I saw your post yesterday and surprised no one has responded.
We live in zone 7 and have no problem with freezing pipes etc.
We've had winters where the ice on top of the pond is 8" deep.

I believe you'll have to go a little deeper in one section for the fish to overwinter in zone 4. We have a 3 1/2 foot section
and our fish overwinter in that part of the pond.

We have a bottom drain, and a DIY gravity fed filter system.
If you want koi, you should consider putting in a bigger pond, if you just want a few goldfish your size is adequate.

This is basically how we did ours (in the beginning) We used three tubs buried in the ground, the water level in the tubs are the same as the pond. The pump(s) are in the last tub. After the water goes through all the tubs it returns to the pond.

After that (the next year) we added a biological pond that the water travels to via underground, goes through a biological pond then returns to the main pond. I'm an not suggesting that method for you, only explaining that later on we needed more filtration cause we had a lot of koi.
I am providing the link to our pond plans and diagrams for you. Once you get there check out the links on our website and go to Chuck Rush's website for good information.
You have this entire winter to think things through and that's a good thing. Starting out knowing you want a bottom drain is a good thing as well, as it is the single most important thing you'll do for your pond. Everything else you can improve upon later. For instance we added our skimmer the second year. Again it was a DIY job, and it's housed under the small dock on back of our pond. We only use the skimmer is spring and fall.

If you want shelves all around for a very natural look, here is how we did ours, dig a shelf all around pile flat rock and round rocks too, up to ground level then on the ground as well, in between you can move the rocks and plant hidden pots with plants. When you look into the pond you will not see any liner all around the perimeter of the pond.

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Welcome to the forum and good luck with your armchair pond planing! In the mean time I hope some zone 4 ponders jump in here.

Joann

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Here is a link that might be useful: Pond plans and diagrams

Thanks Joann:
Actually, your website was already saved to my favorites and I have been there several times admiring your photos. You really have a beautiful pond and yard.
To anwswer your question - No. I don't think I want to keep koi - I kinda like goldfish better. I guess I may need to go a little deeper though - I need to check out the zoning at the new house before I decide.
I definitly want a natural looking pond - I want to blend it into the landscape. The yard and surrounding neighborhood is simi-wooded - a nice mixture. I know I will have leaves - therefore the bottom drain and skimmer. I have a tree overhanging my current pond and I am tired of all the netting, vacumming, and pulling the pump up every few days.
I am still looking for info on how to deal with the freezing weather and the skimmer, pump and pipes.

Jeff

oh gosh Jeff, I thought you were a newbee.
I hope some zone 4 ponders jump in here and
help ya.

Joann

I have two bottom drains and a skimmer that are plumbed to mechanical barrel filters, an external pump and a biological filter. Before the pond freezes, I plug the bottom drains and empty the barrels. The bottom drain lines seem to drain automatically (gravity fed). When I remove the pump, the line from the pump to the biological filter drains as well.

I don't empty the skimmer or the biological filter - they freeze solid and so far no problems with that. But I do put some styrofoam noodles (kids water toys) in the skimmer to absorb some of the effects of expansion (I don't know if this really works, but I read it somewhere).

Hope that helps some. This is only my second winter so my experience is somewhat limited, but it has worked so far. I'm in zone 5 - we do have sub-zero temps, but not usually 20-30 below.

i have a partialy raised formal pond with a tiered fountain. i leave it running year long and the fish stay in itÂnever lost one in winter. i built it like a swimming pool. skimmer and bottom drain (skimmer in the wall). the skimmer and the bottom drain share a pipe so the skimmer can never run dry if the water level is too low. i have a preasure filter above ground in the corner of the yard. the pipes are all 2 feet under ground except when the surface for the pump. i keep them flowing to avoid freezing. i also wrapped all the pipes with the rain gutter defrosting wires you can get at home depot. never used them, but i can turn them on if a pipe ever freezes. last year i did not cover the pond and all was fine except the concrete fountain cracked. this year i covered with a tarp and have no ice on the pond at all and we have been in the teens for a few weeks. i know a lot of people don't like pressure filters and they have good reasons. i love mine compared to other systems i have tried. it helps in the winter to have it all contained. if i had built the house new i would have put it inside the house or garage and all the pipe would have been buried. i am pretty proud of it compared to past ponds done in a more traditional manner.

if this makes no sense, or you want more info/diagrams contact me and i will post more or give you a phone # and we can talk.

A great website for info that will help you is www.pondkoi.com..there is a forum there too .I have a new pond similar to what you are thinking of doing mine is 5x8 & 700 gals. that site has helped me alot. The admin. there really knows what they R talking about. All their products are free shipping too which to me is a plus....

i,m redoing my pond of 15 years this spring i would like to change a few things to make it better.i,m digging it deeper and removing ledges.one big question is the last builder used concrete over the dirt hole.my liner is leaking somewhere that maybe the cause.what do you recomend behind the liner, sand, carpet, felt liner ?

we live in toronto canada, your best option for winter is to stop filtration, take filters and uv units in side, keep all filters empty and keep air stones in the pond for winter. You can also build a greenhouse over the pond to help with ice, or use a de-icer, they work great.

Here is a link that might be useful: clarke koi