Feagai Public Health, Sanitation Inspector Bailey Koulapi ADRA Tuvalu Asita Molati Women Dept. Matio Lonalona Dept. of Agriculture Ampelosa Tenulu Deputy Director of Works (PWD) Levi Telii Representative PWD Tauala Katea Acting Director, Meteorological Service Faatasi Malologa Lands and Survey Dept. Pasemeta Talaapa EU-NZAID In-Country Coordinator Poni Faavae NAPA, Dept.of Environment Yvette Isaac Tuvalu Media Corporation (TMC) Melali Isaia General Manager, Tuvalu Media Corporation (TMC) Tipelu Kauani Deputy Commissioner of Police Leitonga Tauaa Dept. of Home Affairs
Opening: Hon. Saufatu Sopoanga Prime Minister of Tuvalu Rev. Kautoa Moloti EKT Representative Dr Feng Tai Ambassador of the Republic of China to Tuvalu Robin Cheng Embassy of the Republic of China Uale Taleni Senior Assistance Secretary, Office of the Prime Minister Hellani Tumua Administrative Officer, AusAID Office
56 Annex 2
Cyclone Hazard Assessment,
Funafuti Preliminary Project Findings
Graham Shorten, Stephen Oliver, Matt Eliot
Disaster Vulnerability and Mitigation Workshop Vaiaku Lagi Hotel, Funafuti
23 –25 June, 2004
57 Cyclone Hazard Assessment, Funafuti Preliminary Project Findings Graham Shorten, Stephen Oliver, Matt Eliot
Disaster Vulnerability and Mitigation Workshop Vaiaku Lagi Hotel, Funafuti 23rd-25th June, 2004
Questions after Disaster Outline of Presentation
• Was anybody hurt? • Cyclone Banks on Fongafale • Who’s going to clean up the mess? • Focus on TC Bebe, 1972 • Effect of Storm Surge • How much will the repairs cost me? • Interaction with Tides • How much will insurance cover? • Offshore Wave Height • How can I do it better next time? • Impact of Waves Onshore • What design changes are needed? • Future Directions vs – Digital Terrain Models Risk Management Disaster Response – Hydrodynamic Modelling – Early Warning System
1 Bebe1
4.00 3.50 3.00 2.50 2.00 1.50 1.00 0.50 0.00 RL relative to (m) WCP 50 45 40 35 30 25 20 15 10 5 0 -5 Distance from Junction of WCP-Swash Zone (m)
Swash-Zone Beach Bebe2
Recent Storm Berm 4.00 3.50 3.00 TC Bebe Storm Berm 2.50 2.00 Lagoon-Side Sediments 1.50 1.00 0.50 Old Storm Berms 0.00 RL relative to WCP (m) WCP to relative RL 50 45 40 35 30 25 20 15 10 5 0 -5 Limestone Distance from Junction of WCP-Swash Zone (m) (Cemented Storm Berm) Bebe3
4.00 3.50 3.00 2.50 2.00 1.50 1.00 0.50 0.00 RL relative to WCP (m) to WCP relative RL 50 45 40 35 30 25 20 15 10 5 0 -5 Distance from Junction of WCP-Swash Zone (m)
Bebe4
4.00 3.50 3.00 2.50 2.00 1.50 1.00 0.50
0.00 (m) WCP to relative RL 50 45 40 35 30 25 20 15 10 5 0 -5 Distance from Junction of WCP-Swash Zone (m)
2 320 1000
300 Peak Gust 990 280 Cent ral Pressure 980 260 970 240 220 960 200 950 180 940 160 930 140 Central Pressure (hPa)
Peak Gust Speed (km/h) Speed Gust Peak 920 120 100 910 80 900 12345 Cyclone Category
Low pressure causes elevation of sea level due to “inverse barometer effect”
Wind forcing surge over the shallower lagoon
3 Surge max occurs closer to low tide
First Conclusion 2303::00h Octt.. 21, 1972: Cyclone over Funafuti – “swamping occurred” The net storm surge does not seem to have been too high
The next question
What about the impact of waves ?
“the storm tide by itself is not enough “swamping” occurs to cause major some time here 5 flooding 5 5 5 5 Tides 4 Tides 4 Tides 4 TidesCrest So this not when 4 Surge Crest 4 Tides ) 3 SurgeSurge ) 3 wavesSurge are highest ) 3) 3 WaterWater Level Level (Surge+ (Surge+ Tide) Tide) Water Level (Surge+ Tide) 2 2 2 2 1 1 1 1 Height (m-MSL Height Height (m-MSL Height Height (m-MSL Height
Height (m-MSL Height 00 Height (m-MSL) Height 0 0 0 -1 -1 -1 -1 -1 -2 -2 -2 But when tide-storm -2 -2 Initial Approx Initial Approx surge and waves all
19-1200 20-0000 20-1200 21-0000 Flooding21-1200 eye Initial Approx Initial Approx Initialdescribed FloodingApprox eye 19-1200 20-0000 20-1200 21-0000 21-1200 Flooding eye Flooding eye 19-1200 20-0000 20-1200 21-0000 21-1200 19-1200 20-0000 20-1200 Time (UTC)21-0000 Flooding 21-1200 eye combine – the wave
19-1200 described described Time (UTC)describeddescribed TimeTime (UTC) (UTC) Timedirection (UTC) is also important
4 9 9 10 2.0
9 1.6 8 8 8 1.2 7 7 Wave Period 7 0.8 6 6 6 0.4 5 5 5 0.0 4 4 4 -0.4 Wave Period (s) 3 3 3 -0.8
Wave Height Significant Wave Height (m) Relative Tidal Level (m MSL) (m Level Tidal Relative Significant Wave Height (m) 2 2 2 -1.2
1 1 1 -1.6
0 0 0 -2.0 19/10/72 19/10/72 20/10/72 20/10/72 21/10/72 21/10/72 22/10/72 19/10/72 19/10/72 20/10/72 20/10/72 21/10/72 21/10/72 22/10/72 0:00 12:00 0:00 12:00 0:00 12:00 0:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00
10 2.5 Breaking waves coming from the south-east
9 2.0 Wave run-up
8 1.5 8 depends on water level & Water Level Waves break 7 1.0 6 wave heights over shallows 6 0.5 4 Inshore
5 0.0 2 and Wave Crest Height
0 4 -0.5
-2 HeightMSL) (m - Offshore Offshore 3 -1.0 Water Level MSL) (m -4
Significant Wave Height(m) Wave Height 2 -1.5 -6 1 -2.0 -8 0 -2.5 19/10/72 19/10/72 20/10/72 20/10/72 21/10/72 21/10/72 22/10/72 0:00 12:00 0:00 12:00 0:00 12:00 0:00
The waves are not as large here but the sea level has risen due to tide and storm surge
8 Now the run-up What happens if some overtops and 6 starts flooding the things change ? 4 island
2
0 • The cyclone comes later or earlier
-2 HeightMSL) (m - • The cyclone takes a different path -4
-6 • The cyclone is stronger or weaker
-8
5 Airborne Laser Scanning - a GPS satellites The concept of Airborne Laser Broad-acre Mapping Technique Scanning - summary • Advanced satellite positioning system (GPS) and navigation systems Scan angle of the onboard the aircraft. scanner • Differential post-processing s Direction of e of GPS measurements tr the flight e • m Flying height of 500 to 3000 0 0 metres 1 2 o t p One GPS u th id Ground station w
n a c S
General Presentation
Water Management Modelling Beach Erosion
• flood analysis • erosion control and monitoring
Extract: Burdekin River vegetation removed
Future Directions
• Tuvalu requires funding for:
– Digital Terrain Models – Hydrodynamic Modelling – Early Warning System – Risk-GIS Database – Community Projects
6
Annex 3
RESTRICTED CIRCULATION
SOPAC/Taiwan-ROC
Building Capacity to Insure Against Disasters in Tuvalu
Proposals for Risk Treatment Projects
LOGICAL FRAMEWORK DESCRIPTIONS
By
Dr Susanne Schmall & Dr Graham Shorten
64 Annex 4
Photo Documentation to Complement the Project Summary of Mitigation Issues for Tuvalu
65
Photo 1: Erosion and degradation of seawalls and jetties is common on the lagoon side of Fongafale
Photo 2: Tuvalu’s communication systems may not have adequate redundancy during disasters
66
Photo 3: Many household rain-water catchments, delivery and storage systems are inadequate to cope with drought or cyclone disasters
Photo 4: Old car and truck bodies litter the island of Fongafale with no prospect of removal
67
Photo 5: An AusAID solid waste disposal project has begun to address the problem on Fongafale
Photo 6: Many compounds now have one or two bins that allow for some sorting of solid waste
68
Photo 7: Liquid waste poses a problem to Fongafale and its groundwater as well as the solid waste issues
Photo 8: Some of the more low-lying areas of Fongafale even become flooded by rising groundwater during king tides
69 Annex 5
RESTRICTED CIRCULATION
Cyclone Hazard & Proposals for Risk Treatment, Funafuti
SOPAC/Taiwan-ROC
Sumeo Silu, Susanne Schmall & Graham Shorten
Tuvalu National Summit for Sustainable Development, Funafuti
July, 2004
70 Annex 6
TUVALU WAVE RISK STUDY
Prepare For
South Pacific Applied Geoscience Commission
GEMS Report 29/04 June 2005
Funding: Taiwan-ROC
71 GEMS – Global Environmental Modelling Systems Report 29/04
Document Status
Rev Approved for Issue Author Reviewer No. Name Signature Date
1 Stephen Graham Stephen SEO 17/6/05 Oliver Shorten Oliver
2
This document is and shall remain the property of Global Environmental Modelling Systems Pty Ltd. The document may only be used for the purposes for which it was commissioned and in accordance with the Terms of Engagement for the commission. Unauthorised use of this document in any form whatsoever is prohibited.
This document and the work undertaken for its preparation are presented for the use of the client. Global Environmental Modelling Systems (GEMS) warrants that the study was carried out in accordance with accepted practice and available data but that no other warranty is made as to the accuracy of the data or results contained in the report.
GEMS notes that the report may not contain sufficient or appropriate information to meet the purpose of other potential users. GEMS therefore, does not accept any responsibility for the use of the information in the report by other parties.
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Table of Contents
1 INTRODUCTION ...... 6 1.1 OVERVIEW...... 6 2 CYCLONE IMPACTS...... 7 2.1 CYCLONE CLIMATOLOGY ...... 7 2.1.1 Storm Data Base...... 7 2.1.2 Inter-annual Variability of Storm Occurrence ...... 7 2.1.3 Theoretical estimates of cyclone intensity ...... 10 2.1.4 Long Term Intensity Estimates ...... 11 2.2 GENERAL CYCLONE EFFECTS ON SEA LEVEL...... 12 3 FONGAFALE MORPHOLOGY ...... 15 3.1 PROFILES AND DEPOSITIONAL CHARACTER ...... 19 4 NUMERICAL MODELLING...... 20 4.1 OVERVIEW...... 20 4.2 MODEL DESCRIPTIONS ...... 20 4.2.1 Cyclone Winds ...... 20 4.2.2 Storm Surge Model ...... 20 4.2.3 Wave Model (SWAN) ...... 21 4.2.4 Wave Run-Up & Overtopping...... 25 4.3 MODEL VALIDATION – CYCLONE BEBE...... 35 4.3.1 Storm Track ...... 35 4.3.2 Model Results...... 35 4.3.3 Quantification of Flooding: Implied Food Levels ...... 44 5 WAVE RISK ANALYSIS...... 45 5.1 OVERVIEW...... 45 5.2 STORM VARIABLES ...... 45 5.3 SUMMARY OF RESULTS...... 47 5.4 EVENT PROBABILITY...... 52 5.4.1 Climate Change ...... 53 6 SUMMARY & CONCLUSIONS ...... 54 6.1 RISK AT FUNAFUTI ...... 54 7 REFERENCES ...... 56 8 APPENDIX 1: OVERTOPPING TABLES...... 59
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List of Figures
Figure 1. Cyclone locations and intensity in the Tuvalu region 1969-2004...... 8 Figure 2. Cyclones in the Tuvalu region 1972 – 2004...... 9 Figure 3. Tuvalu region cyclones versus monthly Southern Oscillation Index (SOI). Storm intensity in indicated by the length of black bars...... 10 Figure 4. Observed (blue) and fitted probability distribution (red) for central pressure for storms in the Tuvalu region...... 11 Figure 5. Processes contributing to sea level at a coastal location...... 13 Figure 6. Track of Cyclone Bebe...... 14 Figure 7. Outline of Fongafale and location of cross-sections...... 16 Figure 8. Cross-sections by Japanese survey team...... 16 Figure 9. High resolution storm surge model grid...... 23 Figure 10. Modelled storm surge (green line) associated with Cyclone Bebe...... 23 Figure 11. Extent of SWAN grids...... 24 Figure 12. SWAN model outpoints...... 25 Figure 13. Schematic for Wave Overtopping Model ...... 26 Figure 14. Effect of Freeboard on Wave Transmission ...... 28 Figure 15. Combined Effects of Platform Width and Wave Period on Wave Transmission ...... 29 Figure 16. Typical storm event response for a steep profile...... 29 Figure 17. Typical storm event response for a flat profile...... 30 Figure 18. Stable grade for 200-mm rubble as a function of wave height and period 31 Figure 19. Stable grade for varied rubble sizes, wave period 8 seconds ...... 32 Figure 20. Profile flattening for a broad crest...... 33 Figure 21. Profile flattening and crest deflation for a narrow crest...... 34 Figure 22. Track of Bebe and extent of stronger winds as the storm passes Funafuti...... 36 Figure 23. Evolution of broad scale wave field with approach of Cyclone Bebe towards Funafuti...... 37 Figure 24. Combined sea level and wave crest height, corrected for normal component to shore line at Locations 1, 2 (ocean side) 3 and 4 (lagoon side). 39 Figure 25. Computed evolution of overtopping at Locations 1, 2 (ocean side) 3 and 4 (lagoon side) during Cyclone Bebe...... 39 Figure 26. Comparison of significant wave height with wind speed...... 40 Figure 27. Relative sea level heights: Tide, Storm Surge, Wave Crest...... 40 Figure 28. Comparison of wave crest height, corrected and uncorrected for normal component to shore line (southeast Funafuti)...... 41 Figure 29. Comparison of combined sea level and wave crest height, corrected and uncorrected for normal component to shore line (southeast Funafuti)...... 41 Figure 30. Modelled wave conditions through TC Bebe (Oct 1972) ...... 42 Figure 31. Modelled Wave Transformation...... 42 Figure 32. Locations for computation of overtopping rates...... 43 Figure 33. Modelled Overtopping Discharge During TC Bebe...... 43 Figure 34. Average cross section for southeast arm of Funafuti atoll...... 44 Figure 35. Cyclone tracks...... 46 Figure 36. Key Diagram to Overtopping Matrix (see next page)...... 50 Figure 37. Relative frequency of tide heights at Funafuti...... 52
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List of Tables
Table 1. Cyclones in the Tuvalu Region 1969-2004...... 8 Table 2. SWAN Grid Specifications...... 24 Table 3. SWAN Model Settings...... 24 Table 4. Expected mean grade...... 32 Table 5. Summary of stability relationships...... 33 Table 6. Estimated flood levels, above ground level as a function of inundation rate. 44 Table 7. Summary of cyclone specifications...... 45 Table 8. Estimated maximum significant wave heights for the design cyclone tracks (ocean first, and lagoon)...... 48 Table 9. Estimated storm surge heights for the design cyclone tracks (ocean and lagoon)...... 49 Table 10. Matrix of Cyclone Central Pressures versus Approach Tracks showing Overtopping Potential at Funafuti, Tuvalu (tide level: 1.0 m above MSL)..51 Table 11. Average recurrence Interval (years) for a range of over-topping rates for mean sea level based on current climate, and IPCC mean predictions for 2050 and 2100...... 53
List of Plates
Plate 1. Coral rubble overlying cemented platform...... 17 Plate 2. Shingle accumulation on southeastern shore...... 17 Plate 3. Low-lying land west of shingle ridge...... 18 Plate 4. Airstrip...... 18
Acknowledgments
GEMS gratefully acknowledges the significant contribution by Mr Matthew Eliot on wave run-up modelling, and the contribution by Dr Graham Shorten on geological and topographic profiles of Fongafale. The permission of the Government of Tuvalu and the Director of SOPAC to publish the information in this report, and the funding support for the project from Taiwan-Republic of China, are also kindly acknowledged.
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1 INTRODUCTION
1.1 Overview
Global Environmental Modelling Systems (GEMS) has been commissioned by SOPAC to undertake a wave risk study for Tuvalu, focusing in detail, on the island of Funafuti.
The requirement for such a study is underlined by considering the impact of Tropical Cyclone Bebe in October 1972. Cyclone Bebe, a Category 3 storm, passed just to the east of Funafuti and caused extensive flooding over the main cay. It also had a considerable physical impact on the island of Fongafale as it established a new rampart on the eastern side of Funafuti atoll.
When considering the impact of Bebe, a number of questions arise as to the long-term risk of such impacts in the Tuvalu group. These include:
• are more intense storms possible;
• what happens if the storm approaches on a different track;
• does the coincidence of the tidal cycle and the storm passage effect the degree of impact and if so, what are the worst case combinations;
• what are the most important physical processes during severe events;
• how would climate-change scenarios impact on risk;
• can the real-time the emergency response procedures be adjusted based on predicted oceanic response for a predicted storm track and intensity, and
• can mechanisms be developed to mitigate potential impacts?
