impound
vt.
1 to shut up (an animal) in a pound
2 to take and hold (a document, funds, a vehicle, etc.) in legal custody
3 to gather and enclose (water) for irrigation, etc.
im[pound4ment
n.

A pond is a relatively small body of water resulting from a stream becoming blocked

A pound can be a enclosed place where stray animals can be kept until claimed by their owners.
Or destroyed if owners do not claim them.