Unfortunately, I can't come over and clean up your pond and figure it out but I'll bet someone from your local watergarden society would be willing to help. Of course, I can't find one listed.
The black bucket is probably a biological filter and the white pole some pipe to move the water. Is there any moving water anywhere? It sounds like the equipment is busted, and the pond was left to degrade. With all those leaves and mud in there, the pond probably has to be drained, cleaned, etc. and the equipment fixed. In the process, you would find out what fish and plants are left in there. There are companies who will do this for you. This is the kind of thing I'd like to do (if I had the time, you were nearby, etc.) but can't. I hope you can find someone to help. The MAKC at
http://www.makc.com/ has some NJ groups so you might start there. They can help even if the pond has no koi in it.