An important aim of this study has been to provide quantitative information that will help to address these important strategic questions. Equally, the aim has been to provide information which can be used to assist in determining the level of threat during particular real-time events.
Since, the amount of relevant observational data is very limited, the approach adopted has been to use available data bases in conjunction with numerical modelling techniques to simulate longer term storm impacts in the region.
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2 CYCLONE IMPACTS
2.1 Cyclone Climatology
2.1.1 Storm Data Base
To determine the level of risk presented by tropical cyclones, it is necessary to construct a representative storm climatology. A database of tropical cyclones in the South-West Pacific developed by the New Zealand Meteorological Service (NZMS) formed the basis the analysis of cyclones carried out for this study.
Figure 1 shows six-hourly fixes defining the tracks of all storms in the general region around and to the south of Tuvalu during the period 1969 to 2004. The locations are colour-coded as a function of storm intensity as measured by central pressure. Table 1 details the names and minimum central pressures of those events. It is clear from this diagram that storm activity is less frequent over lower latitudes; over the 35-year period covered by the database, only 7 storms have formed north of the latitude of Funafuti (8.5° South) and only a few of these have crossed this latitude with a central pressure below 990 hPa. Just one storm, Bebe, had a pressure below 970 hPa at this latitude (945hPa), and this storm happened to pass almost directly over the atoll. Figure 2 shows the division between weak and strong storms in the region.
An obvious conclusion to be drawn from the preceding summary is that, notwithstanding the occurrence of Cyclone Bebe, the probability of any intense storm directly affecting Funafuti is relatively low. While this is true, the low frequency of storm occurrence in the region also makes it more difficult to estimate the probability and extent of extreme impact events.
2.1.2 Inter-annual Variability of Storm Occurrence
One way of assessing the degree to which the relatively short period of cyclone data represents longer-term trends is to consider related, but longer-period, data sets. The inter- annual variability of cyclone frequency in the South-West Pacific is known to be related to the variation of the so-called Southern Oscillation Index (SOI), which is based on the difference in mean surface pressure between Darwin and Tahiti. During El Niño events, the SOI exhibits a distinct negative bias and there is an accompanying eastward-shift in the area of South-West Pacific cyclone genesis.
This shift results in increased numbers of cyclones developing in longitudes around the dateline. The process is illustrated in Figure 3 which shows the incidence of Tuvalu cyclones
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plotted over a time series of monthly SOI values. Figure 3 shows that storm activity around Tuvalu is suppressed during La Niña (positive SOI) events and increases otherwise.
Table 1. Cyclones in the Tuvalu Region 1969-2004. Cyclone ID Month Season Minimum Pressure Anne January 1986-87 995 Bebe October 1972-73 940 Bob February 1977-78 997 Cliff February 1980-81 997 Cyc December 1984-85 989 Gavin March 1996-97 997 Gordon January 1978-79 997 Heta January 2003-04 980 Joni December 1992-93 997 Keli June 1996-97 990 Kina November 1982-83 997 Ofa January 1990-91 980 Raja December 1986-87 997 Steve November 1977-78 990 Tomas March 1993-94 999 Val December 1991-92 995
Figure 1. Cyclone locations and intensity in the Tuvalu region 1969-2004.
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Part (i): “Weaker storms”
Part (ii): “Stronger storms”
Figure 2. Cyclones in the Tuvalu region 1972 – 2004.
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80 Bebe 60
40 Ofa 20
0
Southern Oscillation Index -20
-40 Jan-69 Jan-71 Jan-73 Jan-75 Jan-77 Jan-79 Jan-81 Jan-83 Jan-85 Jan-87 Jan-89 Jan-91 Jan-93 Jan-95 Jan-97 Jan-99 Jan-01 Jan-03
Figure 3. Tuvalu region cyclones versus monthly Southern Oscillation Index (SOI). Storm intensity in indicated by the length of black bars.
While the cyclone database for Tuvalu does not date back beyond the late sixties, the SOI series extends back to the end of the 19th Century. This time series indicates that the rise and fall of the SOI is not significantly different than for the period of the database, indicating that storm frequency based on the database should be generally representative of a longer period.
2.1.3 Theoretical estimates of cyclone intensity
A further way to constrain the problem of setting storm intensities is to include theoretical considerations of cyclone genesis. Several attempts have been made to estimate the maximum storm intensity for a region based on thermodynamic considerations [9], [14] and [30]. These suggest central pressures below 900hPa for the low latitude South-West Pacific but do not consider limits on the forcing required to generate such low pressures. For example, it is accepted that tropical cyclones cannot deepen to their thermodynamic potential at lower latitudes (say within 10° of the equator) due to low levels of earth vorticity (Coriolis).
Holland [15] suggests that storms may occasionally deepen more substantially at such lower latitudes due to the presence of unusually marked local vorticity. He also suggests that this may imply that more intense storms be smaller in scale. These issues need further research and a modelling study for the region would have the capacity to add significantly to the knowledge base.
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2.1.4 Long Term Intensity Estimates
“Current Climate”
There is insufficient storm data to undertake a very reliable extreme value analysis of cyclone intensity for Funafuti storms. However, noting the limitations, such an analysis was carried out for the Tuvalu component of the South Pacific Sea Level Project [13]. Based on the available data for the Tuvalu region, Figure 4 shows the estimated probability density function for central storm pressure; this indicates a lower limit of about 925 hPa.
9 8 Observed 7 Predicted 6 5 4 3
Relative Frequency 2 1 0 995 990 985 980 975 970 965 960 955 950 945 940 935 930 925 Pressure (hPa)
Figure 4. Observed (blue) and fitted probability distribution (red) for central pressure for storms in the Tuvalu region.
Based on a regional storm frequency of 0.61 storms per annum, a cyclone of the intensity of Cyclone Bebe (945hPa) is expected to occur in the region approximately once every 70 years, while the probability of a direct impact on Funafuti is commensurately lower.
It must be stressed that there is considerable uncertainty in these estimates. The implied lower limit (925 hPa) is substantially above the thermodynamically estimated limit and although this is in accordance with the limitations of storm intensification outlined above, it is based on a small number of storms.
Climate Change Scenarios
There has been no regional specific study of the potential impacts of climate change on storm frequency or intensity. As a result, no connections can be drawn between climate change
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effects and altered cyclone impacts, or the downstream effects of this on wave and storm surge aspects of the current study. However, we note that changes to mean sea level will affect both mean storm surge levels and wave run-up and overtopping processes.
2.2 General Cyclone Effects on Sea Level
In determining the oceanic response to tropical cyclones, there are several processes to be considered:
(i) the rise and fall of the sea surface due to astronomical tides;
(ii) the storm surge, which includes the increase in sea level in the vicinity of the cyclone due to the so-called inverse barometer effect, and wind stress on the ocean surface;
(iii) wave set-up which relates to the mean increase in sea level due to the effect of breaking waves, and
(iv) wave run-up and overtopping along a shoreline.
These processes are shown schematically in Figure 5. Of the processes listed above, only the tidal and inverse barometer effects are important in deep water, whereas the other processes are dependent to varying degrees on ocean depth and the topography of specific shorelines. Storm surge impacts are generally greatest where a cyclone effects a coastline with a relatively large, shallow offshore region – examples are the Bay of Bengal, the Gulf of Mexico and Australia’s North West Shelf.
Since the Pacific Islands are generally characterized by rapid increase in water depth off their coastlines, the wind stress component of the surge is relatively small and the storm surge is dominated by the inverse barometer effect. Increase in the water level due to a cyclone is therefore generally restricted to regions areas close to the storm centre.
While the greater near-shore water depths restrict storm surge levels, they allow relatively greater impacts of oceanic waves – particularly in the absence of fringing reefs which allow greater dissipation of wave energy through breaking. For this reason, inundation of Pacific Island coastlines is much more likely to be due to the effect of large breaking waves.
Although the contribution of tide and storm surge may not be large in absolute terms, in many cases their contribution to the process of inundation is still likely to very important. The degree of wave impact is often critically dependent on the combination of the sea level; the
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particular wave characteristics; and both the offshore and onshore topography. Small changes in any of these conditions may lead to an increase of the wave response over a critical inundation threshold.
Wind Waves Wave setup
Storm Surge
Highest Tide Mean Sea Level Lowest Tide
Figure 5. Processes contributing to sea level at a coastal location.
Cyclone Bebe
Cyclone Bebe developed to the northeast of Funafuti during 20 October 1972 and began moving in a southeasterly direction, towards the atoll. The cyclone track is shown in Figure 6. The impact of the storm on Funafuti is well documented by Baines et al [2]. They describe the formation of an extensive, permanent rubble rampart on the eastern side of the atoll, and report on interviews carried out with residents. The main elements of the report with regard to the storm itself are as follows:
• The wind speed at Funafuti began to increase significantly during the afternoon of 21 October and into the evening, eventually exceeding 50 m/s, while the wind direction shifted from southeast through to southwest;
• The lowest barometric pressure of 954 (hPa) was recorded at the Funafuti Meteorological station at 2200 hours (21 October);
• Sea level began to rise during the early afternoon of 21 October and eventually flooded the airstrip to depths of 1.5 m (the timing of this maximum flooding is not given);
• Baines et al [2] report that flooding coincided with a high tide around 1530 hours, that afternoon;
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• There was a temporary decrease in the wind speed with the passage of the cyclone eye and then winds began to increase again from the southwest before gradually shifting to the west;
Figure 6. Track of Cyclone Bebe.
Residents reported that at 2215 hours, a single large wave with perhaps smaller following waves swamped the eastern half of Funafuti Island, destroying buildings and killing several people.
Modelling the general oceanographic and coastal processes that were described in the previous section, together with the extent and timing of the events described in the report of Baines et al [2], has been the subject of a significant component of the current study. These processes have been modelled with a view to understanding both the particular events associated with Bebe as well the long-term risk presented to Funafuti by other extreme cyclone events. The results of this modelling are described in the following sections of this report.
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3 FONGAFALE MORPHOLOGY
Fongafale is a long, narrow, low relief motu on the eastern side of Funafuti atoll, roughly L- shaped, with arms facing east-northeast and southeast (Figure 7). The eastern side of the island is comprised of a relatively narrow ridge comprised of coral rubble up to 5 m elevation, overlying a cemented limestone platform slightly below mean sea level (Plates 1 and 2). This platform acts to break much of the incident wave action, enabling accumulation of coral rubble and sand for the emergent atoll. Sand accumulation is present on the western, leeward side of the island, forming flat land roughly 1.0 m above mean sea level, which has its broadest extent around the central part of the island (Plate 3). Prior to recent development, a narrow depression, or gutter, ran along the back of the shingle ridge.
Infrastructure developed on the island includes an airstrip, which runs along almost half the southern arm (Plate 4). To provide a level surface, the gutter has been infilled and a large borrow pit excavated further south. More borrow pits are located on the northern arm of the island.
Due to its low-lying nature, Fongafale is extremely susceptible to elevated water levels, including high tides and storm surges. Under most conditions, the rock platform on the exposed side of the island provides significant protection against wave action. However, the effectiveness of this protection is drastically reduced during high water levels or with long- period waves.
During TC Bebe in October 1972, the most significant sources of damage were developed by the high storm surge and wave overtopping from the southeast. Direct wave impact was relatively minor, occurring towards the southern tip of the island, largely associated with shear between islands and crest deflation at low points.
When considering possible cyclone impacts, it is important to note that the island shoreline may be strongly dynamic. Fine material, such as that accumulated in the swash zone, is likely to be rapidly eroded during storm events, with any remaining larger sediment reworked according to the storm wave and surge sequence. The most significant shoreline impact during TC Bebe was large-scale deposition on the outer side of the shore platform, forming an extensive rubble rampart (Maragos et al, 1973). Progressive shoreward movement of the rubble mass has occurred over subsequent years, combined with gradual net erosion (Baines et al, 1974 [2]; Baines & McLean, 1976 a [3] & b [4]). This behaviour illustrates the difference between cay and motu development for atolls (Bayliss-Smith, 1988; McLean & Woodroffe, 1994 [22]; Woodroffe, 2003 [36]).
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It should be noted that accumulation during a severe storm requires abundant coral formations offshore. Coral mass recovery between severe storms may take decades. Consequently, for the purpose of modelling overtopping conditions during cyclone events, a conservative approach is to consider that no additional material is accumulated.
Figure 7. Outline of Fongafale and location of cross-sections.
5
) Trans J4 Trans J5 Trans J2 Trans J3 4 3
2
Height (m-MSL Height 1
0 0 100 200 300 400 500 600 700 800 Lagoon Distance (m)
5 Trans J6 Trans J1 ) 4
3
2
Height (m-MSL Height 1
0 0 100 200 300 400 500 600 700 800 Lagoon Distance (m)
Figure 8. Cross-sections by Japanese survey team
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Plate 1. Coral rubble overlying cemented platform.
Plate 2. Shingle accumulation on southeastern shore.
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Plate 3. Low-lying land west of shingle ridge.
Plate 4. Airstrip.
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3.1 Profiles and Depositional Character
Although there is no digital terrain model (DTM) for Funafuti, there have been several surveys carried out on the island. Figure 7 shows the approximate locations of transects carried by a Japanese survey team (marked J1 to J6) and a more recent limited survey carried out as part of the current project (marked G1 to G4). The Japanese team’s sections are shown schematically in Figure 8.
It is understood that some modifications have been made along parts of the crest, particularly adjacent to the airstrip and borrow pits. The crest elevation varies between 4.2 and 5.8-m CD, being highest slightly south of the central part of the island and reducing towards the northern and southern ends. In general, the crest is relatively narrow at 10-30 m wide and consequently may be subject to deflation during over-wash events.
The leeward side of the island slopes gradually downwards from a low crest on the western side, which varies from 3.8 to 4.4-m CD. Except where the land has been excavated for borrow pits, the low-lying land is approximately 3.0-m CD immediately west of the shingle ridge.
Profiles at Funafuti reflect the depositional history of the atoll, with several layers of material, each with a different character. Surveys conducted in March 2004 distinguished six different strata:
• A strongly cemented limestone base layer, including a wave cut platform extending roughly 80-m offshore
• Sand / gravel in the swash zone, 1 – 200 mm diameter
• Very loose coral rubble in a recent storm berm, 5 – 200 mm diameter
• Loose coral rubble, 50 – 600 mm diameter, deposited following TC Bebe
• Loose, weathered coral rubble, 50 – 600 mm diameter, believed deposited by storms within the last 4,000 years.
• A mixed grade of material accumulated on the lee side, including finer sediments.
It is significant to note that the profile behaviour is strongly dynamic during storm events. Finer material, such as that accumulated in the swash zone, is likely to be rapidly eroded during storm events, with the profile of larger sediment reworked according to the storm wave and surge sequence. In addition to the existing material, there is some potential for sediment movement between the rock platform and deeper water. The dramatic accumulation produced
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during TC Bebe was coral rubble and blocks of cemented limestone, believed to be from the front of the atoll reef.
4 NUMERICAL MODELLING
4.1 Overview
A suite of numerical models has been employed to study the impacts of tropical cyclones in the Pacific. A basic description of the individual models is provided in Section 4.2 and subsequent sections describe their set-up for Funafuti and validation against reported aspects of Cyclone Bebe.
4.2 Model Descriptions
4.2.1 Cyclone Winds
The GEMS tropical cyclone model is based on the empirical model developed at the Australian Bureau of Meteorology [16]. The model treats the wind field as an asymmetric vortex.
Wind directions and speed are a function of the storm central pressure and the environmental pressure in which the storm is embedded. The spatial distribution of winds is controlled by the Radius of Maximum Winds (RMW), which defines the distance from the storm centre to the region of strongest winds. Physically, this region of strongest winds is found around the cyclone ‘eye-wall’; the eye region is the calm centre of the storm. Typically the radius of maximum winds is of the order of 30-50 km.
Another parameter (the so-called ‘B’-parameter) defines the extent to which the strongest winds are concentrated around the eye-wall or otherwise extend outwards from the storm centre.
4.2.2 Storm Surge Model
The 2-D coastal ocean model, GEMSURGE [17] solves the depth-averaged hydrodynamic equations over a region defined by detailed topographic and bathymetric information to provide currents, sea level heights due to tidal and meteorological conditions.
GEMSURGE features a grid generator to facilitate the setting up of model grids over any specified geographical region and grid resolution. It can be run over successively higher- resolution regions utilising the results of lower resolution, outer simulations as boundary conditions. This so-called ‘nesting’ technique is an economical way of maximizing grid
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resolution. The user interface is capable of incorporating output from a wide range of atmospheric models to obtain surface winds and pressure. Meteorological conditions required by GCOM2D include the 10-metre winds and surface pressure. These must be derived from a cyclone model; archived analyses; or from regional atmospheric model simulations. The winds are interpolated both spatially and temporally from the atmospheric model grid to the GCOM coarse and fine mesh grids.
The model can run with or without tidal forcing. The tidal prediction model included in GCOM2D reads the astronomical constants for each tidal constituent and calculates the tidal heights. These are applied as lateral boundary conditions in the coarse resolution GCOM2D simulation.
GEMSURGE Set-up for Funafuti
GEMSURGE has previously been established and tested over Funafuti as part of work carried out for South Pacific Sea Level Project: Phase III [13]. Model grids were established at 1km and 50 m spatial resolution based on best available topographic and bathymetric data. The extent of these grids is shown in Figure 9.
An extensive modelling program was carried out as part of the project to estimate long-term storm surge levels (ie. excluding waves) for Funafuti as part of this project. For example, Figure 10 shows the modelled storm surge component of sea level for Cyclone Bebe; the maximum surge is approximately 0.7 m.
