I'm a little slow responding 'cause I was laughing so hard I had tears in my eyes.
I know about tanks. We called them farm tanks. Most of them were earth dams in ravines.
Sometimes we dug tanks to catch runoff and sometimes around a spring.

We advertised that we did site development, grading, and farm tanks.
We got phone calls wanting to know what the tanks were made of and how many gallon capacity.
We changed our ad to farm ponds and received calls to dig them all over Michigan.

They are called a bunch of different things but they are still a hole in the ground.