Unscientific dredging at Thottappally spillway adds to salinity, finds survey

Bottom salinity at certain points in the leading channel has exceeded 2 ppt, the allowable salinity limit for rice, as per an IRTCBSF survey. Expert calls for an end to deep dredging that leads to trapping of saline water in mining pits. Though the saline concentration is not serious enough to cause alarm, farmers are advised to use only surface waters for irrigation.