The results of the storm surge modelling program confirmed that the storm surge process produces relatively small increases in sea level, particularly when considered in light of the impact of Cyclone Bebe. In the study of Bebe the surge, wave and tidal contributions were all determined and their relative importance is discussed in Section 3.3.
4.2.3 Wave Model (SWAN)
In order to model wave processes occurring in the near-shore zone, it is first necessary to establish the evolution of waves over the open ocean. Typically, significant tropical storm winds affect a region up to a few hundred kilometres from the storm centre, and this area changes with the movement of the storm.
Depending on the intensity of the cyclone, the winds in the affected area have the capacity to generate large ocean waves, which in turn propagate away from the generation region. In order to model these processes, it is necessary to establish a wave model over a regular grid, with a sufficiently large spatial extent to capture these processes.
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Once these large-scale wind and wave generation processes are captured, the results can then be used to focus on the interaction of the ocean scale waves with the coastlines. This latter task involves modelling the wave processes at higher spatial resolutions as the waves intersect shallower water depths.
GEMS has previously used two spectral wave models, WAM and SWAN [6] for tropical cyclone studies. Since WAM is essentially a deep water model, we have preferred to apply the third generation spectral model, SWAN which was originally developed to model near- shore processes. Later versions of SWAN have improved large scale /deep water algorithms and successfully predict tropical cyclone wave behaviour.
SWAN also incorporates a smooth nesting process in which model scales can be effectively “telescoped” from spatially coarse large scale grids to small high resolution grids established over particular areas of interest.
GEMS has validated SWAN for tropical cyclone generated wave events in Australia. Due to a lack of observational wave data, validation for Pacific storms has been more limited. However, where data has been available, the model has performed well.
Model Grids
The SWAN grids were set-up on two scales (Figure11):
• A coarse regional grid (spatial resolution 5 km) was established to capture the broad scale wave development. • A fine grid was set up over Funafuti at a spatial resolution of 200m.
By modelling at higher resolution over the near shore zone, wave-bathymetry interaction processes such as refraction and wave-breaking are more precisely defined. Grid specifications for SWAN are summarized in Table 2.
SWAN Configuration
Table 3 provides details of the SWAN parameter settings used for the modelling in the study.
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Figure 9. High resolution storm surge model grid.
5
4 Tides Crest Surge ) 3 Water Level (Surge+ Tide) 2
1
Height (m-MSL 0
-1
-2
Initial Approx Flooding eye 19-1200 20-0000 20-1200 21-0000 21-1200 described Time (UTC)
Figure 10. Modelled storm surge (green line) associated with Cyclone Bebe.
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Figure 11. Extent of SWAN grids.
Table 2. SWAN Grid Specifications Grid Name Minimum No. x Minimum No. y Res. Latitude points Longitude points (deg) Coarse -22.0 221 159.0 221 0.05 Fine -17.85 126 168.1 101 0.002 PVH -17.76 201 168.28 201 0.0002 MB1 -17.74 201 18.24 201 0.0002 MB2 -17.72 201 168.26 201 0.0002
Table 3. SWAN Model Settings.
Coordinate system Spherical Directional resolution, ∆θ 20o Frequency range 0.04 to 1.0 Hz Wave Breaking On Bottom Friction On Wave Spectrum KOMEN Set-up Off
SWAN wave model output was extracted for four representative locations around Funafuti – four on the ocean side and four in the lagoon. These locations are shown in Figure 12.
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Figure 12. SWAN model outpoints.
4.2.4 Wave Run-Up & Overtopping
Wave run-up models have been developed for a range of shoreline conditions, including beaches and shore protection systems [21] Application of these models to Fongafale is restricted due to the high degree of protection afforded by the rock platform and the comparatively dynamic nature of the shoreline. Consequently, a model has been developed to provide an estimate for the likely rates of overtopping during cyclonic events. A schematic for the model is shown in Figure 13.
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Offshore Wave Still Water Level Hs Tm θ η
Shelf Dimensions Rampart Available hr lr Formation Material V αf V φ50 wr
Wave Transmission Hs Tm
Slope Stability Runup φ50 wr αs R
Crest Stability Overtopping hc lc Q
Figure 13. Schematic for Wave Overtopping Model
Wave Transmission
Wave impacts on Fongafale are restricted by the presence of the rock shore platform. The degree of protection provided by a shelf is strongly affected by the wave conditions and the still water level. For low water conditions where the shelf is emergent, waves break at the outer edge and may possibly spill across the platform. Under high water conditions, it is possible for waves to travel directly across the shelf, generally experiencing higher friction due to the comparatively shallow depth.
Three types of conceptual model have been developed for waves passing over horizontal rock features:
(i) Depth-limited wave transmission, for very wide, submerged reef platforms [20] and [23];
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(ii) Transmission across low-crested or reef breakwaters [1] and [33];
(iii) Wave overtopping reduction produced by berm breakwaters [24], [34] and [15].
These models provide a progression from relatively broad reef platforms to narrow breakwater berms (Figure 14). The effective behaviour for any platform is strongly dependent on the water depth and incident wave conditions. In particular, the wave period (Figure 15) is a critical parameter. Synthesising the three different conceptual models, a model has been developed which enables estimation of the equivalent wave transmitted across the rock shelf under a range of conditions.
Assessment of the inshore wave climate requires transition across the platform edge. An equation has been developed to estimate this wave transformation, incorporating the shelf depth, shelf width and incident wave character.
H s B Ct = f1 f2 R Lo
s 0.5 H s 7Ro op f1 = 1− tanh R H 2π s
A fit to Allsopp & Powell wave transmission test [1] results has been doubled, representing the wave crest only, for a wave over a freeboard Ro, and subject to deep water wave steepness sop. For the purpose of assessing slope stability, the transmitted wave is effectively half that of the overtopping wave. Reduction due to shelf width B may be considered exponential
(Diegard, 1992). The estimate of transmission enables 75% transmission across B = Lo/2, with only 5% transmission for B = 6 Lo.
exp− 0.5 B B L f = max o 2 H Lo depth Hincident
Slope Stability
In order to estimate the degree of overtopping and corresponding inundation, it is necessary to recognise profile changes that may take place during a cyclone impact.
The existing foreshore rampart is comprised of five ‘typical’ geomorphic units:
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• A wave cut platform of strongly cemented limestone, almost flat at an estimated RL +1.7 m CD, which is roughly Mean Low Water Neap Tide;
• An active swash zone comprised of sand and gravel composite (1-100 mm), reaching roughly RL +3.1 m CD. This level roughly corresponds to Highest Astronomic Tide;
• A berm created by recent storms, comprised of mid-sized coral rubble (5-150 mm), very loosely packed, that varies in elevation from RL +3.3 to +4.2 m CD;
• A berm created by material mobilised during TC Bebe, comprised of larger coral rubble (50-400 mm), loosely packed, to a level of approximately RL +4.3 m CD. This material was initially deposited towards the outer edge of the wave cut platform to a level of up to RL +5.2 m CD and has progressively moved shoreward, and,
• An ‘older’ berm created by other storm events, comprised of weathered large-sized coral rubble (50-400 mm), with some soil development, roughly at level RL +4.9 m CD, with some areas higher and broader.
2.0
1.5
1.0 1.0-m, 3.0-s 2.0-m, 4.9-s
4.0-m, 6.5-s 0.5
Freeboard (m) 6.0-m, 7.7-s
0.0
-0.5 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Transmission Coefficient
Figure 14. Effect of Freeboard on Wave Transmission Stability of each portion of the slope under hydraulic action is determined by the sediment size, density and compaction. The approximate zone of hydraulic activity is defined from –
1.5 Hs to +1.0 Hs for a dynamically stable (beach) foreshore. This will vary in position with tide and surge.
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1.00
0.90 Increasing Platform Width 0.80
B 10-m 0.70 20-m 0.60 40-m 0.50 60-m 0.40 80-m 0.30 100-m Tra nsmission Coe fficie nt C 0.20
0.10
0.00 02468101214 Wave Period (sec)
Figure 15. Combined Effects of Platform Width and Wave Period on Wave Transmission
The theoretical response of a shore comprised of mobile sediment to a storm event is to flatten the active hydraulic zone. Commonly, this is achieved through erosion of the upper profile and deposition at a lower level. In some instances, additional material may be dragged shorewards by wave action, although this requires a relatively shallow bed.
active hydraulic erosion zone SWL
deposition
Figure 16. Typical storm event response for a steep profile.
Van der Meer [33] developed a general model (Figures 16, 17) for storm event response on dynamically stable profiles. This model suggests that for flatter profiles, material may be
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dragged up the beach face to produce a storm berm. The loss of carrying capacity as the wave breaks allows a net release of material to the upper profile.
deposition wave-dragged material SWL
erosion
Figure 17. Typical storm event response for a flat profile.
Accumulation of the coral rubble rampart during TC Bebe is most likely due to wave breaking at the lip of the wave cut platform. This robs carrying capacity from the incident waves and deposits larger coral rubble on the platform, towards its outer edge.
In order for such an accumulation to be repeated during a cyclone event, it is necessary that the total water level is sufficiently low to allow significant wave stress on the approach to the wave cut platform, plus that there be sufficient coral mass to produce the accumulation. Consequently, it is non-conservative to assume that a rampart will form during a design cyclone event.
In order to estimate the stability of the profile, it is necessary to determine the degree of wave action to which the mobile material is exposed. This has been estimated using the wave transmission relationship derived previously. However, both wave crest and trough movement determines slope stability. Consequently, as the rock platform effectively prevents the trough, the effective wave condition for slope stability is half the amplitude of that estimated for overtopping, which is driven by the wave crest alone.
Approximate stable grades for the shore have been estimated using the Pilarczyk (1990) and van der Meer (1988) [32] formulae for slope stability of loose aggregate (Figure 18).
H s cosα ≤ ΨuΦs b ∆m D ξm
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and
0.18 0.2 −0.1 Φs = 6.2P S N for ξm ≤ 3 where wave steepness
−0.5 ξm = 1.25Tm H s tanα
Using estimated parameters the stable slope α may be described as a function of Hs and Tm.
Relative density∆m = 1. 22
Material stability Ψu = 1. 33 Wave-structure interaction b = 0.5 Porosity P = 0.6 Damage coefficient S = 25 Wave count N = 240 (0.5 hours @ 8 second period)
50
45
40
35
30 Wave Period 3 seconds to 9 seconds 25 (1 second increments)
20
15 Stable Grade (degrees) Grade Stable 10
5
0 0123456 Significant Wave Height (m)
Figure 18. Stable grade for 200-mm rubble as a function of wave height and period
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60
50
40 20-mm 50-mm Decreasing 100-mm 30 Sediment Size 200-mm 300-mm 20 400-mm Stable Grade (degrees) Grade Stable
10
0 0123456 Significant Wave Height (m)
Figure 19. Stable grade for varied rubble sizes, wave period 8 seconds
Using the material characteristics and dimensions obtained for each profile, the wave conditions at which each geomorphic structure will ‘fail’ have been estimated (Figure 19). To facilitate this, a monotonic relationship between wave height and period has been estimated, with the form:
0.5 Tm = 2.7H s +1.1
2 H s = 0.37(Tm −1.1)
From the stability relationships, the expected mean grade is a function of material size (Table 4).
Table 4. Expected mean grade.
Size 100-mm 200-mm 300-mm 400-mm Grade for H=1.5-m 1 in 14 1 in 3.7 1 in 1.9 1 in 1.3 (4.1o) (15.0o) (27.4o) (36.9o) Grade for H=2.5-m 1 in 30 1 in 7.5 1 in 3.5 1 in 2.2 (1.9o) (7.6o) (15.8o) (24.2o) Grade for H=3.5-m 1 in 45 1 in 12.5 1 in 5.5 1 in 3.3 (1.2o) (4.6o) (10.2o) (16.7o)
This suggests the specifications set out in Table5, using mean tide conditions:
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Table 5. Summary of stability relationships.
Section 1 Section 2
Swash Destabilised by Hs = 1.0 m Swash Destabilised by Hs = 1.0 m
Storm Berm Destabilised by Hs = 1.3 m Storm Destabilised by Hs = 1.3 m Berm
Bebe Berm Destabilised by Hs = 5.2 m Bebe Destabilised by Hs = 5.2 m Berm
Oldest Destabilised by Hs = 5.2 m Oldest Destabilised by Hs = 5.2 m Berm Berm Section 3 Section 4
Swash Destabilised by Hs = 1.4 m Swash Destabilised by Hs = 0.2 m
Storm Berm Destabilised by Hs = 1.7 m Storm Destabilised by Hs = 0.9 m Berm
Bebe Berm Destabilised by Hs = 2.6 m Bebe Destabilised by Hs = 1.8 m Berm
Oldest Destabilised by Hs = 3.2 m Oldest Destabilised by Hs = 1.7 m Berm Berm
From the slope stability assessment, this suggests that southern profiles Sections 3 and 4 will be significantly modified in the course of an event such as TC Bebe. The central profiles of Sections 1 and 2 are less affected by this event, although the existing storm berm will be destabilised and it is likely that the material deposited during TC Bebe would be exposed and mobilised.
Crest Stability
Wave action that causes flattening of the profile also has the capacity to cause movement of the profile crest. Assuming no additional material becomes available, profile adjustment must occur for the material perched on top of the rock platform.
For a broad crest, material may be shifted from the top to the bottom without causing deflation of the crest (Figure 20).
Figure 20. Profile flattening for a broad crest.
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For a narrow crest, any material moved from the upper profile produces crest deflation (Figure 21).
crest deflation
Figure 21. Profile flattening and crest deflation for a narrow crest.
Overtopping
A range of overtopping formulae are available and in general use (PIANC, 1992 [26]; USACE, 2001 [31]). Two formulae for rubble slopes are developed by Owen (1980) [24] and van der Meer & Janssen (1995) [34]. The formula of Owen (1980) [24] has been adopted, as it is considered more appropriate for lower beach slopes. For grades in the order of 1 in 6 to 1 in 10, the van der Meer & Janssen (1995) [32] formulae estimates approximately 25% the overtopping rates estimated by the Owen (1980) [24] formula.
The basic formula for overtopping is commonly expressed in non-dimensional form:
q Q = = aexp()− bR gH sTom where a and b are coefficients dependent on gradient and R is non-dimensional freeboard,
0.5 R s 1 given by: R = c om H s 2π γ
where Rc is freeboard, Hs is significant wave height, som is wave steepness and γ is the slope roughness parameter.
Impacts of overtopping have been determined for a range of situations, including pedestrian and vehicle traffic, building stability and embankment stability (PIANC, 1992 [26]; USACE, 2001 [31]). Approximate behaviour corresponds to the following limits:
10-3 < q < 2x10-2 l/s per m Hazardous for traffic, causes minor damage to buildings q > 2x10-2 l/s per m Untrafficable, causes major damage to buildings
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2 < q < 80 l/s per m Minor damage to embankment. eg: loss of fines q > 80 l/s per m Damages embankment.
Whilst the wave overtopping model is comparatively process-driven, it is sensitive to of several key assumptions, particular the roughness parameter. To provide the best estimate of behaviour, it is necessary to match the model with observed behaviour. The most well documented severe event is the impact of TC Bebe.
The overtopping model was set up for five ocean-side and four lagoon-side locations based on the available topographic and bathymetric data. These locations are shown in Figure 32.
4.3 Model Validation – Cyclone Bebe
4.3.1 Storm Track
Figure 6 shows the archived track for Cyclone Bebe provided by the NZMS. Both synoptic considerations and application of the wind model to the track, and subsequent application of the wave model all indicate some inconsistencies between the on-the-ground information reported by Baines et al [2] and the designated track.
Accordingly, the NZMS track was slightly modified to better reflect the first-hand reports. In particular, this meant:
(i) The NZMS track was shifted approximately 10 nm to the west to allow the storm centre to pass closer to Funafuti and the temporary reduction in wind speed as the atoll was affected by the eye region, and
(ii) The storm was slowed slightly so that better match the timing of the recorded minimum pressure.
4.3.2 Model Results
The storm surge and wave models were run for the adjusted track. Figure 22 shows the broad scale wind field associated with the storm; highest waves are in the front, left quadrant of the storm, coinciding with the expected region of strongest winds. It is clear from these figures that while Funafuti is subjected to very large waves, a small shift in the storm path would have resulted in even larger waves affecting the atoll. Figure 23 shows a time series plot showing the evolution of modelled wave heights from the fine grid model run for these locations; the parameter plotted in the crest height defined as half the significant wave height. L. As expected, highest waves were at the ocean locations. However, as we will see in the
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ensuing analysis, the direction of the waves is critical, particularly with respect to the potential for overtopping and flooding. Figure 24 shows the component of the significant wave normal to the coastline at each point; and Figure 25 the computed overtopping. The location designated “Ocean South” clearly has the highest peak but the potential for overtopping will also depend on the coastal heights and lower lagoon-side values of this parameter may also be critical.
Figure 22. Track of Bebe and extent of stronger winds as the storm passes Funafuti.
The main concentration of this part of the study was on the ocean waves off southern Funafuti (corresponding to location of the flooding). Figure 26 shows the time series of wind and significant wave plots for the “Ocean South” location. The wind plot clearly delineates the passage of the cyclone eye and the maximum waves occur ahead of the eye with the strongest winds near the eye wall.
The wave plot for the ocean point is also shown against time series of the modelled storm surge and tides (Figure 27). Again, the wave crest height is plotted to show the processes relative to mean sea level.
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Figure 23. Evolution of broad scale wave field with approach of Cyclone Bebe towards Funafuti.
