Interaction between canal water and groundwater in the Uda Walawe irrigation system:hydrochemistry and isotopes Mauro Prado, Kevin Hiscock, Lorraine Rajasooriyar, Eline Boelee Universities of East Anglia , Jaffna & International Water Management Institute Presented at Session C "Innovation and Technologies" of International Symposium 2010, Ruhuna University, Sri Lanka November 16, 2010