Way of Water monks have spiritual energy connecting them to the element of water. They can use their ki to control water, and use it when attacking those around them. 

Additional Spells

Starting at 3rd level, you learn additional spells. You know the Prestidigitation cantrip. You also have one use of Create or Destroy Water and Water Walk per long rest. 

Capsizing Wave

Starting at 6th level, you can create a wave. As an action, you can spend a ki point to create a wave in a line going out 30ft in front of you. Anyone in that line must make a Strength Saving Throw against your ki save DC. On a failed save, they get knocked prone and take 2d8 cold damage. On a successful save, they take half as much damage and don't fall prone. 

You can expect additional ki points to do an extra 1d8 damage per ki point spent. 

Watery Shield

Starting at 11th level, you can create a shield around yourself. As an action, you can create a shield around you, which lasts for one minute. Any ranged attacks that try to hit you will have disadvantage and you become resistant to Cold and Fire damage for the duration. 

Once you use this feature, you cannot do so again unless you complete a short or long rest. 

Ocean Connection

Starting at 17th level, your connection to the water grows strong. You have a swimming speed equal to your walking speed, and you suffer none of the disadvantages of being underwater. Furthermore you can breathe normally in water.