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The storm surge time series is also included on this plot. The tides shown are based on the GEMS TideTrak system that was established for Tuvalu as part of the Phase III Sea Level Project [13]. A summation of the elements is also included on the graph to indicate the timing of their combined impacts. Key incidents described in Baines et al [2] are annotated on the diagram.
This diagram indicates that the initial flooding described in Baines et al commenced near high tide on the afternoon of 21 October but well before the maximum waves. However, the apparently large flooding described later in the evening occurs after the wave maximum around the time of the storm surge as the tide on a rising tide. The model output shown in Figure 27 does not specifically account for storm run-up and overtopping.
This is now considered. Figure 28 shows a direct comparison of the uncorrected wave crest and that corrected to the component normal to the shoreline. There is not a great difference between the two as the wave direction through this period was between 120 and 160 degrees. However, the “corrected” peak is narrower and the on-shore wave component is a little lower leading up to the peak.
Figure 29 shows a comparison of the “total sea level” for the corrected and uncorrected cases. This shows that the peak for the corrected time series is later than for the corresponding uncorrected peak and that this corrected peak occurs close to the time of the reported “large wave” flooding.
While the actual degree of overtopping is directly related to the sea level and on-shore wave component, this is not a linear relationship and must therefore be computed from the models described earlier.
The impact of these wave conditions is strongly modified by the presence of the wave cut platform and its relative depth. Consequently, the corresponding water level is also critical. Presence of the wave cut platform at the approximate level of RL +1.7 m CD determines that the still water level (SWL) remains below the platform for a water level below the relative tide level -0.3 m MSL. From the modelled water levels, this suggests strong depth restrictions upon the wave impact.
Applying the wave transformation to the incident offshore wave climate (SWAN), a significant wave of up to 3.6 m height has been estimated to affect the shore face from the modelling of wave conditions offshore (Figure 30), and transformed onshore (Figure 31), during TC Bebe. Based on this, analysis of overtopping rates has been carried out for 9
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locations around Fongafale (Figure 32). Modelled overtopping discharge during TC Bebe for three representative regions of Fongafale is shown in Figure 33.
5.0 Ocean North 4.5 Ocean South 4.0 Lagoon South Lagoon North 3.5
3.0
2.5
2.0 Sea level (MSL) level Sea 1.5
1.0
0.5
0.0 10/20/72 0:00 10/21/72 0:00 10/22/72 0:00 Local Time (UTC+12hrs)
Figure 24. Combined sea level and wave crest height, corrected for normal component to shore line at Locations 1, 2 (ocean side) 3 and 4 (lagoon side).
5.0 Ocean North 4.5 Ocean South 4.0 Lagoon South Lagoon North 3.5
3.0
2.5
2.0 Sea level (MSL) level Sea 1.5
1.0
0.5
0.0 10/20/72 0:00 10/21/72 0:00 10/22/72 0:00 Local Time (UTC+12hrs)
Figure 25. Computed evolution of overtopping at Locations 1, 2 (ocean side) 3 and 4 (lagoon side) during Cyclone Bebe.
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45 5
40 Wind Speed 4.5 Wave Crest 4 35 3.5 30 3 25 2.5 20 2
Wind Speed (m/s) Speed Wind 15 1.5 Sig Wave Height (m)
10 1
5 0.5
0 0 10/20/72 12:00 10/21/72 0:00 10/21/72 12:00 10/22/72 0:00 10/22/72 12:00
Figure 26. Comparison of significant wave height with wind speed
5.0 Tides Major flooding 4.0 Wave Crest Surge
3.0 Combined
2.0
1.0 Sea level (MSL) Sea 0.0
-1.0 Initial flooding Storm Eye -2.0 10/20/72 0:00 10/21/72 0:00 10/22/72 0:00 Local Time (UTC+12hrs)
Figure 27. Relative sea level heights: Tide, Storm Surge, Wave Crest.
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5.0 Directional 4.0 Non Directional
3.0
2.0
Sea level(MSL) 1.0
0.0
-1.0 10/20/72 0:00 10/21/72 0:00 10/22/72 0:00 Local Time (UTC+12hrs)
Figure 28. Comparison of wave crest height, corrected and uncorrected for normal component to shore line (southeast Funafuti).
5.0 Directional 4.0 Non Directional 3.0
2.0
1.0 Sea level (MSL) 0.0
-1.0
-2.0 10/20/72 0:00 10/21/72 0:00 10/22/72 0:00 Local Time (UTC+12hrs)
Figure 29. Comparison of combined sea level and wave crest height, corrected and uncorrected for normal component to shore line (southeast Funafuti).
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9 9
8 8
7 7 Wave Period 6 6
5 5
4 4
3 3 (s) Period Wave Wave Height Significant Wave Height (m) 2 2
1 1
0 0 19/10/72 19/10/72 20/10/72 20/10/72 21/10/72 21/10/72 22/10/72 0:00 12:00 0:00 12:00 0:00 12:00 0:00
Figure 30. Modelled wave conditions through TC Bebe (Oct 1972)
10 2.5
9 2.0
8 1.5 Water Level 7 1.0
6 0.5 Inshore
5 0.0 and
4 -0.5 Offshore Offshore 3 -1.0 Water Level MSL)(m Wave Height Significant Wave Height (m) Wave Height Significant 2 -1.5
1 -2.0
0 -2.5 19/10/72 19/10/72 20/10/72 20/10/72 21/10/72 21/10/72 22/10/72 0:00 12:00 0:00 12:00 0:00 12:00 0:00
Figure 31. Modelled Wave Transformation.
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Figure 32. Locations for computation of overtopping rates.
100.00 Southern South Central Northern 10.00 )
1.00
0.10 Overtopping Rate (l/s/m
0.01
0.00 10/20/72 0:00 10/20/72 12:00 10/21/72 0:00 10/21/72 12:00 10/22/72 0:00 Local Time
Figure 33. Modelled Overtopping Discharge During TC Bebe.
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4.3.3 Quantification of Flooding: Implied Food Levels
The available topographic detail for Funafuti is not sufficient to support dynamic flood inundation modelling. However, estimates of flood levels have been made based on a desk- top analysis of the cross-section data described in Section 3.
Based on the data shown in Figure 7, an average cross-section for the area between sections J2 and J5 was computed and this is shown in Figure 34. This gives an average distance between the mean lagoon and ocean-side berms of approximately 300m. Taking a mean overtopping rate of 50 litres/second/metre over a period of three hours implies total inundation of 540 cubic metres per metre of cross-section or an average equivalent depth of 1.4m (above ground level). This analysis does take into account percolation source or sink rates, but gives a flood level consistent with the observed levels of flooding with Bebe.
Table 6 gives equivalent flood depths for a range of inundation rates and periods of impact, where overflow is assumed to occur at 1.5m.
3.5 3 2.5 2 1.5 1
Height (aboveMSL)Height 0.5 0 1 51 101 151 201 251 301 351 401 451 Distance from lagoon(m)
Figure 34. Average cross section for southeast arm of Funafuti atoll.
Table 6. Estimated flood levels, above ground level as a function of inundation rate. Duration (h) Inundation Rate (litres/second/metre) 10 50 100 500 0.5 0.05 0.25 0.50 1.5 1.0 0.09 0.45 0.9 1.5 3.0 0.27 1.40 1.5 1.5
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5 WAVE RISK ANALYSIS
5.1 Overview
A wave risk analysis was carried out by running the SWAN coarse-fine grid model system for multiple storm tracks, covering a wide range of possible event scenarios. The wave model and run-up model results were then used to estimate overtopping levels around Funafuti based on varying tide heights. In order to include the impact of increased still water level on run-up computations, the storm surge model was also run for each event and the results incorporated into the run-up algorithms. The aim of this exercise was to provide a tool for predicting relative inundation risk for a range of storm types.
5.2 Storm Variables
The track variable settings are detailed in Table 7. Storm intensities were based on four central pressure values – 990 hPa, 970 hPa, 950 hPa and 930 hPa. It should be noted that for each run the central pressure was kept constant throughout the course of the simulation – since it is likely that storm intensity would be increasing as the storm moved southwards, this assumption will tend to overestimate the wave heights to some degree, so that the results will be conservative. We note that there are not enough storm data for the region to allow for varying storm pressure.
Because of the large number of track combinations to be covered, the speed of movement was set at a representative value of 15 km/h; faster moving storms would be expected to produce larger waves on the forward left side of the storm due to asymmetries in the wind fields.
Five primary directions were selected ranging from west-northwest to east-northeast and tracks from each direction were separated by a distance equal to one radius of maximum wind (30 km). Figure 35 shows each of the modelled tracks grouped by direction.
Table 7. Summary of cyclone specifications.
Parameter Value(s) Direction 290°, 330°, 360°,040°, 070° Forward Speed 15 km/h Radius of Maximum Wind 30 km Central Pressure 990 hPa, 970 hPa, 950 hPa, 930 hPa Track Separation 30 km
Number of Tracks per Direction 6
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Figure 35. Cyclone tracks.
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5.3 Summary of Results
The wave and storm surge models results are summarized in Tables 8 and 9 respectively. While both models were set-up to provide output data at each of the locations shown in Figure 34, the tables show data for two representative points: for the open ocean (Point 3), and for the lagoon (Point 8).
As expected, the largest wave and surges occur when the more intense cyclones pass close to Funafuti. For cyclones of Bebe-like intensity (950 hPa), slightly higher wave peaks were recorded for the northwest track 6. However, for run-up and overtopping, the direction is a critical component.
Run-up was computed for each storm case at each of the nine output locations for a range of tide levels (0.0m to 1.0m). The results of this analysis are provided in Appendix 1. The values shown for each event combination are overtopping rates and those values above 1 and 10 litres/second/metre are highlighted. Ocean side locations are marked in dark blue and lagoon locations are marked in light blue. The absolute overtopping estimates can be interpreted in the context of the typical impacts described earlier; and these overtopping estimates should be treated with some caution as they are subject to the underlying assumptions described in earlier parts of the report. However, there relative values are instructive and suggest that storms below 970 hPa have the capacity to provide significant inundation if they pass within 100 km or so of Funafuti with the risk increased considerably if the peak onshore waves occur concurrently with the high part of the tidal cycle. These results should also be considered in the context of the flooding analysis carried out in Section 4.3.3 which shows that over-topping rates greater than about 50 litres/second/metre may be sufficient to completely flood southern Funafuti.
The higher ocean waves mean that inundation from the east (as with TC Bebe) is more probable, but the results show that lagoon side inundation has the potential to be severe for a very strong cyclone with the risk again exacerbated at higher tide levels.
We note that for the same intensity cyclones (below 990 hPa), overtopping on the lagoon side (particularly at Point 8) is more relatively more likely and more severe for storms approaching from the west-southwest and these storms have the highest capacity to produce directly on- shore waves at Point 8.
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A visual summary of potential overtopping effects is provided in the matrix of Table 10, which is developed for the maximum, 1.0 m tide case. The key diagrams and explanation of the overtopping matrix is given in Figure 36
While it not clear what the potential maximum intensity of a storm that directly impacts Funafuti (that is passes with its maximum winds close to the atoll), the results suggest massive potential inundation by such a storm if it were stronger than Bebe. In the next section we provide some estimates as to event probability, but the potential extreme impact of such events requires consideration of the implications for emergency planning and response.
Table 8. Estimated maximum significant wave heights for the design cyclone tracks (ocean first, and lagoon). Track Index ENE 1 2 3 4 5 6 7 8 9 990 0.6/1.0 0.7/1.1 0.8/1.2 1.0/1.4 1.1/1.5 1.3/1.5 1.7/1.7 2.0/1.5 1.2/1.1 970 0.9/1.4 1.1/1.6 1.2/1.8 1.4/2.0 1.7/2.3 1.8/2.2 2.6/2.4 3.2/2.3 2.1/1.6 950 1.0/1.5 1.2/1.7 1.4/2.0 1.6/2.3 1.9/2.9 7.2/2.8 3.3/2.8 4.1/2.6 2.8/1.9 930 1.0/1.6 1.2/1.8 1.4/2.0 1.7/2.4 2.1/3.3 9.9/3.1 7.0/3.1 4.6/2.8 3.5/2.2 NE 1 2 3 4 5 6 7 8 9 990 0.7/0.9 0.8/1.0 0.9/1.1 1.1/1.4 1.2/1.5 1.3/1.4 1.4/1.4 1.4/1.2 1.5/1.2 970 1.0/1.4 1.2/1.5 1.4/1.8 1.6/2.1 1.9/2.6 1.7/2.4 2.2/2.1 2.3/1.6 2.4/1.6 950 1.2/1.6 1.3/1.8 1.6/2.1 1.9/2.6 7.1/3.3 7.1/3.1 7.3/2.6 3.2/2 3.1/1.8 930 1.2/1.6 1.4/1.8 1.7/2.2 2.0/3.7 8.3/4 12.8/3. 7.5/2.9 3.9/2.3 3.6/2.0 N 1 2 3 4 5 6 7 8 9 990 .7/.7 .9/.9 1.1/1 1.3/1.1 1.5/1.3 1.4/1.3 1.1/1.2 1.2/1 1.2/.9 970 1.2/1.2 1.4/1.4 1.7/1.6 2-Feb 2.1/2.5 1.7/2.1 1.9/1.9 2.1/1.6 2/1.2 950 1.4/1.5 1.6/1.7 2-Feb 2.4/2.6 9.7/2.9 7.6/2.6 2.9/2.6 3.1/2 2.7/1.4 930 1.5/1.7 1.7/2.4 2.1/2.8 2.6/2.9 10.6/3. 2.4/3.4 7.4/3 3.7/2.2 3.2/1.5 NW 1 2 3 4 5 6 7 8 9 990 1.1/.8 1.3/.9 1.5/1 1.7/1.1 1.7/1.2 1.5/.9 1.2/.8 1.1/.7 1.2/.6 970 1.8/1.3 2/1.5 2.4/1.6 2.7/2 2.9/2.5 7.1/1.7 1.7/1.4 1.9/1.2 1.8/1 950 2.1/1.6 2.4/1.9 2.8/2.6 7.6/2.6 7.7/3 8.2/2.4 6.8/2 2.6/1.6 2.5/1.2 930 2.2/2.3 2.6/2.6 6.4/2.8 9.1/2.9 7.6/3.2 10.2/2. 7.5/2.7 6.1/1.8 3.1/1.4 7 WNW 1 2 3 4 5 6 7 8 9 990 1.3/.7 2.4/1.4 2.4/1.4 2.5/1.3 2.2/1.1 1.7/.7 1.4/.6 1.2/.5 1.1/.5 970 3.6/1.9 4.1/2.1 4.2/2.2 4.1/2.3 3.5/1.9 2.6/1.3 2/1.3 1.6/1 1.6/.8 950 4.9/2.4 5.6/2.6 5.9/2.7 6.3/2.8 8.3/2.6 8/2.1 2.4/1.8 2.1/1.5 2/1.2 930 6.2/2.8 7.1/2.9 7.4/3 6.5/3.1 8.5/3 9.7/2.4 6.7/2.3 2.5/1.9 2.6/1.6
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Table 9. Estimated storm surge heights for the design cyclone tracks (ocean and lagoon). Track Index ENE 1 2 3 4 5 6 7 8 9 990 .02/.1 .02/.1 .02/.1 .03/.12 .08/.16 .16/.21 .08/.1 .04/.08 .02/.08 970 .02/.1 .03/.1 .03/.11 .05/.13 .14/.27 .38/.42 .19/.16 .06/.09 .03/.08 950 .03/.1 .03/.13 .03/.13 .06/.18 .2/.35 .6/.59 .3/.24 .09/.08 .03/.08 930 .03/.13 .03/.15 .03/.16 .09/.2 .27/.46 .83/.81 .42/.29 .13/.08 .04/.08 NE 1 2 3 4 5 6 7 8 9 990 .02/.09 .02/.09 .02/.1 .02/.09 .07/.15 .15/.21 .07/.12 .02/.08 .02/.08 970 .02/.08 .03/.09 .02/.1 .03/.11 .13/.2 .36/.42 .17/.15 .05/.07 .02/.06 950 .02/.11 .03/.12 .02/.11 .06/.14 .19/.26 .57/.59 .27/.2 .06/.06 .02/.06 930 .03/.08 .02/.12 .03/.15 .06/.18 .24/.33 .79/.81 .36/.26 .08/.07 .02/.06 N 1 2 3 4 5 6 7 8 9 990 .02/.08 .02/.08 .02/.07 .03/.09 .07/.11 .16/.2 .07/.1 .02/.07 .03/.07 970 .03/.08 .02/.08 .03/.08 .05/.11 .15/.16 .38/.41 .14/.15 .02/.07 .02/.08 950 .03/.09 .03/.08 .03/.1 .08/.12 .23/.22 .59/.6 .22/.21 .02/.09 .03/.07 930 .03/.08 .03/.1 .04/.09 .1/.12 .31/.27 .82/.79 .29/.3 .02/.1 .03/.07 NW 1 2 3 4 5 6 7 8 9 990 .03/.08 .03/.07 .03/.08 .04/.08 .08/.1 .16/.2 .07/.12 .03/.08 .03/.08 970 .03/.06 .03/.06 .04/.06 .07/.07 .18/.14 .37/.37 .13/.17 .03/.1 .04/.08 950 .03/.07 .03/.06 .06/.07 .11/.09 .27/.17 .58/.57 .19/.28 .03/.1 .04/.07 930 .03/.07 .04/.07 .07/.06 .14/.06 .37/.2 .8/.77 .26/.32 .03/.1 .03/.08 WNW 1 2 3 4 5 6 7 8 9 990 .03/.07 .03/.07 .04/.07 .05/.07 .08/.1 .16/.19 .08/.13 .03/.08 .03/.08 970 .04/.08 .04/.08 .07/.07 .09/.07 .18/.11 .36/.41 .15/.22 .02/.1 .04/.08 950 .04/.08 .05/.07 .1/.07 .13/.07 .3/.16 .58/.54 .23/.34 .04/.1 .04/.1 930 .04/.07 .05/.07 .13/.06 .17/.06 .41/.2 .81/.74 .3/.43 .03/.14 .02/.08
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ENE (070) track @ 930 hPa
1000
100
10 Ocean-side 1 Ocean-side 2 Ocean-side 3 (litres/second/metre) Ocean-side 4 Overtopping Rate at Station Station at Rate Overtopping 1 Ocean-side 5 Lagoon-side 6 Lagoon-side 7 Station No. Lagoon-side 8 Lagoon-side 9 Parallel Track No. Flooding Scale
Figure 36. Key Diagram to Overtopping Matrix (see next page) Explanation of Key Diagram - Overtopping Rate: 1. Example shown is for a cyclone with a central pressure of 930 hPa, tracking from ENE (070°) towards WSW (250°) for a tide level at Funafuti of 1.0 m above MSL. 2. Potential parallel tracks in the vicinity of Funafuti (see track diagram below) are shown as 1-9, with track 6 representing a direct hit on Funafuti. 3. Pink flooding scale marker shows approximate rate (50 litres/second/metre) at which general flooding is likely to occur in southern Funafuti (see Section 4.3.3 for details of TC Bebe flooding). 4. Red flooding scale marker shows approximate rate (200 litres/second/metre) at which major structural damage is likely to occur in southern Funafuti. 5. Ocean-side modelled observation stations 1-5 are shown in dark blue. 6. Lagoon-side modelled observation stations 6-9 are shown in light blue. 7. Example demonstrates that, for this given track direction and central pressure, sporadic overtopping is expected at some locations on the lagoon side of Funafuti, particularly from a direct hit (6) or tracks lying to the south of Funafuti (7-9). General overtopping is expected on the ocean side, but particularly from tracks lying to the north of Funafuti (1-5).
