Beach Erosion; A Vulnerable scenario in the Maldives
26 Geographical atolls with over 1190 Islands, Maldives is situated in the in Indian Ocean, at the heart of the equator. These islands famous for its tourism are indeed in peril. Vulnerable to the huge waves, the low lying states are barely above mean sea level facing threatening consequences for its very existence. These islands face grave danger of beach erosion and land loss. The country with its ever increasing population of over 300,000, distributes itself into 198 inhabited islands. Over 100 islands are used as tourist resort and the remaining are uninhabited. Some of these islands are used as airports and for agricultural purpose. The geographical setups of these islands make them unique and dynamic. Every island has its own unique beach. The size and shape of this current pattern in accordance to the seasonal conditions the islands have directional shifts within the shoreline.
Beaches are areas of continuous change, where natural forces of wind and water interact with land. Beach is the area between the low tide level and that reached by the high tide levels and storm waves. It is made up of deposited material which usually builds up on the wave cut plate form where the sea is shallow. All of the Maldivian islands are made up of coral reef and coral sand. The islands are entirely built and sustained by the continuous ecological and physical process in the coral reef ecosystem of which the existence of islands depends lately upon the wave action on the shore its beaches islands found in the Maldives vary in shape from small sand banks with sparse vegetation in the centers to elongated strips and also to relatively circular islands with a large cover of vegetation It is therefore completely natural for beaches to change. Yet again it is the force of nature at its work. These natural forces include wind waves current, tides and also extreme events such as storms and tsunamis.
One the other hand, Maldivian beaches change as a result of its different monsoons. It is during the south west monsoon the waves come from the west and south west, thus the sand are moved so that in many cases it is built up on the eastern side of the islands. During then north east monsoon the reverse happens with the waves and the current coming from the north east and the sand build up on the western side of the island. However, it is definitely not only the natural forces that change beaches, its shape and sizes. Humans as we call ourselves are another threat for the beaches, human activities such as sand and coral miming, trampling on the coral reef, building harbors and jetties and dredging and reclamation influences the beach.
How does beach erode?
To understand beach erosion, it is necessary for us to understand ‘waves’. Waves are the vital energy input of the coastal system. Waves are largely caused by the wind. Their size and strength are directly conditioned by certain characteristics. Namely; wind speed, wind persistence. The length of time, wind of particular strength and direction has prevailed, the fetch, the distance of open water over which the wind has blown. The longer the fetch – the greater wave size and strength. There are two types of waves: free waves; starts somewhere in the middle of the ocean and move forward under their own momentum forced waves which are driven on shore by the wind. They have shorter wave lengths. A large amplitude and break with greater frequencies as waves break on to the beach the broken wave’s rushes up the beach. This is known as swash. Whereas the return flow running back down the beach under the influence of gravity is called the backwash.
Again there are two types of forced waves. Constructive waves, they have longer periodicity between wave arrival, and they tend to be flatter in wave form and emphasize the swash action. For this reason, they tend to lead a net transport of sediments up the beach. Destructive waves – frequently of steeper form, they arrive at much closer intervals (a period of three to six seconds) and destruct the backwash action of the previous wave. This results in a turbulence ‘coming –down’ beach material – that is an overall erosive effect. Beach erosion takes place when the beach and the land behind the beach are worn away by the reactions of the waves and a new coastline is established further inland.
Why beach erosion in Maldives.
People in Maldives used to build their homes from the coral stones. These coral stones are easily available for them in the surrounding seas. Sand had been taken for building and construction. All of these leading to the trampling on our coral reef. Our reefs play a very vital role as a defense against the strong waves that break into the beaches. The reef slows down its force therefore the swash is not as destructive as it would have been. Human activities that influenced the beach include building harbors and jetties also dredging and reclamation, unplanned construction of jetties and reclamation without proper environment impact assessment leads to devastating results. Cleaning vegetation on the beachside and construction of building near the beach leads the soil to become loose. This again leads to beach erosion. In the Maldives, only a few islands remain protected from beach erosion. Most islands in the country face extreme beach erosion. In some islands the destructive waves break in to resident houses near the beach.
What can be done to reduce beach erosion?
There are several actions that we can make to reduce beach erosion. To cope with beach erosion it is very important that we stop trampling our coral reefs. Our natural defense, we need to stop coral mining. It is important that proper environment impact assessment reports are to be made before the construction of harbor and jetties dredging or reclamation. Leaving a wide band of vegetation between buildings and the beach is an effective way of coping with beach erosion. New buildings should be built a ‘safe’ distance from the dynamic beach zone this not only helps to conserve the beach but also the building. Relocating buildings in danger of collapsing to new locations further in land can be an effective way to cope with beach erosion. Building sea wall can reduce the force of waves. Sea walls are massive structures made of steel. Rock or concrete designed to protect land or buildings from the impact of waves. In Maldives we find sea walls often build in a vertical seaward face. When the wall gets hit by the waves sometimes it reflects back into the next wave, causing more turbulence. It should be noted that sea walls strengthen the edge of the lands and hold it in place for a few years. Male’ was protected by a sea wall in 1992 at a cost of $48 million. The wall was made of dolos (open inter locking form). Water mixture is then pumped via a floating pipe line ion to the beach. However dredging causes a great deal of turbidity and siltation. This can damage coral reefs and sea grass beds. It’s important to take special measures to protect these important ecosystems.
Beach erosion is a very serious issue for the Maldivian islands. The countries economy depends on the gain from the travel and tourism industry. The tourism industry brings all most all of the capital for the country. The islands depend on tourism as the main source of development .What attracts tourists to Maldives are the clear white sandy beaches, blue lagoons and it’s under water coral gardens. Maldives need to protect its vulnerable and dynamic beaches for its own very existence. Today the government has implemented strict laws protecting its beaches. Measures taken include banning of coral mining and conducting regular awareness program explaining the vulnerability of the beaches. beaches has always played a vital role in the everyday lives of the local in the islands . Beaches are associated with moments and memories for local residents. It is therefore a responsibility of each island community to play its part in the protection of these dynamic beaches.
—— REFERENCE: > ‘Environment and people ‘1995 ISBN: 0948721207 > ‘Beach watch: managing our beaches – live and learn environmental education and MEEW 2009 ISBN 99915-95-07-5B > First national communication of the rep of Maldives to the UNFCCC.MEEW 2001 ISBN 99915-828-3-5