N. B. Narasimha Prasad, Director of the Centre for Water Resources Development and Management, Kozhikode, clarified on Saturday that the marking of certain parts of Mullaperiyar catchment as falling in Tamil Nadu in the Water Atlas of Kerala (1995) was an error.

Mr. Prasad told The Hindu that the error had been corrected years ago and those concerned had been informed of the matter. It is a settled issue that it was a mistake.

He said that the Centre had since revised the atlas and it would be published once it gets the clearance of the Survey of India regarding State boundaries and related matters. The new atlas was being readied in the digital form.

The error had not initially come to the notice of the Centre. It realised the mistake only when Tamil Nadu made a claim based on that, Mr. Prasad said.

Former Minister for Water Resources of Tamil Nadu Durai Murugan had claimed in a rejoinder to the articles written by Ramaswamy R. Iyer, former Secretary, Union Ministry of Water Resources, and N. K. Premachandran, former Minister for Water Resources, in The Hindu that Mullaperiyar was an inter-State river, citing the Atlas.