The water below a dam, usually in a river or stream.
Tailwater is often calm and slow-moving, and it can be important for the environment and for people who use the water for different things.
Examples:
The fish like to swim in the tailwater.
We can fish in the tailwater.
The tailwater is very calm.
The tailwater is a good place to find fish.
The tailwater is the best place to fish in the whole river.
The tailwater is where the fish like to be.