What is Happening and What is Being Done
BY Thameenah Razeek
Diverse and complex natural processes are constantly modifying coastal-physically, chemically, and biologically at scales ranging from microscopic to global. The diverse interactions and relative importance of these natural processes are influenced by regional and local shoreline characteristics.
Human activity adds a new dimension to coastal change by directly and indirectly modifying and affecting coastal habitats and natural change processes. The study of coastal dynamics can quantify these changes and improve our ability to predict how the shoreline will respond to human activity.
However, as a result of combined landward and seaward action, the Colombo District shoreline's erosion percentage has risen from 20-25 per cent in 2000 to 35.86 per cent in 2019, impacting the District's 24.3-km-long coastline. This was validated by an Asian Development Bank Institute (ADBI) report published on 15 April 2021.
The study examined the consequences of coastal erosion along a contiguous beachfront that stretched through both the Western and North-Western Provinces for a period of 15 years, beginning in 2005 and ending in 2019. A month after this article was released, the MV X-Press Pearl Container Carrier sank.
The MV X-Press Pearl Container Carrier was transporting chemicals when it collapsed off Sri Lanka's western coast in May 2021.Not only the report, but many professionals and activists believe that collaborative approaches to coastal management are vital, particularly in Western Province.
Definition of the Coastal Zone
A Coastal Zone is defined as an area within 300m landwards of the Mean High-Water line and 2 km seawards of the Mean LowWater line, as well as rivers, streams, lagoons, or any other body of water permanently or intermittently connected to the sea, by the Coastal Conservation and Coastal Resources Management Department (CC&CRMD).
This also includes the landward boundary, which shall extend to a maximum of 2 km measured perpendicular to the straight base line drawn between the natural entrance points thereof, and shall include the waters of such rivers, streams, lagoons, or other bodies of water so connected to the sea, as well as the area lying within a further extended limit of one hundred metres inland.
What is causing this to happen to the Shoreline?
Despite the fact that much has been done in recent decades to prevent coastal erosion, it remains a problem throughout the country. Various human activities, in addition to natural erosion sources such as storm surges and fluctuations in wave velocity and river sediment, increase the process.
Mining for river sand reduces the amount of sand reaching the coastline, and building along the shoreline (too close to the beach) reduces coastal stability, resulting in considerable coastal erosion. Human activities that exacerbate coastal erosion include coastal vegetation clearing, coral mining and reef breaking, and beach sand mining.
Muditha Katuwawala, coordinator at the Pearl Protectors, said that during the monsoons, there are erosions known as seasonal erosions, which occur when there are strong monsoons and powerful ocean currents, and the sand is carried away to the sea, a seasonal occurrence. He went on to state that the problem emerges during seasonal erosion, which this year has been found to be more severe than in past years.
He also stated that there has been significant seasonal erosion along the shorelines of Wellawatte and Agulana. Meanwhile, the ADBI study identified an unstable coastal zone all along the Colombo Coast, with moderate erosion in Mount Lavinia and Wellawatta beaches and severe seasonal erosion in the Colombo District, primarily during the Southwest Monsoon. “However, erosion along the coast, including Dehiwala, Mount Lavinia, and Wellawatta beaches, is not a permanent feature. Erosion is affected by the seasons, and accretion begins with the entrance of the warm-weather North-Eastern monsoon.”
Irregular sand dredging
According to Katuwawala, the natural sand equilibrium on the shoreline is no longer present. He said the Sri Lankan coastline generally obtains sand from our rivers, and when sand is dredged from the rivers, no sand is carried out to sea. He said when this occurs, there is insufficient sand to cover the shoreline, and the sand is unbalanced. “It is unethical to dredge sand from rivers.
Sand dredging has increased dramatically in the last two years, which could have a long-term impact on this excess erosion. The third cause is coastal building. Coastal construction projects are being undertaken by individuals, businesses, and the Government as a whole. One of the Government-run coastal projects is the Ports City or Mount Lavinia beach nourishment. Building hotels near beaches is a major threat to shorelines,” he warned.
