shaik umme salma AEM- MFK -1710 COLLEGE OF FISHERIES MANGLORE

1. COASTAL EROSION AND CONTROL
MEASURES
shaik umme salma
MFK-1710
AEM,CoF,Mangalore

2. CURRENT SCENARIO
• Coastal Length of India - 8129 km
9 maritime states
2 union territories
73 coastal districts
77 cities and towns
• Mumbai, Chennai, Visakhapatnam , Kochi and Kolkata
17 % world’s population live in India. (source: 2013 census)
- ¼ live with in 50 kms of coast line

3. • Mega-diversity country
• 60% of the global population dwelling
• Harbour a variety of ecosystems - Mangroves,
- Coral reefs,
- Seagrass beds,
- Mudflats
- Sandy shores

4. Coastal Erosion
Coastal erosion is the wearing away of land and the removal
of beach or dune sediments by wave action, tidal currents,
wave currents, drainage or high winds.
Erosion by waves Erosion by drainage Erosion by winds

6. COASTAL HAZARDS
sea water
intrusion
shoreline
change
coral
bleaching
soil erosion

9. Structural Non structural
Approach
o Construction of physical
structures.
 Sea walls.
 Groins.
 Jetties.
 Bulkheads
 Revetments.
 Sand dunes
 Growing vegetation around
them.
 Artificial beach Nourishment.

10. Anthropogenic processes of coastal erosion

12. Impacts of Coastal Erosion
1. Loss of habitat/ beach and landscape quality
2. Loss of buildings, infrastructure facilities such as roads and power lines.

13. 3. Degradation of coral reefs due to deposition of silt.
4. Increased turbidity of water.
5. Reduce the tolerance to face natural hazards such as Tsunamis

15. 6. Reduce the sand volume to compensate the natural littoral processes
7. Reduce scenic beauty of the beach.
8. Collapse the tourism in the area.

16. 9. Loss of boat anchorage sites
10. Increase the frequency offloading in the lowland areas.
11. Increase the wave energy on beaches endangering local people.

17. 12. Reduction of coral reef sites.
13. Decrease water quality
14. Marine and associated ecosystems are made more fragile
15. Reduce primary production and fish productivity.
16. considerable annual expenditure for damage mitigation, control and disaster
relief.

18. Prevention/Control of coastal erosion
Three globally adopted erosion prevention/Control strategies;
1. Soft erosion control methods
2. Hard erosion control methods
3. Monitoring only method

19. Soft erosion control methods (Soft stabilization)
• Soft erosion strategies refer to temporary options of slowing
the effects of erosion
Eg;
1. Beach Replenishment
2. Sand dune Management

20. • This is one of the most popular soft engineering techniques of coastal
defense management schemes.
• This involves importing sand off the beach and piling it on top of the
existing sand
1. Beach replenishment

21. 2. Sand dune Management
Sand dune stabilisation or sand dune management works using a number
of different methods in order to prevent the loss of sediment on the beach.
Eg;
1. Introduction of public amenities such as car parks, footpaths, Dutch
ladders and broad walks, to stop the removal of sediment by humans.

22. 2. Education of visitors with noticeboards, leaflets and beach
wardens explain to visitors how to avoid damaging the area.
3. Construct fences using simple materials such as wood, sand
traps to create blowouts.

23. 4. Promoting dune vegetation to prevent sand loss. Also, areas of the beach
can be simply closed to the public to allow rejuvenation to occur.

24. 2. Hard erosion control methods (Hard stabilization).
1. Construction of Groynes
Groynes are barriers or walls perpendicular to the sea, often made
ofconcrete, rock or wood.
Groynes are extremely cost-effective coastal defense measures, requiring
little maintenance

25. 2.Construction of Sea walls
• Walls of concrete or rock, built at the base of a cliff or at the back of a
beach.
• Essentially, a seawall acts as a layer between the vulnerable coastline
and the ocean. Wave action can beat at the seawall without eroding
the coast, although the seawall itself will eventually break down and
require repair or replacement

26. 3. Construction of Revetments
• Revetments are slanted orupright wooden blockade structures built
parallel to the sea on the coast in such a way as to absorb the energy of
incoming water.

27. Use of rock armour
• Large rocks are piled or placed at the foot of dunes or cliffs, which
are placed with native stones of the beach: —
known as rip rap, rubble or shot rock.
• When rock is placed on the beach it is arranged so that large void
spaces are left.
• When waves hit the rock they are only partially reflected, and can
flow round the rocks, expending their energy less quickly which
reduces scour.

28. Construction of Gabions
• Boulders and rocks are wired into mesh cages and usually placed in front
of areas vulnerable to heavy to moderate erosion.
• Gabions are relatively cheap and easy to construct but they are not
suitable for use in locations exposed to wave action because they are too
flexible and are easily destroyed.

29. Construction of offshore breakwaters
• Breakwaters are structures constructed on coasts as part of coastal defense or to
protect an anchorage from the effects of weather and long shore drift.
• Offshore breakwaters, also called bulkheads, reduce the intensity of wave action
in inshore waters and thereby reduce coastal erosion.
• They are constructed some distance away from the coast or built with one end
linked to the coast.

30. Construction of Floodgates
• Floodgates or Storm surge barriers were introduced after the North Sea Flood of
1953 and are a prophylactic method to prevent damage from storm surges or any
other type of natural disaster that could harm the area they "protect".
• They are habitually open and allow free passage, but close when the land is under
threat of a storm surge.
• The Thames Barrier is an example of such a structure.

31. COASTAL EROSION MANAGEMENT: INITIATIVES BY GOVT. OF
INDIA
In order to assist maritime States/UTs in protection of vulnerable coastal areas from sea
erosion, there are two schemes namely
(i) Centrally Sponsored Scheme (transferred to State Sector since April 2005)
(ii) National Coastal Protection Project (NCPP) for protection of coastal areas of
maritime States/UTs from sea erosion
I. Centrally sponsored scheme (CSS)
II. National coastal protection project (NCPP)

32. III. Coastal protection & development advisory committee (CPDAC)
IV. Technical assistance (TA) program financed by Asian Development Bank
(ADB)
V. Preparation of execution manual
VI. Updating of design manual
VII. Exploration of soft structural measures
VIII. Preparation of coastal atlas
IX. Proposals for XI five year plan

33. Conclusion
• Devastatingly negative impact on the life.
• land lost and habitats destruction
• Effect on the economy of the area and the nation.
• If it is not ?- lose precious habitat or worse, our heritage.
• Management approach-mandatory