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Table 10. Matrix of Cyclone Central Pressures versus Approach Tracks showing Overtopping Potential at Funafuti, Tuvalu (tide level: 1.0 m above MSL)
Central Pressure 990 hPa 970 hPa 950 hPa 930 hPa Tracking from:
WNW (290) track @ 990 hPa WNW (290) track @ 970 hPa WNW (290) track @ 950 hPa WNW (290) track @ 930 hPa
1000 1000 1000 1000
100 100 WNW 100 100
10 10 (290°) 10 (litres/minute) 10 (litres/minute) (litres/minute) (litres/minute) O Oc O Oce Station at Rate Overtopping Overtopping Rate at Station Overtopping Rate at Station Station at Rate Overtopping Ocea
Overtopping Rate at Station Station at Rate Overtopping Oce Oc Ocean- 1 1 Ocean- 1 1 Ocean Lago Lagoon-s Lago o n-si Lagoon-s Lago on-side Lagoon Lagoon-side Lagoo n-side Lagoon-side 8 Lagoon-sid Lago on-side 8 Lagoo n-side 8 Lagoon-side 9 Lagoon-side 9 Lago o n-side 9 Lagoo n-side 9 Parallel Track No. Parallel Track No. Parallel Track No. Parallel Track No. Flooding Scale Flooding Scale Flooding Scale Flooding Scale
NW (330) track @ 990 hPa NW (330) track @ 970 hPa NW (330) track @ 950 hPa NW (330) track @ 930 hPa
1000 1000 1000 1000
NW 100 100 100 100
(330°) 10 10 10 10 (litres/minute) (litres/minute) (litres/minute) (litres/minute)
O O O Overtopping Rate at Station Station at Rate Overtopping
Oce Oce Station at Rate Overtopping Oce Overtopping Rateat Station Station at Rate Overtopping 1 Oc 1 Ocean 1 Ocean 1 Ocean Lago Lagoon-s Lagoon-s Lagoon-s Lagoon Lago on-side Lagoo n-side Lagoon-side Lagoon-sid Lagoon-side 8 Lagoon-side 8 Lagoon-side 8 Lago o n-side 9 Lago o n-side 9 Lagoo n-side 9 Lagoon-side 9 Parallel Track No. Parallel Track No. Parallel Track No. Parallel Track No. Flooding Scale Flooding Scale Flooding Scale Flooding Scale
N (360) track @ 990 hPa N (360) track @ 970 hPa N (360) track @ 950 hPa N (360) track @ 930 hPa
1000 1000 1000 1000
N 100 100 100 100
(360°) 10 10 10 10 (litres/minute) (litres/minute) (litres/minute) (litres/minute)
O O Oc
Overtopping Rate at Station Station at Rate Overtopping Oce Ocea Overtopping Rate at Station Station at Rate Overtopping Oce Overtopping Rate at Station Station at Rate Overtopping Overtopping Rate at Station Station at Rate Overtopping Ocean- 1 Oc 1 1 Ocean- 1 Ocean- Lago Lagoon-s Lagoon-s Lago o n-s Lagoon Lagoo n-side Lagoo n-side Lago on-side Lagoon-sid Lago o n-side 8 Lagoo n-side 8 Lagoon-side 8 Lagoon-side 9 Lagoo n-side 9 Lago o n-side 9 Lagoo n-side 9 Parallel Track No. Parallel Track No. Parallel Track No. Parallel Track No. Flooding Scale Flooding Scale Flooding Scale Flooding Scale
NE (030) track @ 990 hPa NE (030) track @ 970 hPa NE (030) track @ 950 hPa NE (030) track @ 930 hPa
1000 1000 1000 1000
NE 100 100 100 100
(030°) 10 10 10 10 (litres/minute) (litres/minute) (litres/minute) (litres/minute)
O O Oc Oce Oce
Overtopping Rate at Station Station at Rate Overtopping Overtopping Rate at Station Station at Rate Overtopping Ocea Overtopping Rate at Station Station at Rate Overtopping Ocean 1 Oc 1 1 Ocean 1 Ocean- Lago Lagoon-s Lagoon-s Lagoon-s Lagoon Lago on-side Lagoo n-side Lagoo n-side Lagoon-sid Lagoon-side 8 Lago o n-side 8 Lagoon-side 8 Lagoon-side 9 Lago o n-side 9 Lago on-side 9 Lago o n-side 9 Parallel Track No. Parallel Track No. Parallel Track No. Parallel Track No. Flooding Scale Flooding Scale Flooding Scale Flooding Scale
ENE (070) track @ 990 hPa ENE (070) track @ 970 hPa ENE (070) track @ 950 hPa ENE (070) track @ 930 hPa
1000 1000 1000 1000
ENE 100 100 100 100
(070°) 10 10 10 10 (litres/minute) (litres/minute) (litres/minute) (litres/minute)
O O O
Oce Oce Station at Rate Overtopping Oce Overtopping Rate at Station Station at Rate Overtopping Station at Rate Overtopping Overtopping Rate at Station Station at Rate Overtopping Ocean 1 Oc 1 Ocean 1 Ocean 1 Lago Lagoon-s Lagoon-s Lagoon-s Lagoon- Lago o n-side Lago on-side Lagoon-side Lago o n-sid Lago on-side 8 Lagoon-side 8 Lagoon-side 8 Lagoon-side 9 Lago o n-side 9 Lago on-side 9 Lagoon-side 9 Parallel Track No. Parallel Track No. Parallel Track No. Parallel Track No. Flooding Scale Flooding Scale Flooding Scale Flooding Scale
Tuvalu Wave Risk Study 12 1 5.4 Event Probability
Application of cyclone climatology statistics to predict event frequency is particularly problematic for Tuvalu due to the relatively small number of events in the cyclone database. However, such an analysis has been previously carried out by GEMS as part of the South Pacific Sea Level Project: Phase III [13].
This analysis sought to assign overall storm frequency for the Tuvalu region on a per annum basis and then assign relative frequencies for storm intensity and storm direction. By integrating these statistics with the results of the modelling program in the current project and an analysis of the relative frequency of tide levels, average recurrence intervals have been computed for overtopping for the ocean and lagoon sides (Point 3 and Point 8).
In order to compute over-topping frequency, it was necessary to integrate the cyclone probabilities derived from the Sea Level Project with probabilities of tidal exceedance and the results of the modelling described in the previous section.
Tidal probabilities were calculated by running the TideTrak system, also developed as part of the Sea Level Project over the full astronomical cycle. Figure 37 shows the probability of occurrence for tidal bins at 0.2 metre intervals.
0.1 0.09 0.08 0.07 0.06 0.05 0.04 Probability 0.03 0.02 0.01 0 0.1 0.3 0.5 0.7 0.9 1.1 -1.1 -0.9 -0.7 -0.5 -0.3 -0.1 Tide height (m-MSL)
Figure 37. Relative frequency of tide heights at Funafuti Over-topping was computed for each combination of cyclone and tide and the joint probability of each event combination was aggregated for over-topping level in increments of 0.1 litre/second/metre. The joint probabilities were then converted to return periods (based on the storm frequency analyses of the Sea Level Project. The integrated results are shown in the first column of Table 11. GEMS – Global Environmental Modelling Systems Report 29/04
Table 11. Average recurrence Interval (years) for a range of over-topping rates for mean sea level based on current climate, and IPCC mean predictions for 2050 and 2100. Overtopping Current Climate 2050 2100
(l/sec/m) Ocean Lagoon Ocean Lagoon Ocean Lagoon
0.1 73 209 60 144 43 94 1 258 831 202 600 130 335 5 393 3338 337 1702 219 850 10 452 6052 395 2661 304 1304 50 949 >105 737 53816 510 12845 100 1417 >106 1074 >105 708 23067 500 4291 2973 1876 >106 1000 7131 5416 3094
The results indicate that a major inundation event such as Bebe (overtopping > 50) would be expected to occur every 1000 years or so. This is reasonable based on the evidence of the limited storm data base – in the last 30 years there has only been once storm in the region below 980 hPa and this directly impacted the atoll. However, we strongly caution these estimates are subject to large error bars in the absence of better climatological storm data.
5.4.1 Climate Change
We have previously stated discussed the lack of data relating to the impact of climate change on storm frequency or intensity within the South-West Pacific. Accordingly, no attempt has been made to estimate this component of climate change impact on cyclone flooding. However, the strong dependence of over-topping on still water level means that an increase in average sea level would result in higher probabilities of over-topping even if the storm climate itself is stationary.
To quantify the effect of sea level increase, the run-up probability model was run for the mid- range sea level increase predictions at 2050 and 2100 provided by the IPCC (X). These values are 0.18 and 0.45 metres respectively. Estimated return periods under the climate change predictions are shown in the second and third columns of Table 11. The results predict a doubling of risk for the 2100 mid-range prediction.
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6 SUMMARY & CONCLUSIONS
6.1 Risk at Funafuti
The general susceptibility of the low lying Tuvalu group of atolls to significant storm-tide inundation events is well known, but the processes causing inundation have not been so well understood.
This study has focused particularly on the quantifying the vulnerability of Funafuti during tropical cyclone events. The only directly impacting historic event was Cyclone Bebe, which passed just to the east of Funafuti in October 1972. This event has been used as a benchmark, both to validate wave modelling processes applied in the study and, given its severe impact, for consideration of the potential severity of more intense storms.
The study has shown that the models appear to provide good predictions of wave behaviour during the event, although there is degree of uncertainty regarding the exact sequence of events which lead to substantial flooding of the atoll. Nevertheless, the model predicts a relatively short, but very significant period of overtopping over the ocean-side berm consistent with flooding to 1 to 1.5 metres in the low-lying regions. The modelling showed that the combination of tide, storm surge and large waves combined to cause the flooding.
Having established a validated process for modelling the impact of events, a range of potential storm events was then considered – this involved running the wave model suite for events with varying storm intensity, direction of movement and proximity to Funafuti. Maximum overtopping rates were computed at several locations around Funafuti, both on the ocean and lagoon sides, for each storm event.
As might be expected, the results show that cyclones tracking close to Funafuti result have the largest impact. Similarly, more intense storms have greater impact. Storm direction was very important in determining which locations are most effected; for example, storms approaching from westerly quarter are much more likely to cause overtopping from the lagoon-side while easterly quarter storms have a relatively greater overtopping impact on the ocean-side.
Desk-top computations suggest that overtopping rates exceeding 50 litres/second/metre are likely to cause significant flooding. We note that overtopping rates approaching or exceeding 200 litres/second/metre have the potential to cause major structural damage depending on building set-backs and engineering. Since more of the Funafuti buildings are clustered on the lagoon side, these buildings may be at greater risk from storms approaching from the west.
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The modelling results suggest that major impacts may occur for storms at or below 970 hPa passing within 100 km or so of the atoll (with similar impacts for less intense storms where the associated wave maxima occur concurrently with higher tides). Given that the central pressure of Bebe was at or a little below 950 hPa, storms of such intensity are shown to be quite possible.
The question arises as to how frequently such storms are likely to occur, that is, storms of sufficient intensity and on a path conducive to producing waves with significant overtopping potential, with potentially greater devastating impact than Bebe. It has been stressed that the storm data base for the region is very limited – cyclones are not frequent at the latitude of Funafuti, and intense storms even less so. Theoretical limits on storm intensity do not shed much light on the problem, as the methodologies used do not allow for restrictions on the generating mechanisms for cyclones in the region, particularly related to the restriction of latitude.
These limitations strongly restrict the applicability of extreme value analyses to reasonably predict recurrence intervals for major events. Notwithstanding these limitations, an attempt has been made to estimate overtopping rates corresponding to a range of return periods. In making these estimates, we have effectively allowed a lower limit of 930 hPa, but this should be treated as an “educated” approximation rather than a rigorously supportable approximation.
The estimates suggest that major flooding events, of the scale of Bebe, would occur approximately every 1,000 years while damaging overtopping rates on the lagoon side would be significantly less frequent, but still possible. We consider this an important consideration from a safety perspective as high overtopping rates may result in significant structural damage to even well-engineered buildings.
It is our view that the implications of this aspect of the study results require further consideration both in respect of both infrastructure and emergency response planning.
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7 REFERENCES
[1] Allsop, N. (1983) Low-Crest Breakwaters, studies in random waves. Proceedings of Coastal Structures ’83. American Society of Civil Engineers. pp 94-107.
[2] Baines, G., Beveridge, P. & Maragos, J. (1974) Storms and island building at Funafuti Atoll, Ellice Islands. Proceedings of the Second International Coral Reef Symposium, Vol 2. Great Barrier Reef Committee, Brisbane. Pp 485-496.
[3] Baines, G. & McLean, R (1976a) Resurveys of 1972 hurricane rampart on Funafuti atoll. Search, 7. pp 36-37.
[4] Baines, G. & McLean, R. (1976b) Sequential studies of hurricane bank evolution at Funafuti atoll. Marine Geology, 21. pp M1-M8.
[5] Bayliss-Smith, T. (1988) The role of hurricanes in the development of reef islands, Ontong Java Atoll, Solomon Islands. Geographical Journal, 154. pp 377-391.
[6] Booij, N., Holthuijsen, L.H. & Ris, R.C. (1999) A Third-generation Wave Model for Coastal Regions, Part 1, Model Description and Validation, J.Geoph. Research, 104, C4, 7649-7666.
[7] Brander, R., Kench, P. & Hart, D. Spatial and temporal variations in wave characteristics across a reef platform, Warraber Island, Torres Strait, Australia. Marine Geology, 207. pp 169-184.
[8] Davison, A.C. & Smith, R.L. (1990) Models for exceedances over thresholds. J.R.Statist. Soc.B..
[9] Emanuel, K.A. (1986) An Air-sea Interaction Theory for Tropical Cyclones. Part I. J. Atmos. Sci., 42, 1062-1071.
[10] Fitchett, K. (1987) Physical Effects of Hurricane Bebe upon Funafuti Atoll, Tuvalu. Australian Geographer, 18 (1). pp 1-7.
[11] Fredsoe, J. & Diegard, R. (1982) Mechanics of coastal sediment transport. Advanced Series on Ocean Engineering. Vol 3. World Scientific, 369p.
[12] Gourlay, M. (1994) Wave transformation on a coral reef. Coastal Engineering, 23. pp 17-42.
[13] GEMS Doc M2003-2, South Pacific Sea Level and Climate Monitoring Project, Phase III: StormTrak User Manual & Training Notes, 2003.
[14] Holland, G.J. (2000) The Maximum Potential Intensity of Tropical Cyclones. J. Atmos.Sci., 54, 2519-2541.
[15] Holland, G.J. (2004) Personal Communication.
[16] Holland, G.J. (1980) An analytical model of the wind and pressure profiles in hurricanes. Mon. Wea. Rev., 108, 1212-1218.
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[17] Hubbert, G.D. & McInnes, K.L. (1999) A storm surge inundation model for coastal planning and impact studies. To appear in J. Coastal Research.
[18] International Navigation Association (2003) State-of-the-Art of Designing and Constructing Berm Breakwaters. Report of Working Group 40 of the Maritime Navigation Commission.
[19] Maharaj, R. (2001) Pacific Islands at Risk: Foreshore Development and their Vulnerability and Implications for Adaptation Strategies to Climate Change.
[20] Maragos, J., Baines, G. & Beveridge, P. (1973) Tropical cyclone creates a new land formation on Funafuti atoll. Science, 181. pp 1161-1164.
[21] McInnes, K.L. & Hubbert, G.D. (1995) Extreme Weather Events and Coastal Inundation. Proceedings Workshop on Atmospheric Hazards, Processes, Awareness and Response. University of Queensland, Brisbane, Queensland. Sept. 20-22.
