Lower Water {Wizard}

A wizard casting a lower water spell causes water or similar fluid in the area of effect to sink away. The water can be lowered up to two feet for every experience level of the wizard, to a minimum depth of one inch. The water is lowered within a square area whose sides are 10 feet long per caster level. Thus, a 12th-level wizard affects a volume 24' x 120' x 120', a 13th-level caster a volume of 26' x 130' x 130', and so on. In extremely large and deep bodies of water, such as deep ocean, the spell creates a whirlpool that sweeps ships and similar craft downward, putting them at risk and rendering them unable to leave by normal movement for the duration of the spell. When cast on water elementals and other water-based creatures, this spell acts as a slow spell: the creature moves at half speed and makes half the number of attacks each round. It has no effect on other creatures.

Reverse: Raise Water

Its reverse, raise water, causes water or similar fluids to return to their highest natural level: spring flood, high tide, etc. This can make fords impassable, float grounded ships, and may even sweep away bridges at the referee's option. It negates lower water and vice versa.

[Player's Handbook]

Reversible

School: Alteration
Level: 6
Rarity: Common

Range: 80 yards
Components: V, S, M
Duration: 5 rounds/level
Casting Time: 1 turn
Area of Effect: 10-foot square area/level
Saving Throw: None

Material Components:
Lower Water: a small vial of dust (consumed)
Raise Water: a small vial of water (consumed)