Report on Proceedings of a Workshop to Determine Appropriate Map Format, Distribution and Use Guidelines for Storm Surge Maps Prepared for Antigua and Barbuda

Workshop held at Royal Antiguan Hotel, Antigua
1^st and 2^nd December, 1998.

Organization of American States
General Secretariat
Unit for Sustainable Development and Environment

USAID-OAS Caribbean Disaster Mitigation Project
1998

This report was prepared by
Lynette Atwell

Introduction

The Caribbean version of the TAOS ['The Arbiter of Storms'] model, developed by Charles Watson for the Caribbean Disaster Mitigation Project (CDMP) is based in the Caribbean Meteorological Institute (CMI). CMI has begun development of a series of Maximum Envelope of Water (MEOW) maps of Antigua, which will be used as a pilot project for the development of MEOWS for other Eastern Caribbean Islands. The major goal of this project is to develop prototypes for maps of wind and surge hazards from tropical storms. It is expected that these maps will facilitate planning and preparedness activities for disaster and other development planning agencies.

Purpose and Objectives of the Workshop

The purpose of the workshop was to determine appropriate map format, distribution plan and use guidelines for the storm hazard information produced for Antigua.

The objectives of the workshop were:

1. To obtain specific information with reference to the layout, scale and style for the final maps.
2. To determine the Guidelines/information to be distributed with the atlas.
3. To recommend proposals for the coordinated distribution and use of the storm hazard information in Antigua.

Workshop Format

The workshop was designed to do the following:

1. Provide general information with respect to the project, hazard mapping and hurricanes and hurricane forecasting.
2. Provide information about the use of the model for both lay and technical persons.
3. Examine and comment upon the draft maps produced by the project.
4. Obtain feedback from the participants so that they could inform the map preparation exercise.

Duration of and Attendance of the Workshop

The workshop was attended by a total of 21 persons who came from a wide cross section of government agencies, and community groups which deal with disasters, as well as a few persons from professional organisations.

It is interesting to note that all of the participants who attended on Monday returned on Tuesday for the technical session. Lists of persons who attended the workshop on both days are attached at Appendix I and II.

Formal Opening of Workshop

The opening session was chaired by Mr. John De Nully the Coordinator of National Organisation for Disaster Services (NODS) in Antigua. The workshop was opened by Mrs. V. Alexander the Permanent Secretary of the Ministry of Labour and Home Affairs who indicated that given recent experiences there was support, interest and need for initiatives such as the storm surge mapping project. Steven Stichter of the OAS then made a presentation on the Background to the Project indicating that it was a regional project for reducing vulnerability in the Caribbean. He also indicated that the Antigua project was a pilot project which would be used as a basis for development of other maps, atlases in the Eastern Caribbean.

Working Session – Day 1

Maps produced by the project for Antigua were displayed for the duration of the workshop. Since the participants at the workshop came from a number of varied backgrounds it was felt that it was necessary to provide some general information with respect to hazard mapping as a whole, as well as storm surge and hurricane. As a result introductory papers with information for persons with varying levels of understanding of disaster preparedness and mitigation activities were presented at the beginning of the workshop.

Lynette Atwell the workshop facilitator presented an overview of the Use of Hazard Mapping, so that there would be a wider understanding of the hazard mapping process.

This paper outlined the types of hazard mapping and indicated their uses in the elaboration of planning policies, development of standards and management of systems. It also pointed to the role hazard mapping could play in informing the legal and regulatory framework and indicated the range of groups that would use hazard mapping. A copy of the paper is attached at Appendix III.

Mr. S. Burton from the CMI was responsible for the technical presentations on the first day of the workshop. He presented a paper on Tropical Cyclone Forecasting. This paper defined a tropical cyclone, examined forecasting methods, errors, and strike probability forecasts. Outputs from Hurricane Georges were used to demonstrate probability ellipses for Antigua. This paper is attached at Appendix IV.

Discussion

The major issues raised in this session were:

1. That many persons do not understand the information put out by Meteorological Offices
2. That Meteorological data was published without any interpretation which causes problems for both the Meteorological Office as well as the Disaster Agency.

It was suggested that since predictions were not one hundred percent accurate that it was necessary to educate users of information so that they could have a better understanding of the limitations and variables involved in forecasting. It was felt that fora such as this workshop which involved a wide cross section of participants were important in determining how such information was to be used.

