Signatures of coastal erosion in the Pacific
Both natural and manmade processes are contributing to the ongoing risk of erosion along Samoa’s coastline. During a recent visit I was able to see several signatures of coastal erosion due to beach sand mining. At a local scale this is likely to result in only a small quantity of sand being manually removed from the beach when compared to the overall sediment budget. However, for any areas currently experiencing a net loss of sand it will accelerate erosion, and at larger quantities could affected the most stable beaches.
Common signatures of this coastal erosion are the landward movement of the beach, starting with erosion to the first line of palm trees, and continuing to the common beach fales, roads and any utilities located along the foreshore.
For several local references see:
When under threat of erosion, it is common to consider a seawall as the fastest and most effective way to stabilise the coastline. But these often bring other problems, with the loss of the high-tide beach and their tendency to accelerate erosion on adjacent land.
So what can be done?
I am glad to see many initiatives taking place throughout the pacific, championed by the Secretariat of the Pacific Regional Environment Programme (SPREP). It includes this is a very useful guide to Ecosystem Based Adaptation, that I might very well start incorporating into our work in Australia:
Another approach undertaken in the neighbouring island nation of Tonga has involved switching to an offshore sand source. Whilst a more costly option, this will also play a part in the long term sustainability of their beaches. Find out more here: http://www.looptonga.com/tonga-news/offshore-sand-mining-alternative-beach-sands-begins-fafaa-island-51551