flood-control works; riparian works
Refers to civil engineering projects aimed at controlling rivers, preventing floods, and managing waterways. Often used in news and technical contexts.
Flood-control works are being carried out in this area.
Thanks to the riparian works, river flooding has decreased.
治水 is the broader concept of flood control or river management, while 治水工事 specifically refers to the construction works involved.
河川工事 is a more general term for river engineering works, which may include dredging, bank reinforcement, etc., not necessarily limited to flood control.
Compound of 治水 (flood control) and 工事 (construction work). The term is straightforward and modern, with no obscure historical derivation.