Kochi: Even as the state government moves to allow mining of four lakh cubic metres of sand from the Periyar and Bharatapuzha rivers while green activists protest, it is now known that sand audit as prescribed by the Kerala River Bank Protection and Regulation of Removal of Sand Act-2001 is due this year.
The Act was formed on the orders of the High Court which said that every three years the sand audit should be done. The last audit was done in 2009 by a team from Centre for Earth Sciences Studies (CESS), Thiruvananthapuram, led by scientist Dr D Padmalal. The audit had found the state of the river very weak.
After that sand audit, it was prescribed that only 1200 tonnes of sand should be mined from Periyar per day downstream of Malayattoor, under the jurisdiction of 11 local bodies, following strict guidelines. This should be viewed against the amount of sand mined from Periyar in 1998 which was 30,000 tonnes per day.
Scientists now prescribe ‘bed rest’ for Periyar as several parts of it have gone three metres below sea level. The Periyar river bed is now going down by 20 cm per year, the highest in the case of rivers in Kerala.
It has been prescribed that sand can be mined only up to three metres from the summer time water level. However, in the region from Kalady bridge to Aluva Pump House several pools having over 9 metres depth have been formed. From here no more sand can be mined.
The CESS’s last sand audit found that in several parts, the sand had given way to clay in the river bed threatening habitat as well. Except during monsoon, the pools remain stagnant threatening saline intrusion in summer which is prevented by the Pathalam bund.
It has been found in the audit that river bank sliding is severe in areas downstream of Malayattoor. A total of 15 sand bars which existed in 1975 have totally disappeared while eight sand islands have been partially damaged.
