IPA: /ˈteɪlˌwɔːtə/
KK: /ˈteɪlˌwɔtər/
Water that is found just downstream from a dam or other structure, often affected by the flow and management of the water above it.
The fish thrive in the tailwater below the dam, where the current is gentle and the water is rich in nutrients.
Tailwater → The word is formed from "tail" (from Old English "tægel", meaning the rear or end part) and "water" (from Old English "wæter", meaning water). Tailwater refers to the water located downstream from a dam or other structure, specifically the water that flows away from the tail end of such structures.
Think of the 'rear part' ('tail') of a structure where the 'water' flows away — that's what tailwater means.