Water Surge

As an action, a quick stream of water forms a 30 foot long and 5 foot wide line out from you in a direction you choose. Each creature in the line must make a Dexterity saving throw. A creature takes 6d6 bludgeoning damage and is knocked prone on a failed save, or only takes half as much damage on a succesful one. 

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, you increase the damage by 1d6 for each spell slot above 3rd level.