[22] McLean, R. & Woodroffe, C. (1993) Coral atolls. In: (Eds) Carter,R. & Woodroffe,C. (1994) Coastal Evolution. Late Quaternary shoreline morphodynamics. Cambridge University Press.
[23] Muoz-Perez, J., Tejedor, L. & Medina, R. (1999) Equilibrium Beach Profile Model for Reef-Protected Beaches. Journal of Coastal Research. Vol 15. No 4. pp 950-957.
[24] Owen, M. (1980) Design of seawalls allowing for wave overtopping. Report No 924. Hydraulics Research Station, Wallingford, UK.
[25] Owen, M. (1982) The hydraulic design of seawall profiles. Proceedings of the Coastal Protection Conference, Institution of Civil Engineers, Thomas Telford Publishing, UK. pp 185-192.
[26] Permanent International Association of Navigational Congresses (1992) Guidelines for the Design and Construction of Flexible Revetments Incorporating Geotextiles in Marine Environment. Report of Working Group no.21 of the Permanent Technical Committee II.
[27] Pilarczyk, K. (1990) Design of Seawalls and Dikes I including overview of Revetments. Coastal Protection. Pilarczyk, K. (Ed.) A.A. Balkema Publishing, Rotterdam, Netherlands.
[28] Powell, K. & Allsop, N. (1985) Low-Crest Breakwaters, Hydraulic Performance and Stability. Report No SR 57. Hydraulics Research Station, Wallingford, UK.
[29] Trenhaile, A. (2004) Modeling the accumulation and dynamics of beaches on shore platforms. Marine Geology. Vol 206. pp 55-72.
[30] Tonkin, H., Holland, G.J., Hobrook, N. & Henderson-Sellers, A. (2000) An Evaluation of Thermodynamic Estimates of Climatological Maximum Potential Tropical Cyclone Intensity, Mon Wea Revie, Vol 128. p746.
[31] United States Army Corp of Engineers (2001) Coastal Engineering Manual.
[32] Van der Meer, J. (1988) Rock Slopes and Gravel Beaches Under Wave Attack. PhD Dissertation, Delft University of Technology, Netherlands.
Tuvalu Wave Risk Study 12 7 GEMS – Global Environmental Modelling Systems Report 29/04
[33] Van der Meer, J. & Angremond, K. (1991) Wave Transmission at Low Crested Structures. Proceedings of the Coastal Structures and Breakwaters Conference. Institution of Civil Engineers, Thomas Telford Publishing, UK. pp 25-41.
[34] Van der Meer, J. & Janssen, W. (1995) Wave Run-up and Overtopping at Dikes.In: Waves Forces on Inclined and Vertical Wall Structures. Kobayashi & Demirbilek (Eds) American Society of Civil Engineers. pp 1-27.
[35] Vanualailai, P. & Mimura, N. (2001) Technology Assessment of Coastal Protection Systems in the South Pacific Countries.
[36] Woodroffe, C. (2003) Coasts. Form, process and evolution. Cambridge University Press.
Tuvalu Wave Risk Study 12 8 GEMS – Global Environmental Modelling Systems Report 29/04
8 APPENDIX 1: OVERTOPPING TABLES
Tuvalu Wave Risk Study 12 9 GEMS – Global Environmental Modelling Systems Report 29/04
WNW Cyclones (290 deg) Pr=990hPa Pr=970hPa
Tide=0.0m (MSL) Track ID Track ID Location123456789 123456789 1 000000000 00000.014.723.350.290 2 000000000 000000.550.440.030 3 000000000 000007.41000 4 000000000 0000000.040.010 5 000000000 0000000.40.070 6 000000000 00000.031.470.070.020 7 000000000 00000.020.16000 8 000000000 00000.060.12000 9 000000000 00000.070.45000 Tide=0.25m (MSL) 1 000000000 00000.0410.367.220.760 2 000000000 000001.2810.080 3 000000000 0000016.75000 4 000000000 0000000.090.010 5 000000000 0000000.910.180 6 000000.01000 0000.010.134.620.290.090 7 000000000 0000.010.120.67000 8 000000000 00000.210.43000 9 000000.02000 0000.010.291.69000 Tide=0.5m (MSL) 1 0000000.0100 00000.1322.7115.561.960 2 000000000 00000.012.972.270.20 3 000000000 0000037.8800.010 4 000000000 0000000.190.040 5 000000000 0000002.110.470 6 000000.07000 0000.030.6214.561.150.40 7 000000000 00.010.030.070.62.9000 8 000000000 0000.030.761.58000 9 000000.1000 0000.071.266.32000 Tide=0.75m (MSL) 1 0000000.0500 0000.010.4849.8233.565.060 2 000000000 00000.026.895.130.540 3 000000.01000 0000085.6500.060 4 000000000 0000000.440.090 5 000000000 0000004.881.190 6 000000.43000 000.010.222.9245.874.541.730 7 000000000 00.070.190.392.9612.510.0300 8 000000.02000 000.030.142.785.75000 9 00000.020.58000 000.020.395.4623.68000 Tide=1.0m (MSL) 1 0 0 0 0 0.02 0.01 0.25 0.01 0 0 0 0 0.08 1.73 109.3 72.35 13.08 0 2 0000000.0100 00000.0815.9911.581.460 3 000000.03000 00000.01193.70.030.280 4 000000000 0000000.980.210 5 000000000 00000011.273.020 6 0 0 0 0.01 0.05 2.7 0.05 0.04 0 0.01 0.04 0.15 1.42 13.79 144.6 17.84 7.52 0.01 7 0 0 0 0.01 0.07 0.01 0 0 0 0.03 0.55 1.27 2.37 14.56 53.92 0.31 0 0 8 0 0 0 0 0.01 0.15 0 0 0 0 0.04 0.23 0.75 10.15 20.99 0 0 0 9 0 0 0 0 0.2 3.57 0 0 0 0 0.04 0.24 2.32 23.61 88.73 0 0 0
Tuvalu Wave Risk Study 13 0 GEMS – Global Environmental Modelling Systems Report 29/04
WNW Cyclones (290 deg) Pr=950hPa Pr=930hPa
Tide=0.0m (MSL) Track ID Track ID Location123456789 123456789 1 00000.09139.6 75.06 3.79 0 0 0 0 0.01 0.17 529.6 344.3 1.42 0.01 2 0000034.0918.960.54000000.01172.3116.60.140 3 00000.0286.452.10.11000000.852433.820.290 4 0000002.360.080000000.0316.690.690 5 000000.0214.050.750000000.7375.334.650.02 6 0 0 0 0.03 6.09 12.88 1.93 0.07 0 0 0 0.01 0.14 21.6 39.08 6.15 0.03 0 7 0 0.01 0.01 0.04 0.35 0.61 0.03 0 0 0.05 0.06 0.06 0.21 18.36 11.94 0.03 0 0 8 000.010.311.631.120000.010.030.152.6210.7136.88000 9 0000.053.192.64000000.021.0330.3122.85000 Tide=0.25m (MSL) 1 0 0 0 0.01 0.26 232.6 126.2 7.87 0 0 0 0 0.04 0.49 806.6 518 3.23 0.04 2 00000.0159.6433.231.17000000.03275.2182.30.340 3 00000.08165.6 5.24 0.32 0 00002.14892.268.430.810 4 0000004.220.160000000.0926.941.290 5 000000.0825.261.60.01000001.93121.68.790.05 6 0 0 0 0.13 15.6 33.66 5.44 0.25 0 0.01 0.01 0.03 0.53 49.46 97.71 15.53 0.12 0 7 0.01 0.05 0.05 0.18 1.29 2.52 0.14 0 0 0.21 0.23 0.24 0.77 44.09 37.27 0.14 0.01 0 8 00.010.040.874.153.370000.030.10.455.9522.7775.87000 9 000.020.229.028.7500000.010.113.0968.5563.71000 Tide=0.5m (MSL) 1 0 0 0 0.03 0.8 387.4 212.2 16.35 0 0 0 0 0.13 1.44 1234 779.4 7.34 0.14 2 00000.05104.3 58.23 2.54 0 0 0 0 0.01 0.09 439.7 284.9 0.81 0.01 3 00000.2831713.060.95000005.731519138.42.270.01 4 000000.017.530.340000000.2343.492.420.01 5 000000.2645.43.420.02000005.12196.416.620.15 6 0 0.01 0.03 0.55 39.92 87.96 15.36 0.94 0 0.03 0.05 0.15 1.94 113.3 244.3 39.21 0.5 0 7 0.07 0.24 0.23 0.79 4.84 10.43 0.65 0.01 0 0.86 0.93 0.97 2.78 105.8 116.4 0.67 0.07 0 8 0.010.050.152.510.5710.160000.130.371.3713.5448.42156.1000 9 00.010.10.9125.5229.050000.020.070.489.22155177.7000 Tide=0.75m (MSL) 1 0 0 0 0.11 2.41 645.1 356.9 33.94 0 0 0 0.01 0.45 4.21 1888 1173 16.68 0.48 2 00000.15182.5 102 5.52 0 0 0 0 0.02 0.29 702.5 445.3 1.96 0.03 3 00000.9960732.552.840000015.382586280.16.330.03 4 000000.0213.460.720000000.5970.214.530.02 5 000000.8781.617.330.070000013.57317.131.440.41 6 0.01 0.05 0.2 2.43 102.2 229.9 43.39 3.54 0 0.21 0.3 0.77 7.16 259.3 610.6 99.01 2.08 0.01 7 0.4 1.17 1.15 3.41 18.12 43.26 3.05 0.06 0 3.44 3.78 3.95 10.07 254.1 363.4 3.33 0.4 0 8 0.040.240.617.1326.9230.670000.561.354.2230.8102.9321.1000 9 0.010.080.583.8172.296.440000.110.412.1727.55350.7495.5000 Tide=1.0m (MSL) 1 0 0 0.02 0.46 7.3 1074 600.1 70.47 0.01 0 0 0.03 1.6 12.3 2889 1764 37.93 1.63 2 0 0 0 0.02 0.48 320.2 178.8 12.01 0 0 0 0 0.08 0.89 1122 696 4.72 0.09 3 00003.56116281.128.530000041.274403566.717.650.16 4 000000.0724.031.510.01000001.55113.48.480.06 5 000002.95146.7 15.68 0.23 0000035.95511.959.471.14 6 0.11 0.41 1.31 10.69 261.5 600.6 122.5 13.37 0.02 1.3 1.84 4.08 26.4 593.7 1527 250 8.63 0.1 7 2.26 5.71 5.67 14.68 67.8 179.4 14.32 0.46 0 13.83 15.31 16.15 36.46 610 1135 16.47 2.25 0 8 0.271.162.5520.3868.5592.530002.374.9912.9470.07218.9660.6000 9 0.11 0.65 3.18 15.94 204.3 320.20000.842.479.7582.31793.213820.0200
Tuvalu Wave Risk Study 13 1 GEMS – Global Environmental Modelling Systems Report 29/04
NW Cyclones (330 deg)
Pr=990hPa Pr=970hPa
Tide=0.0m (MSL) Track ID Track ID Location123456789 123456789 1 000000.02000 0000098.30.860.030.05 2 000000000 0000024.720.0800 3 000000000 00000.042.950.300 4 000000000 000001.60.70.030 5 0.0200000000 0000011.464.640.30 6 000000000 00000.20.050.0800 7 000000000 000000.01000 8 000000000 00000.010.01000 9 0 0 0 0 0 0 0 0 0 0 0 0 0.01 0.04 0.03 0 0 0 Tide=0.25m (MSL) 1 0 0 0 0 00.060 0 0 0 0 0 00.01162.52.080.090.15 2 000000000 0000042.740.2100.01 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0.13 7.17 0.85 0.01 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2.94 1.32 0.07 0 5 0.0500000000 0000021.028.860.670.01 6 0 0 0 0 0 0.01 0 0 0 0 0 0 0 0.7 0.23 0.32 0.01 0 7 000000000 00000.010.07000 8 0 0 0 0 0 0 0 0 0 0 0 0 0.01 0.03 0.03 0 0 0 9 0 0 0 0 0 0 0 0 0 0 0 0.01 0.07 0.16 0.14 0 0 0 Tide=0.5m (MSL) 1 0 0 0 0 0 0.22 0.01 0 0 0 0 0 0 0.06 268.7 5.04 0.29 0.44 2 000000.01000 0000073.90.530.020.03 3 0 0 0 0 0 0.02 0 0 0 0 0 0 0 0.44 17.4 2.4 0.03 0 4 0.01 0 0 0 0 0 0 0 0 0 0 0 0 0 5.38 2.49 0.15 0 5 0.15 0 0 0 0 0 0 0 0 0 0 0 0 0 38.55 16.92 1.54 0.03 6 0 0 0 0 0 0.05 0 0 0 0 0 0 0.02 2.48 1.14 1.26 0.08 0 7 0 0 0 0 0 0 0 0 0 0.01 0.01 0.01 0 0.09 0.45 0 0 0 8 0 0 0 0 0 0 0 0 0 0.01 0.02 0.01 0.04 0.14 0.17 0 0 0 9 0 0 0 0 0 0 0 0 0 0 0.01 0.06 0.31 0.72 0.78 0 0 0 Tide=0.75m (MSL) 1 0 0 0 0 0 0.76 0.03 0 0 0 0 0 0 0.23 444.2 12.19 0.92 1.32 2 0 0 0 0 0 0.04 0 0 0 0 0 0 0 0.01 127.8 1.35 0.05 0.1 3 000000.09000 00001.4342.226.80.130 4 0.02 0 0 0 0 0 0 0 0 0 0 0 0 0 9.88 4.69 0.33 0 5 0.41 0 0 0 0 0 0.01 0 0 0 0 0 0 0 70.7 32.29 3.5 0.08 6 0 0 0 0 0.01 0.33 0.01 0 0 0 0 0 0.16 8.79 5.65 4.86 0.42 0.02 7 0 0 0 0 0 0 0 0 0 0.04 0.07 0.05 0.04 0.55 2.81 0.01 0.02 0 8 0 0 0 0 0 0 0 0 0 0.07 0.11 0.07 0.2 0.61 0.92 0 0 0 9 0 0 0 0 0.01 0 0 0 0 0.01 0.07 0.33 1.43 3.21 4.3 0 0 0 Tide=1.0m (MSL) 1 0 0 0 0 0 2.62 0.14 0.01 0 0 0 0 0 0.9 734.3 29.47 2.9 3.95 2 0 0 0 0 0 0.13 0 0 0 0 0 0 0 0.03 220.9 3.43 0.18 0.3 3 0 0 0 0 0 0.42 0 0 0 0 0 0 0 4.7 102.4 19.28 0.56 0.02 4 0.0600000000 0000018.118.850.730.01 5 1.14 0 0 0 0 0 0.05 0 0 0 0 0 0 0 129.7 61.65 7.99 0.27 6 0 0 0 0 0.07 2.21 0.08 0.02 0 0 0 0 1.09 31.21 27.85 18.79 2.27 0.15 7 0 0 0 0 0 0.01 0 0 0 0.36 0.51 0.39 0.35 3.38 17.47 0.11 0.19 0 8 0 0 0 0 0 0 0 0 0 0.42 0.61 0.43 0.97 2.76 5.05 0 0 0 9 0 0 0 0.01 0.09 0.08 0 0 0 0.07 0.52 1.95 6.59 14.24 23.74 0 0 0 Tuvalu Wave Risk Study 13 2 GEMS – Global Environmental Modelling Systems Report 29/04
NW Cyclones (330 deg)
Pr=950hPa Pr=930hPa
