A translator may decide to leave the original names or to translate them.
In the second case, translating Bridgewater to anything that contains "puente" and "agua" produces something unnatural, laughable or, at least, never heard of. Saying that you are the rightful duke of a doubtful place is a big oxymoron (that would be Cervantes' style).
That contradiction doesn't appear in the original version. Bridgewater is common in English and, for those who know more, there's a real Duke of Bridgewater.
So the translator needs avoid a reader's reaction that wasn't intended by the author. "Aguasclaras" sounds natural and, for those who know more, there's a real Marqués de Aguas Claras.