noun
force of water; water pressure; strength of a current
Refers to the power or momentum of flowing water, such as in a river, stream, or water jet.
大雨で川の水勢が増した。
The force of the river's current increased due to the heavy rain.
消防士は水勢を強めて火に当てた。
The firefighter increased the water pressure and aimed it at the fire.