[Tyrant]

River does nothing unless it's a player made map that's set up so it does.

As to the water gems- Boots of Quickness and Bottle of Living Water are great items, you can never really have too many. Frost Brands are pretty much the best sword you can buy and a bargain at 5 gems. You will want Water Braclets for anyone who plans to use Falling Frost. Ice Drakes have uses and Winter Wolves are ok.