It was also suggested that there should be specific programmes designed to expose persons to the use and interpretation of meteorological information.

Presentations the model, its uses and Interpretation and Discussions

Mr. S. Burton of CMI indicated that the TAOS model was a model for assessing storm surge and wind hazards from tropical storms and hurricanes and was developed by C. Watson, and licensed to the OAS. The TAOS/L model was installed at the CMI in 1994 and has been changed and enhanced with the latest version of the model being installed in October 1998. See attached paper at Appendix V

Discussion re: TAOS/L Model Overview and Use

During the discussion the following matters were raised:

1. The relationship between the TAOS/L and the Sea, Land and Overlake Surges from Hurricanes (SLOSH) model. It was explained that the preparation of the SLOSH model database was time-consuming, while the TAOS/L model has a ready-to-use database (at a resolution of approximately 1km grid cells). TAOS/L also contains a a data base of historical storms which can be modeled and produces GIS-compatible results.
2. The question was raised as to what factors were used in determining surge.
   It was pointed out that the wave output from the model corresponds to deep water waves, rather than onshore wave heights. It was further pointed out that wave action was dependent upon the shape of the shore line.
3. The question was raised as to whether site specific information could be provided and if vulnerable sites could be identified for planning purposes through use of this model.
   It was indicated that the smallest area generated by the version of the model in use in this project was 1 km square and this was too large an area to provide site specific information.
4. A query was raised about the generation of information for different areas. It was pointed out that information on storm surge and wind hazard could be generated for any point on the island
5. The question was raised as to whether the TAOS/L model would be available for the use of agencies which required it. Currently, the model will remain housed at CMI.
6. The view was expressed by several participants and more specifically by the head of the NODS that the tools and techniques being used were relevant to the needs of Antigua especially with reference to disaster preparedness and specifically with reference to the preparation of evacuation plans.
7. Some concerns with respect to the scale of the maps were expressed. It was pointed out that the maps on display were small, but they can be enlarged. Although the model can be run at a more detailed level the CMI was limited by the information that could be compiled for a regional data base.
8. It was suggested that this tool was very useful for planning purposes especially with respect to coastal development.
9. The question was raised as to whether there was the technical capability to provide more detailed information on the maps.
   It was pointed out that it was possible, but not in the life of this particular project as more work would be required in the development of detailed data bases.
   It was suggested that it may be possible to pursue the development of more detailed maps for specific cases. This could also be pursued at a later date.
10. The suggestion was made that the model could be used to inform scenario development for disaster preparedness.
    It was suggested that CDERA and the CMI could be responsible for carrying forward work in this area.
11. The representative of the Fisheries Department indicated that they would need more detailed maps for their purposes, although the maps as presently prepared could assist them in the early stages of their planning process.
12. The question was raised as to the form in which the maps would be made available, whether as hard copy or digital form.
    It was stated that the maps could be made available in either form as the digital form could be read in GIS.
13. The question was raised as to whether the system could be used as a forecasting tool and the length of time required for such use.
    It was indicated that once an advisory was made available it was possible to run the model in half an hour in real time, however, the use of the information for forecasting would depend upon how the local disaster agency used the information made available to them.
14. The suggestion was made that with the type of information from the atlas it would be possible to be more stringent about building line set backs.
15. A specific request was made by the representative of the Police Department that the atlas should be made available to them so that they could better inform the public of what is likely to happen in the event of a hurricane.
    It was further suggested that the atlas should provide appropriate explanations so that the information would be understandable.
16. A representative of the Disaster Agency then suggested that they would undertake to make the maps available to anyone who expressed the need for them.
17. There was further discussion about making the maps available to users and it was suggested that a committee comprised of the following agencies be set up to foster and guide the process for making use of the maps:
• The National Office for Disaster Services
• The Fisheries Department
• The Meteorological Department
• The Development Control Authority
18. It was then pointed out that at some stage there would be the need for more detailed information (site specific) in the proposed atlas and the question was raised as to who would carry forward work in this area.
    It was then suggested that the preparation of more detailed maps should be considered as part of a long term proposal. CMI and CDERA in consultations with the users of the information could get together to develop proposals for that purpose.

Day two (2) of the Workshop was meant to be a detailed session for technical officers. All of the participants who attended on the first day were present at this session. Mr. S. Burton provided a background to and brief demonstration of the model. See Appendix V.

