Written by Charitha Pattiarachi
Several statements regarding the beach nourishment project conducted by the Coast Conservation and Coastal Resource Management Department (CCD) have been recently shared across various social media platforms. The statements claiming that Mount Lavinia has successfully recovered as a result of the said nourishment are rather impulsive and, as a matter of fact, fictitious.
Globally, all beaches undergo seasonal variation due to changes in their respective incident wave climates. In Sri Lanka, the monsoon system dominates our wave climate. Therefore, the south-west coast experiences wide beaches during the north-east monsoon (November to April) and narrow beaches during the south-west monsoon (June to September). This is a natural cycle irrespective of beach nourishment. Thus, it is not surprising to observe a wide beach at Mount Lavinia at this time. Subsequently, the beaches will become narrower after the start of the south-west monsoon in the coming months.
In an article published in the Daily Mirror on the 1st of June 2020, the CCD announced the decision to spend 890 million LKR without both an Environmental Impact Assessment and a scientific study on the sand budget of the coastline 1. The project was undertaken with the assurance that the nourished beach would last at least five years 1. However, a few days after the sand filling that took place last year a significant amount of sand from Mount Lavinia, Angulana & Kalutara Kalido beach were washed away (figure 1). In response to the justification of the beach nourishment project put forward by the CCD, Oceanswell teamed up with Prof. Charitha Pattiaratchi, Sri Lankan oceanographer based at the University of Western Australia to do a quick analysis of what the CCD should have thought of, why things looked the way they did and what should have been done next 2.
As part of a collaborative project between Oceanswell and the University of Western Australia, fortnightly beach surveys between Mount Lavinia and Wellawatte have been undertaken since 18 June 2020 to monitor beach changes following the beach nourishment. Preliminary data analysis has shown no significant accretion between Mount Lavinia and Wellawatte except for season variation between Siripala Road and Sri Dharmapala Mawatha. The project is currently ongoing, and the final conclusions will be published in due course.
In the statement released, Coast Conservation and Coastal Resource Management Department claimed that “The pattern of sand accretion/deposition repeats at the canal outlets at Dehiwala and Wellawatte” and subsequently that “The coastal structures had been built to prevent sand deposition at the outlet to keep it open” 3. Despite the statement, a hill of sand can still be found accompanying the Dehiwala groyne (Figure 2), after the Dehiwala canal was dredged in July 2020 (Figure 3). The Wellawatte canal was seen being cleared out of sand only last weekend, 27th of March 2021 (figure 4).
Therefore, it is imperative to wait a few more months to assess whether the present beach would be sustained during the next monsoon season. The recent claims lack a scientific foundation and we kindly request the public to be vigilant of the portrayal of this failure in a positive sense.
- Colombo South beach nourishment project a success: CCD. Daily Mirror (2020). Retrieved 26 March 2021, from http://www.dailymirror.lk/breaking_news/Colombo-Southbeach-nourishment-project-a-success-CCD/108-189291.
- Pattiaratchi, C., Azmy, N. and de Vos, A., 2020. The tragedy of Mount Lavinia beach. Loris, 29(1), 60-63.
- Artificial beach between Kalutara and Mount Lavinia is a success: Coast Conservation Dept. Daily Mirror (2021). Retrieved 26 March 2021, from http://www.dailymirror.lk/breaking_news/Artificial-beach-between-Kalutara-and-Mount-Lavinia-is-a-success-Coast-Conservation-Dept/108-208486 Pattiaratchi, C., Azmy, N. and de Vos, A., 2020. The tragedy of Mount Lavinia beach. Loris, 29(1), 60-63.