Tide=0.0m (MSL) Track ID Track ID Location123456789 123456789 1 0 0 0 0 0.64 1084 7.52 0.01 0.62 0 0 0 0 2.86 2766 142.3 0 0.15 2 0 0 0 0 0.05 445.8 1.03 0 0.06 0 0 0 0 0.27 1366 38.87 0 0.01 3 0 0 0 0 8.11 24.22 18.21 0.41 0.01 0 0 0 0 77.34 758.1 109.3 2.61 0.01 4 0 0 0 0 0 13.69 20.67 1.02 0.03 0 0 0 0 0 1.84 93.54 3.53 0.2 5 0 0 0 0 0 70.88 84.83 6.23 0.31 0 0 0 0 0.04 15.8 308.4 18.02 1.58 6 0 0 0 0.48 6.66 2.95 1.91 0.23 0.02 0 0 0 8.08 37.36 41.24 10.4 1.36 0.16 7 0.1 0.08 0.01 0.01 2.27 2.31 0.02 0.01 0 1.64 1.41 0.19 0.3 6.71 44.62 0.08 0.03 0 8 0.39 0.5 0.36 0.75 4.78 0.57 0 0 0 4.77 6.29 5.34 13.02 27.23 31.69 0 0 0 9 0.02 0.07 0.17 0.43 6.03 1.03 0 0 0 0.28 0.87 2.5 9.41 51.39 16.29 0 0 0 Tide=0.25m (MSL) 1 0 0 0 0 1.59 1500 15.3 0.02 1.47 0 0 0 0 6.26 3602 227.8 0 0.41 2 0 0 0 0 0.13 640.1 2.21 0 0.16 0 0 0 0 0.64 1840 65.07 0 0.03 3 0 0 0 0 17.4 51.28 37.58 1.08 0.03 0 0 0 0.01 139.8 1231 198 6.01 0.05 4 0 0 0 0 0 22.68 32.47 1.85 0.06 0 0 0 0 0.01 3.59 136.1 5.99 0.39 5 0 0 0 0 0 117 133.2 11.41 0.69 0 0 0 0 0.1 30.94 447.1 30.72 3.17 6 0 0 0 1.47 16.21 9.51 5.29 0.76 0.08 0.01 0 0 18.59 76.93 103 24.45 3.66 0.55 7 0.35 0.29 0.05 0.04 6.38 7.9 0.08 0.03 0 4.34 3.84 0.65 1.01 17.11 113.2 0.33 0.13 0 8 1.04 1.31 0.97 1.9 10.39 1.89 0 0 0 9.69 12.6 10.98 24.74 50.1 66.78 0 0 0 9 0.07 0.27 0.6 1.38 15.18 3.93 0 0 0 0.88 2.5 6.55 21.79 104.4 48.01 0 0 0 Tide=0.5m (MSL) 1 0 0 0 0 3.95 2075 31.12 0.07 3.51 0 0 0 0 13.68 4692 364.6 0.01 1.09 2 0 0 0 0 0.36 919 4.75 0 0.4 0 0 0 0 1.51 2479 108.9 0 0.08 3 0 0 0 0 37.34 108.6 77.53 2.87 0.12 0 0 0 0.05 252.7 1999 358.9 13.85 0.17 4 0 0 0 0 0 37.56 51 3.36 0.14 0 0 0 0 0.02 7.01 198.1 10.17 0.78 5 0 0 0 0 0 193.2 209.2 20.88 1.55 0 0 0 0 0.29 60.6 648.2 52.37 6.33 6 0 0 0 4.57 39.46 30.61 14.7 2.47 0.35 0.06 0 0.01 42.81 158.4 257.2 57.47 9.89 1.86 7 1.3 1.1 0.24 0.18 17.91 27.06 0.37 0.14 0 11.46 10.51 2.27 3.41 43.6 287.3 1.38 0.55 0 8 2.77 3.41 2.63 4.8 22.57 6.31 0 0 0 19.69 25.21 22.57 46.99 92.17 140.8 0 0 0 9 0.31 1.02 2.07 4.43 38.26 14.95 0 0 0 2.82 7.24 17.17 50.47 211.9 141.5 0 0 0 Tide=0.75m (MSL) 1 0 0 0 0 9.86 2870 63.29 0.27 8.37 0 0 0 0 29.91 6110 583.5 0.07 2.92 2 0 0 0 0 0.94 1320 10.21 0.01 0.99 0 0 0 0 3.54 3340 182.4 0 0.23 3 0 0 0 0.01 80.13 229.9 159.9 7.64 0.43 0 0 0 0.19 456.9 3246 650.4 31.88 0.57 4 0 0 0 0 0 62.22 80.11 6.1 0.31 0 0 0 0 0.04 13.67 288.3 17.27 1.53 5 0 0 0 0 0.02 319 328.6 38.21 3.5 0 0 0 0 0.82 118.7 939.7 89.28 12.66 6 0.01 0 0 14.16 96.05 98.58 40.81 8.01 1.49 0.31 0.03 0.05 98.56 326.2 642.3 135.1 26.7 6.25 7 4.75 4.18 1.12 0.95 50.29 92.66 1.83 0.68 0 30.28 28.74 7.91 11.53 111.1 729.1 5.78 2.27 0 8 7.39 8.9 7.09 12.16 49.03 21 0 0 0 40.02 50.46 46.43 89.24 169.6 296.6 0 0 0 9 1.41 3.91 7.17 14.16 96.41 56.92 0 0 0 9.01 20.91 45.01 116.9 430.3 417 0 0 0 Tide=1.0m (MSL) 1 0 0 0 0.01 24.6 3970 128.7 0.97 19.96 0 0 0 0.03 65.39 7957 933.9 0.29 7.85 2 0 0 0 0 2.5 1895 21.94 0.03 2.47 0 0 0 0 8.28 4500 305.3 0.01 0.66 3 0 0 0 0.07 172 486.6 330 20.32 1.52 0 0 0 0.77 825.9 5271 1179 73.4 1.97 4 0 0 0 0 0 103.1 125.8 11.06 0.69 0 0 0 0 0.11 26.68 419.5 29.32 3.03 5 0 0 0 0 0.07 526.6 516.1 69.93 7.88 0 0 0 0 2.33 232.4 1362 152.2 25.3 6 0.1 0.01 0.03 43.86 233.8 317.5 113.3 26 6.34 1.65 0.28 0.42 226.9 671.7 1604 317.5 72.1 21.05 7 17.43 15.85 5.27 4.88 141.2 317.3 9.01 3.42 0.01 80.03 78.59 27.55 39 283.3 1850 24.28 9.36 0 8 19.69 23.21 19.11 30.78 106.5 69.95 0 0 0 81.34 101 95.49 169.5 312 625.2 0 0 0 9 6.35 15.02 24.82 45.29 242.9 216.7 0 0 0 28.79 60.41 118 270.7 873.8 1229 0 0 0 Tuvalu Wave Risk Study 13 3 GEMS – Global Environmental Modelling Systems Report 29/04
N Cyclones (360 deg)
Pr=990hPa Pr=970hPa
Tide=0.0m (MSL) Track ID Track ID Location123456789 123456789 1 000000.33000 00002.45258.70.1200 2 000000.02000 00000.2880.220.0100 3 000000000 00004.360.97000 4 0.200000000 000004.520.540.010 5 1.5800000.01000 00000.0128.773.650.120 6 000000000 0000.090.030.140.2600 7 000000000 000000.03000 8 000000000 000.0100.010000 9 000000000 00.010.020.030.030000 Tide=0.25m (MSL) 1 000000.88000 00005.35394.70.3500 2 000000.07000 00000.65127.60.0200 3 000000000 00009.72.660.0100 4 0.3900000000 000007.771.020.020 5 3.1700000.02000 00000.0349.037.050.30 6 000000000 000.020.330.120.590.8800 7 000000000 00000.010.14000 8 000000000 00.010.030.010.030000 9 000000000 00.040.070.110.150000 Tide=0.5m (MSL) 1 000002.3000 000011.69602.30.9900 2 000000.19000 00001.51203.10.0700 3 000000000 000021.577.340.0300 4 0.7800000000 0000013.361.950.060 5 6.3300000.07000 00000.183.5613.620.720 6 000000000 000.111.20.522.512.9800 7 000000000 0000.020.040.77000 8 0000000000.010.060.120.040.110000 9 0000000000.010.180.330.480.630.02000 Tide=0.75m (MSL) 1 00000.016.04000 000025.539192.860.010 2 000000.53000 00003.48323.10.2200 3 00000.010000 0000.0147.9920.240.130.010 4 1.5300000.01000 00000.0122.963.710.130 5 12.6600000.21000 00000.3142.426.31.730.01 6 0000.010.030000 000.574.422.2510.7110.1400 7 000000000 0000.170.274.210.0100 8 0000000000.080.270.50.210.50.03000 9 0000.01000000.090.871.442.072.720.21000 Tide=1.0m (MSL) 1 0 0 0 0 0.05 15.86 0 0 0 0 0 0 0.03 55.74 1402 8.25 0.04 0 2 000001.47000 00008.025140.6800 3 00000.040000 0000.07106.855.810.590.070 4 3.0300000.02000 00000.0439.467.070.310 5 25.300000.64000 00000.9242.750.824.160.05 6 0 0 0 0.09 0.26 0 0.03 0 0 0 0.03 2.85 16.24 9.79 45.65 34.47 0.04 0.03 7 000000000 0001.141.7823.060.1700 8 0000000000.441.22.031.032.230.37000 9 000.020.1000000.644.166.348.8811.722.34000
Tuvalu Wave Risk Study 13 4 GEMS – Global Environmental Modelling Systems Report 29/04
N Cyclones (360 deg)
Pr=950hPa Pr=930hPa
Tide=0.0m (MSL) Track ID Track ID Location123456789 123456789 1 0 0 0 0 119.7 1769 15.58 0.02 0 0 0 0 0.01 434.7 7203 89.57 2.22 0 2 000029.978232.7600 0000144445022.50.260 3 0 0 0 0.14 152.4 42.31 0.65 0 0 0 0 0 0.68 1639 33.94 64.41 0.14 0.02 4 00000.0536.6421.730.410.0100000728.8106.34.120.1 5 00000.5316886.662.830.0900000.071908335.920.140.91 6 0 0 0.89 1.37 2.16 0.85 4.57 0 0 0 0.01 7.58 4.58 0 126.4 27.02 0.09 0.04 7 0 0 0 0.12 0 0.22 0.01 0 0 0.01 0 0.08 0.24 0 21.49 1.11 0.01 0 8 0.14 0.54 0.75 0.26 0.22 0.02 0 0 0 2.84 9 12.99 2.06 4.68 15.17 0 0 0 9 0.06 0.46 0.75 0.48 0.51 0.06 0 0 0 0.94 6.86 7.82 1.75 7.23 5.61 0 0 0 Tide=0.25m (MSL) 1 0 0 0 0.02 188.7 2368 29.47 0.06 0 0 0 0 0.05 621.5 8835 147.5 4.72 0 2 000049.6711395.4800 0000215.3560138.740.590 3 0 0 0 0.4 259.7 87.5 1.74 0 0 0 0 0 1.74 2367 77.09 120.2 0.4 0.07 4 00000.156.7833.880.780.0200000.01967.9152.96.880.22 5 00001.21257.3135.15.440.2200000.22509481.233.781.9 6 0 0 2.51 3.74 5.86 3.23 11.57 0.01 0.01 0 0.03 16.92 10.96 0 263 58.03 0.33 0.14 7 0 0 0 0.45 0.02 1.05 0.05 0 0 0.03 0 0.3 0.8 0 59.17 3.47 0.05 0 8 0.41 1.38 1.86 0.73 0.66 0.1 0 0 0 6.07 17.21 23.96 4.66 10.23 35.25 0 0 0 9 0.23 1.41 2.18 1.49 1.67 0.33 0 0 0 2.64 15.73 17.73 4.72 17.92 19.34 0 0 0 Tide=0.5m (MSL) 1 0 0 0 0.07 297.3 3169 55.75 0.19 0 0 0 0 0.17 888.5 10838 242.9 10.04 0 2 0 0 0 0 82.48 1575 10.87 0.01 0 0 0 0 0.01 321.9 7050 66.7 1.33 0 3 0 0 0 1.16 442.8 180.9 4.67 0.02 0.02 0 0 0 4.46 3419 175.1 224.4 1.14 0.23 4 00000.2387.9952.821.470.0400000.031285219.811.510.44 5 00002.75394.2210.710.440.5400000.533298689.356.653.96 6 0 0.02 7.07 10.2 15.9 12.27 29.28 0.07 0.05 0 0.14 37.74 26.26 0 547.2 124.6 1.23 0.58 7 0 0 0.01 1.63 0.14 5.01 0.24 0 0 0.13 0.01 1.12 2.68 0 162.9 10.88 0.24 0 8 1.2 3.49 4.59 2.06 2 0.56 0 0 0 12.95 32.9 44.18 10.53 22.4 81.93 0 0 0 9 0.86 4.27 6.38 4.65 5.45 1.96 0 0 0 7.41 36.08 40.18 12.72 44.4 66.71 0 0 0 Tide=0.75m (MSL) 1 0 0 0 0.25 468.6 4241 105.5 0.61 0 0 0 0 0.59 1270 13295 399.9 21.34 0.01 2 0 0 0 0.01 137 2180 21.55 0.03 0 0 0 0 0.03 481.3 8873 114.8 2.99 0 3 0 0 0 3.36 754.9 374.1 12.53 0.08 0.08 0 0 0 11.44 4938 397.6 418.8 3.25 0.76 4 00000.51136.482.362.80.100000.07170731619.250.91 5 00006.25603.8328.520.051.3300001.464336987.495.028.25 6 0 0.11 19.9 27.82 43.16 46.62 74.13 0.37 0.27 0 0.69 84.22 62.91 0 1138 267.7 4.51 2.32 7 0.02 0 0.05 5.9 0.79 23.85 1.31 0 0 0.63 0.07 4.19 9.01 0 448.7 34.12 1.15 0 8 3.53 8.85 11.35 5.77 6 3.1 0 0 0 27.66 62.91 81.47 23.78 49.04 190.4 0 0 0 9 3.3 12.96 18.66 14.51 17.77 11.67 0 0 0 20.75 82.76 91.05 34.27 110 230.1 0 0 0 Tide=1.0m (MSL) 1 0 0 0 0.94 738.4 5676 199.5 1.97 0 0 0 0 2.04 1816 16308 658.5 45.37 0.06 2 0 0 0 0.03 227.4 3016 42.75 0.11 0 0 0 0 0.11 719.6 11168 197.7 6.7 0 3 0 0 0.01 9.73 1287 773.6 33.61 0.33 0.33 0 0 0.02 29.31 7133 903 781.7 9.28 2.54 4 00001.14211.3128.45.330.2300000.182267454.332.181.87 5 000014.19924.9512.338.523.2900003.9757011414159.417.22 6 0 0.76 55.99 75.88 117.2 177.2 187.7 2.1 1.58 0.01 3.34 187.9 150.7 0 2368 574.9 16.54 9.31 7 0.2 0.04 0.42 21.33 4.58 113.4 7.02 0.01 0 3.14 0.52 15.63 30.3 0 1236 107 5.49 0.01 8 10.39 22.4 28.07 16.17 18.05 17.2 0 0 0 59.04 120.3 150.2 53.71 107.4 442.4 0 0 0 9 12.63 39.36 54.56 45.23 57.9 69.36 0 0 0 58.13 189.8 206.4 92.38 272.6 793.6 0 0 0
Tuvalu Wave Risk Study 13 5 GEMS – Global Environmental Modelling Systems Report 29/04
NE Cyclones(W413 030 deg)
Pr=990hPa Pr=970hPa
Tide=0.0m (MSL) Track ID Track ID Location123456789 123456789 1 0 0 0 0.01 4.53 2.09 0 0 0 0 0 0.1 17.5 573 551.8 0 0 0 2 00000.630.24000 000.012.98221.1205.8000 3 000000000 000.030.110.0694.961.070.020 4 00000.010000 0000.0115.570.171.330.170.01 5 00000.110000 0000.0871.121.728.351.420.15 6 000000000 00.060000.010.470.030 7 000000000 000.01000000 8 0000000000.010.130.480.130.670000 9 0000000000.020.180.320.060.180000 Tide=0.25m (MSL) 1 0 0 00.039.224.650 0 0 0 00.2931.5802.8792.20 0 0 2 00001.350.55000 000.025.67321.5306.7000 3 000000.01000 000.110.310.19173.82.680.080 4 00000.020000 0000.0124.450.362.40.330.02 5 0 0 0 0 0.26 0.01 0.01 0 0 0 0 0 0.21 110.9 3.69 15.11 2.87 0.35 6 000000000 00.220000.041.480.130 7 000000000 00.010.04000000 8 0000000000.040.381.230.41.710000 9 0000000000.080.61.010.240.630000 Tide=0.5m (MSL) 1 0 0 0 0.11 18.75 10.34 0 0 0 0 0 0.81 56.72 1126 1137 0 0 0.02 2 0 0 0 0 2.89 1.3 0 0 0 0 0 0.05 10.78 467.6 457.1 0 0 0 3 000000.06000 00.010.340.920.59318.16.720.260.02 4 00000.040000 0000.0338.40.764.320.670.06 5 0 0 0 0 0.64 0.02 0.05 0 0 0 0 0 0.52 172.9 7.91 27.35 5.78 0.84 6 0000000000.010.830000.224.730.530 7 000000000 00.030.2000.02000 8 0000000000.151.123.141.164.350000 9 0000000000.3323.170.922.220000 Tide=0.75m (MSL) 1 0 0 0 0.39 38.15 22.98 0.01 0 0 0 0.01 2.24 102.1 1579 1633 0.01 0.01 0.08 2 0 0 0 0.02 6.19 3.04 0 0 0 0 0 0.15 20.52 680 681.1 0 0 0 3 000000.24000 00.031.092.671.87582.116.840.850.09 4 0 0 0 0 0.1 0 0.01 0 0 0 0 0 0.08 60.29 1.61 7.78 1.33 0.13 5 0 0 0 0 1.59 0.06 0.15 0 0 0 0 0 1.3 269.5 16.95 49.52 11.65 1.99 6 0000000000.063.070001.415.072.210 7 000000000 00.20.94000.230.0500 8 000.010.010.0100000.583.267.993.411.10000 9 00.010.040.020.0100001.436.659.943.457.780000 Tide=1.0m (MSL) 1 0 0 0 1.37 77.59 51.05 0.06 0.01 0 0 0.06 6.2 183.9 2216 2344 0.05 0.04 0.33 2 0 0 0 0.06 13.26 7.12 0 0 0 0 0 0.44 39.05 988.9 1015 0 0 0.01 3 0 0 0 0.01 0 0.99 0.01 0 0 0 0.14 3.48 7.79 5.93 1065 42.25 2.81 0.37 4 0 0 0 0 0.24 0 0.02 0 0 0 0 0 0.19 94.67 3.41 14.02 2.65 0.31 5 0 0 0 0 3.92 0.23 0.46 0.01 0 0 0 0 3.24 420.1 36.31 89.64 23.48 4.73 6 0000000000.4411.340008.8448.069.180 7 000.010.0500000 01.24.35002.240.4500 8 00.030.110.090.0500002.219.4920.369.9828.290000 9 0.010.130.340.180.080000 6.122.1331.1413.0427.270000 Tuvalu Wave Risk Study 13 6 GEMS – Global Environmental Modelling Systems Report 29/04
