I ran these tonight basically as they were statted out here, where we played through our city's version of the events in Aftermath. Worked well. Their ability w/ regards to water is especially potent when facing other sorcerers; add in a sprinkler system for true fun. However, my players just hexed those, then tossed area effect spells at them and took down the whole lot pretty easily; leaving the sorcerer to contend with. Due to a big, fiery finish, no one knows if he lived or not.
Of course he did; my players metagame-ingly assume this (because what fun is it for the story if he died?)
I had the sorcerer pump shifts into a really big darkness spell, to maximize their sonar advantage. This also worked well; it was countered briefly (someone dumped a light spell with more shifts of power but less duration into the area, but didn't target this as a counter... so they just lit the area for a few rounds).
To sum up: add in sprinklers and a powerful darkness spell, and these guys are really in their element.