An old water tank

Since I'm always searching for step wells, this landmark was interesting to me.
At one time it must have been a man made tank, but now the water is all dried up--within the last five years even, the residents told me. 

There is evidence of walls and possibly stairs, but it's all buried by dirt and weeds.

Now it's just a big crater in the ground behind the neighborhood.
The way water sources shift and history is overgrown and forgotten is fascinating to me.  Somewhere, someone knows this story--it's just a matter of finding that person.