back water

基本解释

Engineering – How would you design a gravity dam for holding back water?
你会如何设计一座防洪大坝？
I hope they will be back to water next season.
我希望下赛季他们能回到水里头去。
The cooler sections of the tubing with turn the steam back to water and start to fill the empty can.
铜管较凉的那部分会把水蒸汽变成水，并开始流进空的容器里。
blog.sina.com.cn

It shows bloody images of fisherman cutting the fins off dead sharks then throwing them back in the water.
You've got to pretty much take that chalk, and make a slurry out of it, put water, and dry it back up, put in a mold, and then you can have the chalk again, but you can't just glue it back together.
你得尽可能地收集它的碎片，把它做成粉浆，加水然后风干，放进模具，然后你就能重新得到这支粉笔，但是你不能简单地把它粘起来。
麻省理工公开课 - 热力学与动力学课程节选
and getting back to balancing the elements in our lives, very basically like Earth, water, fire.
回归生命中元素的平衡，基本上就是土、水、火。
瑜伽的魅力 - SpeakingMax英语口语达人

Dams for irrigation, meanwhile, have a doubly damaging impact on fisheries: they not only hold back water, but also encourage the conversion of forest to farmland in the flood-plain.
ECONOMIST: The Mekong river

A backwater is a place that is isolated.
If you refer to a place or institution as a backwater, you think it is not developing properly because it is isolated from ideas and events in other places and institutions.