Weir

These are weirs, says the water engineer.

I only knew a weir in theory that there is such a word when I played Scrabble.

A weir (IPA: /wɪɚ/) (also known as a lowhead dam) is a small overflow-type dam commonly used to raise the level of a river or stream. Weirs have traditionally been used to create mill ponds in such places. Water flows over the top of a weir, although some weirs have sluice gates which release water at a level below the top of the weir. The crest of an overflow spillway on a large dam is often called a weir.

http://en.wikipedia.org/wiki/Weir

I used to grit my teeth when we had to drive miles and miles, and walk miles and miles to see an engineering structure. Not any more, we met an engineer's kid, and he descibed the same feeling as me. Much later, I met an engineer's wife, and she too, talked about the same thing. Now, I just follow along, as we drive and walk miles and miles.

There is a Chinese saying, JIA JI SUI JI, meaning, marry a chicken, follow a chicken,
JIA GOU SUI GOU, marry a dog, follow a dog.