What happened to the coastal buffer zone?
The shoreline buffer zone is a strip of land around the border of lakes and other bodies of water. This zone, in its natural state, can help protect aquatic habitats by functioning as a pollution barrier. However, in order to play its full role, this zone must be large enough, entirely for native species, and separated into three strata: grasses, shrubs, and trees. Speaking about the importance of a buffer zone and the consequences of not having one, Katuwawala noted that anyone building hotels near beaches should consider the buffer zone, adding that without one, there is no buffer to protect the shoreline, which can result in much faster erosion of the shoreline.
“As a result of people, houses begin to spread on the shoreline and beaches, and there is no actual buffer established to protect the seashore when this occurs. The Wellawatte beachfront is a well-known example. “The beach in Wellawatte is collapsing due to a lack of natural stability in the shoreline,” he explained. Finally, Katuwawala expressed that when he visits communities every five years, one of the most prevalent remarks she hears is that there has been significant seasonal erosion in the recent five to ten years compared to previous years.
“These aspects must be fully examined in Sri Lanka, which is cu rrently not happening, and we are striving to correct this. We have noticed that some sand is returning to the shores at the moment,” he remarked. However, everyone is now aware of the problem of coastline erosion, which raises the question of what the CC&CRMD, which is in charge of managing the coastal zone and its resources, has done to address the issue.
The goals of the CC&CRMD are to enhance the state of the coastal environment, develop and manage the shoreline, raise the living standards of coastal communities, and promote and assist economic growth based on coastal resources. The Department's overall purpose is to achieve "sustainable development of coastal resources and control of coastal processes to optimise Sri Lanka's social, economic, and environmental status." Ceylon Today spoke with Eng. L.D. Rununage, Chief Engineer (Coastal Development) at the CC&CRMD, who claimed that they are well aware that coastal erosion is occurring and that analysing coastal erosion patterns is one of their key measures for conserving the shoreline.
She said that high levels of erosion and threats to public and private properties, economic activities and utilities, as well as key habitats, are prioritised for protection under this plan, while appropriate monitoring procedures and site-specific management strategies are devised. She also emphasised that the Coastal Conservation Department is committed to promoting the use of alternative lime sources to meet the needs of the construction industry and agriculture, implementing recommended policy guidelines for coral reef climate change adaptation, and reducing over-exploitation of reef organisms such as aquarium fish and lobsters through appropriate management practises.
They also encourage and promote coral reef surveys and restoration by conducting collaborative research on these habitats and their resources, as well as developing platforms for information exchange and effective dissemination.
Coastal erosion is increasing
According to the study, increasing coastal erosion rates in Kalutara, Colombo, and Gampaha districts after 2000 may have been caused by the destruction of natural barriers such as corals and protective vegetation such as mangroves as a result of the vast destructive phenomenon of the tsunami, as well as different development projects that have carried out physical alteration of the shoreline over time.
It cited that Kalutara, which had an erosion rate of 50 per cent of its shoreline in 2000, saw it accelerate to 51.1 per cent by 2019, Colombo experienced an acceleration from 20-25 per cent to 35.86 per cent in the reference period, while Gampaha saw an acceleration from 30-35 per cent to 33.56 per cent. During this time span, Colombo's net erosion rate increased from 0.1m (2000) to 0.54m (2019). However, Puttalam District, which had an erosion rate of 0.2m in 2000, reversed this trend and now has an accretion rate of 0.026 metres by 2019.
Consequences on a Global Scale
Living creatures are required for the correct operation of coastal biogeochemical cycles. They are vulnerable to rapid changes in the coastal zone caused by anthropogenic activity, but changes in the structure of organism populations will alter the geochemistry of the environment, perhaps leading such cycles to fail. Changes in coastal ecosystems may have global consequences, causing an imbalance in energy and mineral flows along the landsea interface.