The River Clodiagh () is a small river which rises in Lough Coumduala in the Comeragh Mountains in north County Waterford. It flows through the villages of Rathgormack, Clonea-Power and Portlaw before joining the River Suir just outside Portlaw. The river is fed by a number of smaller tributaries including Hunts stream and Aughtnawilliam stream.
The river is used for canoeing, kayaking and fishing. In April 2010, two canoeists on a sit-on kayak drowned after being stuck in a weir at Portlaw.
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