Galle city is located at Southern coastal zone of Sri Lanka which the level is almost same and below the sea level. Therefore the city is under a threat of flooding.
In 2004 Sri Lanka had to face a fatal incident called 'Tsunami' which the Sri Lankans had never experienced not even heard. Galle city is the most affected city due to the topography and the 'Galle Fort' (the huge structure adjoining to the sea) which pressurized the sea tides. The tide was more than 5m high which drowned the entire city within few seconds. Hundreds of people and vehicles were drawn to the sea and even a single piece of could not be found yet. The property damages were not accountable.
Since the 2004 Tsunami was the first experience for the Sri Lankans, they could not avoid or survive. But after further studies we realized how to cater such an incident. Generally Tsunami waves occur by sudden movements of two earth plains which provide a huge energy to the sea waves. According to the coastal engineering science, the Tsunami is silent at the deep sea but conveying the generated and dissipated energy towards the coast. As the sea depth reduces, the Tsunami tide tends to go up and release the energy causing disaster to the surroundings.
Considering the nature of this risk, it cannot be avoided but can be mitigated. Precautions should be made to create energy loss at the deep sea and to resist the tide at the coast. Specially designed offshore breakwaters should be applied at the deep sea to dissipate energy at the sea it self.
A thick vegetation should be done at the coast to dissipate energy of the tide as it enters the country.
Sri Lankan government has established a 100m buffer zone from the sea for the construction of building . In addition the buildings at the coastal zone should be specially designed such that the safety factor resists for the Tsunami tides too.
Since Sri Lanka is a developing country, strengthening the resilience is not much appreciable. Therefore the measures for risk mitigation should be implemented.
By Tsunami risk reduction proposals, the community should get a more safe life which secure their properties and habitats. In the economic point of view, the government's expenses of rehabilitation after Tsunami should be minimized after this proposal.Environmental impact should be minimized by Tsunami risk reduction measures.
The evaluation of the proposal can be done after a Tsunami. But can be analyzed by running a model. The strength of the Tsunami tide is normally measured by Richter scale and inundation can be accounted by area and height. But in the practical situation, the indicators should be statistical field data of Tsunami victims.
Verification can be achieved by council approval records on proposals, and implementation, payments etc. In addition the realistic situation can be ensured on field surveys.
From January 2015 to December 2016
Dr Kumara Dhammika Maha Muhandiramge
Senior Municipal Councillor, Galle municipal Council