NE Cyclones( 030 deg)
Pr=950hPa Pr=930hPa
Tide=0.0m (MSL) Track ID Track ID Location123456789 123456789 1 0 0 1.6 126.9 3759 2743 1.95 0.23 0 0 0.01 3.83 355.2 11043 8269 31.58 3.29 0.31 2 0 0 0.14 34.04 2114 1409 0.22 0.02 0 0 0 0.4 118.8 7555 5259 6.06 0.39 0.02 3 0 0.01 3.62 12.81 8.12 1291 31.54 1.2 0.21 0 0.13 20.55 320.2 18.67 4809 124.5 4.89 0.7 4 0 0 0 0.03 287 2.28 36.81 2.34 0.5 0 0 0 0.06 1474 2.55 155 12.77 1.57 5 0 0 0 0.42 803.3 16.24 137.7 13.26 3.82 0 0 0 0.77 3155 19.38 464.4 54.7 9.66 6 0.060.44000013.120.600.391.39000063.043.350 7 0 0.06 0.05 0.51 0 0 0.07 0.02 0 0 0.49 0.7 0 0 0 8.17 0.31 0 8 1.795.597.382.063.76000017.9835.4334.825.449.341.07000 9 1.434.334.171.031.23000012.2226.0113.962.421.520.35000 Tide=0.25m (MSL) 1 0 0.01 3.49 196.5 4671 3551 4.4 0.6 0.02 0 0.03 7.77 509.9 12940 10032 56.36 6.74 0.77 2 0 0 0.34 55.2 2697 1881 0.52 0.04 0 0 0 0.88 177.9 9040 6541 11.39 0.85 0.04 3 0 0.05 7.95 25.69 17.4 1973 60.92 2.89 0.58 0 0.38 39.5 506.5 38.21 6779 218.7 10.54 1.75 4 0 0 0 0.07 388.2 4.23 55.48 4.03 0.94 0 0 0 0.14 1848 4.9 217.5 20.06 2.76 5 0 0 0 0.94 1077 30.35 206.7 22.83 7.16 0 0 0 1.65 3922 37.55 648.2 85.71 16.98 6 0.221.3000030.261.7901.183.670000123.58.280 7 0 0.24 0.2 1.55 0 0 0.3 0.08 0 0 1.48 2.03 0 0 0 20.38 1.01 0 8 3.97 11.06 14.3 4.58 8.09 0.01 0 0 0 31.85 58.97 58.08 10.86 18.43 3.69 0 0 0 9 3.8110.2810.012.93.54000026.0451.5729.56.154.321.88000 Tide=0.5m (MSL) 1 0 0.05 7.65 304.2 5802 4595 9.94 1.55 0.06 0 0.11 15.75 731.9 15163 12172 100.6 13.84 1.9 2 0 0 0.79 89.52 3442 2509 1.23 0.12 0 0 0 1.92 266.3 10818 8134 21.39 1.84 0.12 3 0 0.17 17.46 51.51 37.28 3016 117.7 6.95 1.6 0 1.08 75.95 801.1 78.21 9556 384.2 22.73 4.39 4 0 0 0 0.16 525.1 7.88 83.62 6.93 1.77 0 0 0 0.3 2317 9.41 305.3 31.51 4.86 5 0 0 0.01 2.1 1443 56.7 310.4 39.32 13.44 0 0 0 3.55 4874 72.74 904.8 134.3 29.86 6 0.833.87000069.755.303.599.68000024220.460 7 00.890.754.70 0 1.30.350 04.445.840 0 050.833.310 8 8.83 21.89 27.7 10.16 17.4 0.05 0 0 0 56.42 98.15 96.9 21.68 36.38 12.73 0 0 0 9 10.17 24.39 24.03 8.17 10.18 0.02 0 0 0 55.5 102.2 62.36 15.62 12.34 10.01 0 0 0 Tide=0.75m (MSL) 1 0 0.19 16.74 470.9 7209 5947 22.46 4 0.22 0 0.39 31.93 1051 17768 14768 179.6 28.41 4.72 2 0 0.01 1.86 145.2 4392 3347 2.93 0.32 0.01 0 0.02 4.17 398.6 12945 10117 40.18 4.02 0.31 3 0 0.59 38.35 103.3 79.86 4610 227.4 16.75 4.41 0 3.08 146 1267 160.1 13470 674.9 49.01 11 4 0 0 0 0.36 710.3 14.65 126 11.93 3.32 0 0 0 0.63 2904 18.06 428.5 49.51 8.54 5 0 0 0.04 4.7 1934 105.9 466.2 67.71 25.23 0 0 0 7.61 6058 140.9 1263 210.4 52.5 6 3.1111.520000160.815.76010.8925.53000047450.560.03 7 0 3.34 2.9 14.22 0 0 5.68 1.59 0 0 13.35 16.81 0 0 0 126.8 10.78 0 8 19.63 43.34 53.66 22.56 37.42 0.45 0 0 0 99.94 163.4 161.7 43.29 71.79 43.86 0.01 0 0 9 27.12 57.86 57.66 22.99 29.24 0.33 0 0 0 118.3 202.7 131.8 39.68 35.19 53.37 0 0 0 Tide=1.0m (MSL) 1 0 0.71 36.64 729.1 8956 7697 50.71 10.34 0.79 0 1.35 64.74 1508 20821 17918 320.5 58.31 11.69 2 0 0.03 4.37 235.4 5604 4466 6.96 0.89 0.02 0 0.06 9.08 596.6 15490 12582 75.49 8.77 0.85 3 0 2.02 84.25 207.2 171.1 7046 439.2 40.33 12.19 0.01 8.81 280.7 2004 327.7 18987 1186 105.7 27.57 4 0 0 0 0.79 960.7 27.25 190 20.54 6.22 0 0 0 1.36 3640 34.66 601.4 77.78 15.02 5 0 0 0.14 10.48 2592 197.9 700.1 116.6 47.36 0 0 0.02 16.34 7530 273 1763 329.6 92.29 6 11.6434.240000370.846.8033.0467.360000928.6124.90.24 7 0.01 12.53 11.2 43.07 0 0 24.87 7.15 0 0.06 40.11 48.42 0 0 0 316.4 35.14 0 8 43.65 85.81 104 50.06 80.51 4.05 0 0 0 177 271.9 269.7 86.43 141.7 151.2 0.12 0 0 9 72.3 137.3 138.4 64.69 84 5.09 0 0 0 252.1 401.9 278.6 100.8 100.4 284.5 0 0 0
Tuvalu Wave Risk Study 13 7 GEMS – Global Environmental Modelling Systems Report 29/04
ENE Cyclones( 070 deg)
Pr=990hPa Pr=970hPa
Tide=0.0m (MSL) Track ID Track ID Location123456789 123456789 1 0 0 0.3 4.11 13.43 0.86 0 0 0 2.3 19.94 116.9 397.5 625.5 63.99 0.18 0.01 0 2 0 0 0.02 0.54 2.32 0.07 0 0 0 0.25 3.58 31.35 140.8 243 13.83 0.01 0 0 3 000000000 0000.1418.548.290.1500 4 0 0 0 0 0.02 0 0 0 0 0 0.01 0.76 13.61 8.96 4.39 0.61 0.04 0 5 0 0 0 0.06 0.34 0 0 0 0 0.02 0.2 5.89 64.16 47.68 24.72 4.87 0.51 0.02 6 000000000 0000000.0500 7 000000000 000000000 8 000000000 00.050.01000000 9 000000000 00.010000000 Tide=0.25m (MSL) 1 0 0.01 0.77 8.35 24.91 2.05 0 0 0 4.87 35.36 181.4 565.4 869.8 109.3 0.49 0.02 0 2 0 0 0.06 1.17 4.53 0.19 0 0 0 0.57 6.7 50.91 208.3 350.5 24.84 0.03 0 0 3 0 0 0 0 0.01 0.02 0 0 0 0 0 0.01 0.41 37.26 18.56 0.45 0.02 0 4 0 0 0 0.01 0.05 0 0 0 0 0 0.03 1.39 21.27 14.42 7.61 1.15 0.08 0 5 0 0 0 0.16 0.77 0.01 0.01 0 0 0.06 0.47 10.71 99.24 75.89 42.94 9.14 1.09 0.05 6 000000000 0000000.2200 7 000000000 000000000 8 000000000 00.170.060.0100000 9 000000000 00.060.01000000 Tide=0.5m (MSL) 1 0 0.03 1.96 16.97 46.19 4.93 0.01 0 0 10.35 62.71 281.5 804.3 1210 186.6 1.37 0.07 0 2 0 0 0.16 2.51 8.84 0.48 0 0 0 1.29 12.53 82.66 308 505.7 44.64 0.1 0 0 3 0 0 0 0 0.03 0.08 0 0 0 0 0 0.02 1.21 74.85 41.55 1.33 0.06 0 4 0 0 0 0.02 0.12 0 0 0 0 0.01 0.07 2.54 33.23 23.22 13.19 2.15 0.18 0.01 5 0 0 0 0.4 1.72 0.02 0.03 0.01 0 0.16 1.09 19.5 153.5 120.8 74.62 17.15 2.34 0.15 6 000000000 0000000.9200 7 000000000 000000000 8 0000000000.010.560.210.0600000 9 0000000000.010.270.040.0100000 Tide=0.75m (MSL) 1 0 0.12 4.97 34.48 85.65 11.85 0.03 0 0 21.99 111.2 436.6 1144 1682 318.8 3.79 0.26 0 2 0 0 0.44 5.38 17.23 1.22 0 0 0 2.92 23.45 134.2 455.4 729.4 80.21 0.28 0.01 0 3 0 0 0 0 0.12 0.31 0 0 0 0 0 0.09 3.51 150.4 93.03 3.92 0.24 0.01 4 0 0 0 0.05 0.26 0 0 0 0 0.02 0.16 4.65 51.91 37.38 22.85 4.05 0.39 0.01 5 0 0 0 1.01 3.85 0.08 0.11 0.03 0 0.44 2.52 35.48 237.4 192.3 129.6 32.19 5.02 0.41 6 000000000 0000003.890.010 7 000000000 0000000.0100 8 0 0 0.01 0 0 0 0 0 0 0.07 1.83 0.77 0.25 0.01 0 0 0 0 9 00.010.010000000.051.240.220.0500000 Tide=1.0m (MSL) 1 0 0.5 12.6 70.06 158.8 28.45 0.14 0 0 46.69 197.2 677.4 1627 2339 544.4 10.48 0.95 0 2 0 0.02 1.19 11.53 33.6 3.1 0 0 0 6.58 43.86 218 673.5 1052 144.1 0.83 0.04 0 3 0 0 0 0 0.53 1.23 0.01 0 0 0 0.01 0.41 10.24 302.1 208.3 11.58 0.91 0.04 4 0 0 0 0.13 0.58 0.01 0.01 0 0 0.05 0.38 8.52 81.11 60.18 39.6 7.61 0.84 0.04 5 0 0 0.01 2.57 8.62 0.28 0.36 0.11 0.01 1.22 5.83 64.57 367.2 306 225.3 60.42 10.78 1.11 6 000000000 00000016.510.120 7 000000000 0000000.1100 8 0 0 0.06 0 0 0 0 0 0 0.41 5.99 2.91 1.15 0.07 0 0 0 0 9 00.060.090000000.385.621.330.390.010000
Tuvalu Wave Risk Study 13 8 GEMS – Global Environmental Modelling Systems Report 29/04
ENE Cyclones( 070 deg)
Pr=950hPa Pr=930hPa
Tide=0.0m (MSL) Track ID Track ID Location123456789 123456789 1 60.64 251.5 821.1 1909 2572 316.4 13.96 0.19 0.06 297.7 927.7 2434 4930 7245 641.9 129.7 5.84 3.05 2 13.91 79.61 336.4 937 1346 94.9 2.34 0.01 0 97.97 390.5 1250 2913 4595 216.2 34.53 0.8 0.33 3 0 0.01 0.33 9.96 590.3 234.2 5.4 0.07 0 0.04 0.38 6.54 100.9 3147 1587 26.87 0.2 0 4 0.37 4.03 23.6 162.4 38.08 126.1 11.31 0.83 0.1 4.53 30.85 99.16 596.5 169.1 750.9 92.72 14 0.94 5 3.22 23.23 101.5 497.7 160.3 424.3 53.04 6.12 1.12 25.71 125 333.2 1466 549.7 1916 313 63.73 6.77 6 0000001.30.120 00000027.795.740.17 7 0000000.0400 0000001.290.270 8 0.160.180.060.02000000.490.310.030.010.020000 9 0.010.0100000000.030.020000.01000 Tide=0.25m (MSL) 1 98.39 367.2 1109 2447 3285 485.9 26.67 0.51 0.17 428.9 1236 3067 5974 8719 953.3 206.8 11.44 6.25 2 23.72 121.3 470.8 1239 1769 152.6 4.69 0.04 0.01 147.1 539 1622 3622 5661 335.9 57.61 1.67 0.73 3 0 0.04 0.9 20.73 923.6 414.6 12.09 0.2 0 0.12 1.01 14.04 176.2 4413 2469 53.43 0.54 0 4 0.7 6.7 35.81 223.4 57.17 183.4 18.24 1.51 0.21 7.48 45.95 139.7 770.7 235.7 1002 133.8 21.74 1.7 5 6.08 38.29 152.3 677.2 237.8 613.8 85.32 11.07 2.28 42 184.2 464.3 1874 756.7 2538 448.4 98.11 12.11 6 0000004.020.430 00000061.8313.630.57 7 0000000.1900 0000004.280.920.01 8 0.460.50.20.070.0100001.250.840.10.020.060.030.0200 9 0.050.050.010000000.130.07000.010.1000 Tide=0.5m (MSL) 1 159.6 536.1 1497 3136 4196 746.3 50.95 1.34 0.49 617.8 1647 3865 7242 10492 1416 329.8 22.4 12.84 2 40.43 184.7 659 1637 2326 245.3 9.42 0.11 0.02 220.9 743.9 2105 4504 6974 521.8 96.13 3.46 1.6 3 0.01 0.13 2.46 43.15 1445 734 27.08 0.61 0 0.39 2.68 30.14 308.4 6188 3840 106.2 1.48 0 4 1.34 11.14 54.34 307.2 85.83 266.7 29.42 2.75 0.43 12.33 68.45 196.9 995.7 328.5 1337 193 33.77 3.06 5 11.49 63.12 228.7 921.3 352.6 887.8 137.2 20.03 4.65 68.62 271.3 646.8 2397 1042 3362 642.4 151 21.67 6 00000012.421.540.03000000137.532.361.93 7 0000000.940.030 00000014.243.10.04 8 1.33 1.44 0.64 0.25 0.04 0.01 0 0 0 3.22 2.27 0.35 0.1 0.26 0.26 0.14 0 0 9 0.24 0.24 0.07 0.02 0 0.01 0 0 0 0.53 0.31 0.03 0.01 0.05 0.93 0.01 0 0 Tide=0.75m (MSL) 1 259 782.6 2022 4020 5360 1146 97.36 3.55 1.41 890 2195 4869 8780 12626 2103 526 43.88 26.36 2 68.92 281.3 922.4 2164 3057 394.3 18.93 0.3 0.07 331.6 1027 2733 5601 8591 810.6 160.4 7.17 3.52 3 0.04 0.45 6.67 89.81 2261 1299 60.67 1.84 0.01 1.23 7.1 64.73 539.8 8677 5973 211.3 4.07 0 4 2.54 18.53 82.46 422.4 128.9 387.9 47.45 4.99 0.89 20.34 101.9 277.4 1286 457.8 1785 278.4 52.46 5.5 5 21.71 104.1 343.3 1253 522.8 1284 220.7 36.23 9.47 112.1 399.7 901.1 3066 1434 4454 920.3 232.5 38.8 6 00000038.385.530.19000000305.976.836.58 7 0000004.570.20 00000047.3310.490.26 8 3.86 4.13 2.05 0.91 0.2 0.09 0 0 0 8.27 6.14 1.23 0.42 1.05 2.2 0.81 0 0 9 1.11 1.12 0.39 0.12 0.03 0.18 0 0 0 2.19 1.38 0.16 0.08 0.35 8.6 0.15 0 0 Tide=1.0m (MSL) 1 420.2 1142 2730 5152 6847 1760 186 9.41 4.12 1282 2924 6135 10646 15193 3123 838.9 85.94 54.12 2 117.5 428.4 1291 2860 4018 633.8 38.03 0.84 0.22 497.9 1417 3547 6965 10583 1259 267.7 14.87 7.71 3 0.19 1.61 18.12 186.9 3537 2301 135.9 5.57 0.06 3.93 18.8 139 944.9 12167 9289 420.1 11.17 0.01 4 4.82 30.81 125.1 581 193.5 564.2 76.52 9.06 1.81 33.55 151.8 390.9 1662 638.1 2382 401.7 81.49 9.89 5 41.03 171.5 515.4 1705 775.3 1858 355 65.55 19.33 183.1 588.8 1255 3921 1975 5901 1318 357.9 69.47 6 000000118.619.831.18000000680.5182.422.41 7 00000022.231.310.01000000157.335.461.6 8 11.22 11.85 6.6 3.35 1.07 1.18 0.02 0 0 21.27 16.6 4.28 1.74 4.29 18.78 4.66 0.01 0 9 5.18 5.14 2.14 0.8 0.32 3.04 0.04 0 0 9 6.13 1.02 0.58 2.35 79.33 1.88 0 0
Tuvalu Wave Risk Study 13 9 GEMS – Global Environmental Modelling Systems Report 29/04
Tuvalu Wave Risk Study 14 0