He selected for his demonstration the 1979 hurricane David. He indicated that the following information was used:

1. Positions – latitude and longtitude
2. Maximum wind
3. Radius of the Maximum winds

Using the above information the model provides the following outputs for each selected point along a track:

1. Maximum wind speed
2. Peak surge
3. Deepwater wave heights

Mr. Burton indicated that the model can provide quick views of maximum predicted surge for one or more islands

The Maximum Envelope of Water (MEOW) is produced by running the model for multiple storm tracks, spaced at a fixed distance apart, for a selected intensity, speed and direction.

It was pointed out by Mr. Burton that the MEOWS were very useful for disaster planning as they could be prepared beforehand. Once the track and intensity of the tropical cyclone is known, the MEOWs could be used to indicate the maximum surges likely and priority areas which required special attention could be pinpointed.

Discussion

Although the discussions on the second day were of a more technical nature there were a number of areas that participants wished to clarify based upon the first presentations. Much discussion also centred around how people were to be trained and how work on the project would be carried forward. It was also very clear that a great amount of information was provided on the first day and some of the issues raised were because there was now a better understanding of what the model was supposed to do and how it worked.

The following were pertinent questions raised and the issues discussed:

1. Whether the model could address a stationary system.

It was indicated that the model could address such a system .

2. The role of the CMI in the provision of information and maps was discussed. Some of the issues raised were the operation of the CMI during the coming season and whether the storm surge information emanating from the project can be used when meteorological offices were giving advisories.

Mr. Burton indicated that the CMI was of the view that the information provided by them was to be used for guidance, as they did not want any conflicts with the National Hurricane Centre.With respect to the giving out of the storm surge information he further suggested that this information could be used to inform local planning efforts being carried out by the disaster agencies.

3. The comment was made that some participants could not read maps and that it would be necessary to provide information and or have the maps carefully explained. It was pointed out that the maps would be accompanied by interpretive material
4. Mr. S. Stitcher used the display maps and explained how they were to be interpreted. This presentation clarified many issues with respect to the mapping. Comments were made about the visual impact of the maps and it was indicated that the colours should be graduated if the map presentation have any meaning for the viewer.

It was also pointed out that an explanatory document would accompany the maps

5. The level of resolution of the maps was raised again at this session and the view was expressed that a higher level of resolution was needed so that areas could be distinguished, in order to inform the planning process.
6. The question was raised about the life of the project. Participants wished to know if this was the end of the project or would further work be carried out to produce more refined information
7. It was pointed out that the material on the maps would need to be interpreted for the general public. The interpretation of the maps was the responsibility of the National Office for Disaster Services which has responsibility for dissemination of information about disasters.
8. The matter of a topographical base for the maps was raised as it was felt that there would be the need to know how the surge heights would impact land. It was therefore recommended that the maps should have a topographical base.
9. The question was raised as to the use of the software. CMI will continue to be the home for TAOS in the region.
10. A number of training issues were raised, these were:

1. Whether there would any follow up activity such as a training fora for Disaster Coordinators in order to acquaint them with the system.
2. Whether consideration could be given to a train the trainers programme in the use of the maps

Summary of Major Recommendations

1. Guidelines for Map Preparation

A. Map Layout and Design Information

The following information should be included on the maps being prepared:

1. Topography
2. Roads

Map Presentation: the colours on the maps should be graduated in such a manner that different zones can be easily recognized.

B. Information which will accompany the Maps

The information provided on the maps should be simple and easy to understand as the maps will be used by persons with varying technical capabilities.

C. Map Distribution

It was agreed that the distribution of the maps should be properly coordinated.

D Administration with reference to use of Atlas/Maps

It was recommended that a committee be set up to:

1. to promulgate the use of the maps.
2. To train persons to use the maps.

The membership of the committee should be drawn from the following agencies:

• The National Office for Disaster Services
• The Fisheries Department
• The Development Control Authority
• The Meteorological Department

E. Training

It was recommended that consideration be given to holding train the trainers workshops in the use of the maps.

F. Long Term Proposals

1. It was recommended that model should be used for scenario development and that the CMI and CDERA could develop proposals for this.
2. It was agreed that a higher level of resolution would better inform the site specific requirements of the physical planning agencies.

