ECLAC Disaster ECLAC Disaster Assessment Assessment Training

Manual

Section V (ii) Coastal Engineering:

Reconstruction – Management and Mitigation

ObjectivesObjectives

    To familiarize the assessor with the process that should be followed in organizing any reconstruction efforts.

·    To emphasize the importance of accessing a proper data base during the reconstruction process, and of using appropriate design criteria.

·    To outline the necessity for post construction efforts, which should include proper monitoring and maintenance.

Management RequirementManagement Requirement 1 1[Understanding the cause of the disaster][Understanding the cause of the disaster]

Knowledge of the National Hurricane Centre database of storms, which dates back to 1876 (http://www.nhc.noaa.gov/); rainfall records;

Proper hindcasting of hurricane waves from a knowledge of the hurricane wind field;

Transformation of the hurricane wave climate from deep water to the nearshore zones;

Extremal analysis of the hindcast wave climate or rainfall records, so that design conditions can be extracted. [What return period should be used for design? 50 year or 100 year]

Management RequirementManagement Requirement 1 1[Understanding the cause of the disaster][Understanding the cause of the disaster]

What part does climate change play, if any, in the development of a design criterion?

Management Requirement 2Management Requirement 2[What can be affected by the disaster[What can be affected by the disaster]]

This requires proper mapping of the coastal/river infrastructure, which in turn calls for knowledge of the following:

Locations, physical extents and condition of coastal and river infrastructure;

Extent of coastal communities, population, location of critical infrastructure, degree of vulnerability;

Representation of this data on digital mapping is desirable, or at the very least, on 1:2500 scale mapping;

Definition of coastal infrastructure such as roads, etc.

Grande Anse Bay, Grenada

Dominica

Management Requirement 3:Management Requirement 3:[How damages are effected][How damages are effected]

Requires a sound knowledge of the processes that can result in damage to coastal/river infrastructure and shorelines. These include:

Beach characteristics, seabed bathymetry and sediment processes;

Benthic substrates in the relevant nearshore areas; Nearshore wave climates for design and perhaps day-to-day

conditions; Tidal fluctuations, global sea level rise and storm surge

estimates; Effect of existing and proposed sea defences on shoreline

processes; and River hydrology/hydaulics

Mitigation Strategy & Data Mitigation Strategy & Data RequirementsRequirements

[Implementing protection against diasters][Implementing protection against diasters]

Design and construction of coastal defence or river training works. Data requirements include:

Topographic & bathymetric survey (admiralty charts); Preliminary engineering design of shore protection or

river training works (concept development, site understanding, recommended options);

Preliminary costing of works (examples from similar works);

Mitigation Strategy & Data Mitigation Strategy & Data RequirementsRequirements

[Implementing protection against diasters][Implementing protection against diasters] EIA for proposed works (develop terms of reference

approved by regulatory agencies); Modification of Preliminary Design to accommodate EIA

findings, and presentation of results; Selection of the preferred option; Final design of works (must be designed to withstand

impacts). Preparation of the contract doicuments; The tender process; and Construction of the works.

Protection against disasters can also take the form of building setbacks, emergency relief planning, improvements to the building code, or preperation of a CZMP. This process requires:

A sound knowledge of the areas most at risk (socio-economic data);

Knowledge of the population and infrastructure within the risk area (vulnerability assessment);

Identification of safe shelters (emergency response planning requires that shelters be accessible during hurricane conditions);

2-Tonne boulder in lobby of Trident Hotel – a good case for set-back limits?

Protection further includes:Protection further includes:

A proper evacuation plan (disaster management planning);

Improvements to the building codes (required for CUBIC);

Development of a CZMP, which can be used as a vulnerability reduction tool.

Mitigation Strategies (cont’d)Mitigation Strategies (cont’d)[Ensuring longevity of defence investment][Ensuring longevity of defence investment]

This requires proper maintenance of coastal/river defence works/. Issues to be considered here include:

Monitoring of shoreline movement or change on a regular basis (beach profile monitoring on a regular basis);

Evaluation of effectiveness of sea defence or river training works;

Estimation of residual life left in structure or works; and of the need to do repairs to works;

Evaluation of long-term impacts, if any, on the adjacent shoreline, and the need to modify works to minimise any identified impacts.

Negril after Hurricane Mitch

Self AssessmentSelf Assessment

By this stage you should be able to evaluate the necessary steps required to evaluate, design, implement and monitor the reconstruction works that would be needed following a disaster.