Compare the power blocks; this looks like it's been heavily reskinned. The power labeled as "Freezing Current" is actually freezing burst
, from Heroes of the Fallen Lands
. You're on your own for the rest.
However, if it's a water-themed spellcaster you're looking for? Have a look at the sorcerer (elementalist) in Heroes of the Elemental Chaos
. One build for each classical element, water included, though of course I prefer FIRE because of its absolute superiority among damage types.