A couple of alternatives, based on the Trans Hannoni variations (See Note on Alternative versions) might be the Hodni stream (Nant Honddu, pronounced Hon-th-i?) which runs by Llanthony Priory (Priordy Llanddewi Nant Hodni), or, more likely, the river with the same name which runs down to Brecon to join the Usk (Visit Details). The latter was mentioned with this name by Gerald of Wales* (1197 C.E.: Book 1, Chapter II), who was archdeacon of Aberhodni (Brecknock / Brecon). The advantage with this river is it is close to the other wonders, the Severn bore, and the marvellous Lake Llangors (see Wonder 1, Note on Lake), however, the description of the wonder does not, as far as is ascertainable, fit either (the Usk is currently only tidal to Newbridge on Usk*). To move further from the name we might also note Hod(d)nant, now Llantwit on the Severn* though this really stretches credulity.
NB: The Priory was moved (details) to just outside Gloucester, so the name at this location is a copy of the original, rather than having a parallel geographical etymon.