“Well formation could be due to removal of sand by someone, which worsened due to the marine action. It’s strange that turbulent activities are witnessed post-monsoon too,” this is what Antonio Mascarenhas says. Do we need ask who could the culprits be? It is a well known fact that most shacks sand mine from the beach and use the sand, packed in gunny bags as foundation for their shacks, many a times snad dunes are destroyed in the process and sometimes natural vegetation as well . These are natural protectors of the coast from storms, floods etc.
https://timesofindia.indiatimes.com/city/goa/mighty-waves-eat-into-few-south-goa-beaches/articleshow/62343459.cms
High tidal waves have led to removal of sand dune sediments, allowing seawater to chart its own course beyond the beaches at certain stretches spanning from Colva to Benaulim. At many places, water ingressed into the sandy turf leading to a ‘well formation’.
The phenomena are more noticeable at Colva and Sernabatim, where tourists flock in large numbers. A fisherman tending to his nets said, “Well formation could be due to whirlpoola caused by a sudden surge of water.”