I. The Behaviour of Tsunami

1. Where the land projects into the sea the effect of tsunami is less.

2.Where the sea caves into the land the attack on people and property had been severe.

3. Where the habitat is located on the “theri” or beyond towards the land the buildings are least affected.

4. Where buildings are constructed removing the “theri” or in-between the “theri” and sea the devastation had been complete.

5. Wherever the low lying area created either by road or street or a stream leading to the sea exists, tsunami has entered inland through it .

6. River mouths have acted as cushions, where unobstructed and played havoc where they were obstructed.

7. River mouths protected by “theri” with covering of creeper kadambu, thazhai, and coconut trees preventing wind and water erosion have passed the energy of tsunami upsteam the river without affecting the banks of reasonable height. Pantivoikkal Odai in Kanyakumari District is an example.

8. In-between groynes sand has deposited to their entire length.

9.Theri covered by creeper Kadambu has stood like a rock fortruss against tsunami.

10. Coconut trees and casuarina have mitigateted the force of tsunami but the plain surface left after harvesting of casuarina trees has acted like a stream to receive tsunami inland.

11. Gaps left in sea walls have acted as jets letting aronomous energy carried by tsunami on habitats.

12. Catamarans, and boats left free on the shore have become powerful missiles in the merciless hands of tsunami in the destruction of human lives and property.

13. The direction of tsunami has not been uniform in adjusent places. There are incidents where in the same village tsunami has attacked from different directions, e.g. Pallam of Kanyakumari District.

14. The level to which the wave raised and level of retreat of water were different in different places.

15. The time gap between successive waves vary from 10 minutes in some places up to 2 hours in some other places.

These aspects regarding the behavior of tsunami are to be studied carefully in detail and a questionnaire prepared for that purpose.

II. Protective Measures:

1. Theri

a. Theri is a natural phenomenon throughout the sea shore. It should be restored wherever disturbed and be maintained properly.

b. The creeper kadambu and the creeper grass with needle pointed leaves are to be grown on theri to arrest erosion.

c. Plantation of sweet scented screw pine (thazhai) will also be useful in conservation of theri.

d. A 4 lane road on top of theri will enhance the usefulness of theri by serving the interest of tourism, sea shore communication and as an indirect compulsion for the proper maintenance of theri.

e. Coconut trees can be planted on both the slopes of the theri. This will also be inducive to and bear part of the cost of the proper maintenance of theri by their regular yield.

f. Plain land between theri and the inland navigation channel is to be used for growing timber wood.

2. Inland Navigation Channel:

a. A.V.M. Channel from Kanyakumari to Kochi has become mostly defunct within the limits of Tamil Nadu.

b. Buckingham Canal from Visahappattinam to Nahappatinam has mostly disappeared south of Chennai. Traceable near Mamallapuram and on both the sides of Kollidam River at its confluence at Pazhayarrai of Cuddalore District.

c. In Kottilpadu of Kanyakumari District the existing length of channel acted as a tomb of the people who lived between the sea shore and the channel. People carried by the tsunami were dumped into the ditch and burried them with the debris carried by it.

d.In Pazhayarrai, the channel, which is well beyond the habitat on to the land, have stopped the tsunami water from entering into the paddy fields by its land ward bank.

e. People of Kottilpadu want to restore the channel for its fresh water and its function as a barrier in preventing sea water displacing ground water. Pazhayarrai people also want to restore the channel.

f. These channels must be restored and new channel excavated between Nahappattinam and Kanyakumari with enough width and depth to carry on navigation even at low tide level.

g. The channel can direct the force of any future tsunami along its course and mitigate its force towards the land.

h. It will provide cheap transport of perishable cargo for short distances and non-perishable cargo for distant places.

i. Rainwater from catchments not intercepted by streams discharging directly into sea through estuaries, can be drained into this channel.

j. Flood discharge from such catchments can be allowed into the channel through lagoons formed in naturally low lying areas or artificially created ones.

3.River Mouths:

a. River mouths can be strengthened with theri protected by plantation of kadambu, thazhai, coconut and other palmeceous plants.

b. The river mouths can be developed into fishing cum transport harbors.

c. If adjacent river mouths are far apart tiny fishing harbours can be built in- between

d. Harbours should have dormitory for fishing people, cloak room for fishing tools, boat service yards, fish sorting and packing places, nets and hooks service yards, net drying yards, fish drying yards, cold storage, canteen, recreation hall, medical centre, training centre connected with fishing and navigation, library and reading room, weather observatory, signal etc., disaster warning centre, disaster shelter etc,

4. Shore line training works

a. Shore, where it caves into the land can be straightened by construction of groyens either perpendicular or inclained according to the site conditions.

b. Wooden groyens are recommended to protect our ecological balance from indiscriminate quarrying of mountains and rivers. The required timber can be obtained by plantations in the plain land between theri and inland navigation channel and the waste areas left waste in our country.

5. Sea Channel

There is a tradition that a sea channel runs south of the cape of Kanyakumari which served navigation purposes. People call it “Kappalodai” meaning “ship stream”. The excavation of such a channel wherever necessary so that navigation from one end of be sea shore of India to the other end is essential. If such a channel be excavated, it along with the theri and the navigation channel will divert most of the energy carried by any future tsunami before it reaches the places were people live. In addition it is important for cheap transport and National defence purposes.

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