I agree with CJ. I thought the pond was closer to 1 ac in size.
Like what sprkplug said, some things we'll never know. I was walking around in one small area of my pond today barefoot and felt something funny. Pulled it up and it was Chara in about 3-4' of water. Where did it come from? I have no idea.
Chara was the first living plant life-form in my pond, it was growing the first spring after my pond filled. That stuff must have spoors/pieces long buried on the soil that just wait until conditions are right. Now it is all over the place, but provides some interesting structure in the pond the fish seem to enjoy. Always see the larger fish hanging around the larger clumps of it while hunting. Cattails were the second addition, they were coming up like grass all over the inside basin of the pond, including down deep. Seeds must have been in the soil waiting for proper conditions.