Control water

Control water, also known as lower water and its reverse, raise water, was a transmutation/alteration spell that allowed the caster to gain some control over a body of water.

Effects
The older versions of this spell reduced or increased the water level of a cistern, stream, river, pond, lake, or other body of water. The area of effect was a square at least 70 ft (21.3 m) on a side, or even bigger for more experienced spellcasters. One version allowed the caster to double one dimension and halve the other. The oldest versions of this spell took 10 minutes to cast and lasted 5 minutes per level of the caster. The next version lasted twice as long and took only a few seconds to cast.

If the caster chose lower water, the surface dropped at least 14 ft (4.3 m) or more, but was limited to a minimum depth of 1 in (2.5 cm). If the target body of water was very large and deep compared to the area of this spell, a whirlpool was created that could trap vessels for the duration of the spell and possibly swamp or sink them. If cast upon a water elemental or a similar water-based creature, it acted as a slow spell on that creature.

If the caster chose raise water, the surface rose to either the highest naturally occurring level (high tide or a typical yearly maximum flood stage) or uplifted a volume of water similar in size and shape to the lower water version. Vessels lifted in this manner slid down one side of the watery hump as gravity dictated.

The post-Second Sundering version could effect a cube of up to 100 ft (30 m) on a side and would last for up to 10 minutes as long as the caster maintained concentration on the spell. The caster could chose between flood, part water, redirect flow, and whirlpool effects.

Flood would raise still water about 20 ft (6.1 m). If placed in a large body of water, it would create a 20 ft (6.1 m) wave that traveled from one side of the area to the other before crashing, and repeat this every couple of seconds unless another effect was chosen or until the spell ended. These waves would carry smaller vessels away or batter larger vessels as if they were in a stormy sea.

Part water would make a trough of air from one end of the area of effect to the other, piling up the water to form walls on either side. The passage remained for the duration of the spell or another effect was chosen, whichever came first.

Redirect flow would make already flowing water alter course to a path chosen by the caster. The path could be over obstacles, up walls, across ceilings, through openings, etc. If the water moved outside the area of effect, then normal water movement immediately resumed at that point.

Whirlpool only functioned if the volume of water was at least 50 ft (15.2 m) square and 25 ft (7.6 m) deep. The spell would form a vortex 25 ft (7.6 m) deep, 5 ft (1.5 m) across the base and up to 50 ft (15.2 m) across the top. Anything floating or swimming in the water within 25 ft (7.6 m) of the edge of the vortex was drawn toward it. Creatures could swim away if they were strong enough, but once caught in the vortex they were pummeled repeatedly until they managed to escape or the spell ended.

Components
All versions needed vocal and somatic components. The oldest versions needed a vial of water for raise water or a vial of dust for lower water. Later versions reduced the material component to just a drop of water or a pinch of dust. The post-Second Sundering version needed both water and dust to cast.