Water Blast

A Beam of Water streaks from a water source within 30 ft (of you), toward a creature (within range), that you hit with an attack. Make a ranged spell attack against the target. On a hit, the target takes force damage based on how big the water source at least, 1d2 for 50 gallons, 1d4 for 500, 1d6 for 5,000, for 1d8 for 50,000, 1d10 for 500,000 gallons.

The spell creates more than one beam when you reach higher levels: two beams at 5th level, three beams at 11th level, and four beams at 17th level. You can direct the beams at the same target or at different ones. Make a separate attack roll for each beam.

Clarifications: You may use cast as part of your opportunity attack. If you cast water blast you may still use it on your turn. If the Water source is less the 50 gallons then you cast the spell but it doesn't deal damage.