intake tower; outlet tower
A tower-like structure built in a reservoir or lake to draw water into a dam or water supply system. The term covers both intake and outlet functions depending on context.
An intake tower stands in the middle of the dam lake.
Water flows from the intake tower into the penstock.
放水塔 is an outlet tower for releasing water, whereas 取水塔 can serve both intake and outlet purposes.
Compound of 取水 (water intake) and 塔 (tower). The exact historical derivation is uncertain, but the term is a straightforward technical compound.