G. Request for maps atlases

The following agencies indicated their interest in receiving maps/atlases:

• The National Office for Disaster Services
• The Development Control Authority
• The Fisheries Department
• The Police Department
• The Meteorological Department

Appendix I: List of Participants, December 01, 1998

Appendix II: List of Participants, December 02, 1998

Appendix III: The Use of Hazard Mapping

Introduction

The purpose of this presentation is to provide a background to the entire hazard mapping process so that there can be a full understanding of the requirements not only for emergency management but also how mitigative action can inform the development process

Before considering the various types of hazard mapping if we examine the Disaster Cycle it can be determined where hazard mapping falls. In the cycle, it falls in all of the pre planning stages namely National Development, Prevention, Mitigation and Preparedness.

The following are the types of hazard mapping:

Types of Hazard Mapping

1. Flood Plain

This involves the production and generation of hydrological information, hydrological analysis which involves an examination of flood flow frequency, magnitude of peak flows etc. The end product is a map indicating areas likely to be flooded.

2. Storm Surge

This will indicate timing, severity and sequence of surge activity.

3. Wind

The timing and severity of wind activity.

4. Landslide

Maps which indicate areas prone to land slips. These maps are based upon geomorphic, geologic, and topographic conditions and may use hydrological information

5. Earthquake – Volcanic

Maps which identify areas with these activities as well as zones indicating the intensity of activity.

6. Technological

Maps which

1. identify areas likely to be impacted by an event
2. The extent of an impact in the event of an accident

The Use of Hazard Mapping

Hazard mapping is used to inform all planning processes, the development of standards, management systems and legal and regulatory mechanisms.

Hazards in Development Planning

One hazard can affect a country’s development strategy as it can impact on the type and location of investment projects as well as infrastructure. It is therefore crucial that hazards be taken into account in planning at any level.

Hazard mapping is the tool which provides information which can be used to

• Identify potential hazard areas and situations
• Assist in the elaboration of land use policies
• Inform combination of land uses
• Determine the location of investment projects and infrastructural development
• Assist in the avoidance of hazards
• Inform policies for the protection of the environment

Standards

When projects are to be implemented, hazard mapping can aid developers and development agencies in the elaboration of standards for development. Development of the standards will in turn inform building regulations and practice.

The following are the areas which hazard mapping can inform:

1. The development of design standards:

• Set backs
• Building heights
• Lot sizes
• Density of development

2. Development of protective works

• Structural
• Non Structural

Management

Hazard mapping is a tool which can be used to inform managers of the type of action which can be taken in the likelihood of an event, because it can provide information about areas likely to be affected by an event

The following are the activities which hazard mapping can inform:

Emergency Management - The preparation of plans for an emergency including warnings and evacuation plans

Protective Measures - It can aid in the determination and selection of protective measures for both the community as well as for buildings/facilities

Training and Education - It can aid in the development of training plans as the emergency managers will know before hand which areas/sites/buildings are vulnerable.

The Legal and Regulatory Framework

Because hazard mapping can be used to inform development of standards as well as building practice it can provide information for the development of the legal and regulatory framework for building and land development.

This legal and regulatory framework will in turn indicate how inspection of buildings and development of land is carried out.

Advice to Private Agencies

Hazard mapping can advise private agencies of the risks they may need to take. The insurance industry and mortgage financing institutions can benefit from information provided by hazard information which can assist in the development of their policies so that they can determine what risks they are likely to encounter.

The Participants in Hazard Mapping Process

There are a number of participants in the hazard mapping process these are: 

1. The persons who produce the maps
2. The users of the maps

In many instances there is an overlapping of roles, in that some of the users assist in the production of the maps.

The following are the major participants in the hazard mapping process:

a) The Producers of Hazard Maps

• Research and Technology Institutions (UWI, CMI etc.)
• Land Use Planning Agencies, Survey Departments, Drainage Departments etc.

b) The Users of Hazard Mapping

A: Government and Other Development Agencies

• The Planning Agencies – Social, Economic and Physical
• The Disaster Agency
• The Developmental Agencies – Works Departments, Land Development Companies, Housing Agencies

B: Other Users

• Architects and Engineers
• The General Public
• Aid Groups
• Insurance and Mortgage Companies

The above is meant to be a broad overview of how hazard mapping can be used in a positive way to enhance and inform development