Unlined pond / bioretention in clay, need advice to finish

Last fall I managed to dig this pond/ retention basin to collect the rainwater from our roof. We have non-draining clay soil. I have put in an overflow that leads to a ditch, and all winter the pond stayed full without adding water. The plan is to put in a waterfall, since I have a "mountain" next to the pond. But I am confused about what we need. I'm not planning on keeping koi in it, just some plants and probably some "throwaway" goldfish. I do want it to stay reasonably clean so the dog doesn't smell when she wades in. Right now, the bottom is covered with rotting leaves because we barely were able to finish the digging before the weather was unamenable in the fall.

The pond is roughly oval, about 14 X 20, and only about 18 inches deep average. The top of the "mountain" is about four feet above the surface of the water. Most of the filters I have seen are very expensive, and I wonder what I can get away with, since I'm not planning for fish. This is mostly a retention pond to handle drainage issues and gutter overflow, and to look pretty, and for the grandkids and dog to play.

Brenda

Cool idea-you will need to get that water moving or else it will stink and you will have a ton of mosquitoes. I just bought the fishmate brand bio filter with UV and the pump and am very, very, VERY happy with the quality and ease of cleaning it. It was a cheaper priced item comparitively but quality!

You could probably go to the bait shop and buy a bunch of minnows. they are winter hardy. will come up to the edge where the kids can see them, and eat the mosquitos.

A clay bottom pond shouldn't need a filter but you will need aeration. A waterfall could provide that, so then you will need a pump. I would think an external pump would work best because a submersible getting gunked up with clay and leaves. Not sure, but a very cool setting...that hill is just asking for a waterfall:) Good luck!

Thanks for the replies. Do any of you have a pump brand that I should be considering? I'm totally naive about this. I bought a little red tractor last year with a backhoe and loader, and next thing I knew I was digging a hole! It started out as a bioretention pond, just to collect drainage from the gutters and the yard, but I kept imagining a real pond and a waterfall .....

Are there any other clay lined retention ponds nearby that you can compare to? If there is a long period without rain, and with a big waterfall going, you'll lose a lot of water to evaporation and splash. You could wind up with a small sticky slippery puddle with no water to move. Does water collect and stand there in August?

Yes, it does. We generally have ample rain all year here in cleveland, and we have directed our roof gutters to fill the pond (more digging for me!) , And no more clay ponds that I know of. I guess this will be trial and error.

I am thinking that we will probably have to add water a couple of times in the summer, and I have also thought that if we could control the water movement (lower the flow over the fall ) we would lose less to evaporation.

My family is from Cleveland so I'm somewhat familier with the weather. Adding water is something that's individual to each pond. Here I have to add water every three dyas or so in the heat of the summer, even with rain, because I have a vigorous water fall. It will be a matter of trial and error the first couple of seasons. You always start to lose water when you start to move it and you absolutely need to move it. Otherwise as other posters have pointed out you'll have a green soupy, mosquito breeder that's possibly stinky. That great looking dog will L O V E it! Before you go pump shopping try to get an idea of how many gallons of water your pond holds. That's job one.

Try this:
http://futurepet.com/trivia/ponds-figuregallons.htm

Your dog ever chase fish? I had an English Pointer that one day found out he could swim and I couldn't keep him out of the water. He chased the fish swimming near shore in a lake. He fetched dead ones and then rolled in them. He was my all time favorite dog. Smelly, but oh what a dog. I give anything to have him back, stink and all.