Human intervention in the form of two breakwaters aimed at checking the easy flow of water has proved disastrous, eating into the natural beach along Cherai-Munambam.
A recent study by a team of scientists from the Geological Survey of India led by P. Praveen Kumar says over the decade since two breakwaters were set up in 2000 on the estuary mouth at Munambam, the situation has worsened.
Owing to the littoral drift and sediment movement during the flood and ebb tides, two spits were formed at the Periyar estuary mouth - Azhikode and Munambam.
To avert navigational hazards posed by the sand bar as well as the growth of the spits, breakwaters were set up by the department of harbour engineering.
The sand bar near the mouth was also dredged to maintain channel depth for easy movement of vessels.
As a result, only a limited quantity of sediment was available during the flow of water and erosion continued at the beaches, they say.
The construction of breakwaters on either banks of the Periyar estuary temporarily caused stabilisation of the beaches, but over the years with the flow of only empty water, erosion of the beaches would occur, Praveen said.
He pointed to the report of the irrigation department in 2005 which said in the Cherai area, about 7 km length of the beach had been formed and the old sea wall was covered with accreted beach sand.
However, the present situation is different. The shoreline from Munambam to Cherai is now fortified with very high sea walls, thus obviating the aesthetics of this tourist spot.
Even seawall boulders are getting dislodged. The soft options are dune vegetation and rehabilitation, sand fencing and artificial beach replenishment.