I'd say 2 foot minimum then It's unlikely to freeze right through.
Our pond is a fish pond so ours is about a meter deep at one end going upto 50cm's the other. I think I read at the time of constructing ours that an ideal depth for wildlife should be around 60/90cm's for hybernating frogs. someone will correct me if I'm wrong . We have frogs laying ample spawn every year but very little survives with having fish!
I don't think you need slopes other than to get out of the water Sara and you don't need to do that all round if you fancy a steep bit. You don't need fish, a wild life pond is much more exciting.
Most of the shallow areas should be less than 50cm deep to allow for marginals and invertebrates to thrive.The deep area should be about 1m in order for frogs etc to over winter successfully. The deeper water is also good for a water lily to grow in.
I have created a similar pond to yours. It has been very successful and I have frogs, toads and newts.
I have had a few problems therefore maybe a few tips for you to think about or look out for: topping up the pond with only rain water has been a challenge. I now have 3 water butts to help with this in summer. About 25% of the sides of my pond bleed into grass and other plants on the bank and although it looks really natural and is well used my birds and mammals for access to the pond it does absorb quite a lot of water.
Blanket weed has also been a problem - common to most ponds at one time or another. This year I have followed Monty's advice and stuffed a leg of a pair of tights with barley straw (50g per square metre of surface of the pond), secured the other leg under a stone at the edge of the pond under foliage and am letting it rot down. It seems to be doing its thing!
The only other thing I would say is if you know someone with a pond, approach them about having some plants. Pond plants can be expensive - I don't know why as they all grow at a terrific rate and need splitting, cut back or pulled out on a regular basis.
Hope this is useful to you. Good luck with your pond - make it as big as you can because once you start putting in plants and the edging grows - it seems that it shrinks!
I don't blame you for not wanting fish sara, the pond is my husbands baby although he took a bit of persuading to make me an ornate pond cover to stop the heron's and next doors cats taking the fish, also to protect our grandaughter from falling in.
Its still waiting to be finished as he run out of steel, but once its painted up I think it will look quite sculptural. its loosly based on the blue peter one!
I should have continued with....we don't have marginals just oxygenators and water lily's. Our last pond we had marginals and didn't have a problem keeping clear water. This one is wick with blanket weed that I have suggested trying the barley straw. I've even sugested we put a plastic crate in the bottom of this one to put marginals at the shallow end to see if it helps control the weed. We also have the filters running with a UV but still its green.
My pond is wild and wooly and you can hardly see the water at the moment!
This taken from the main pond end. It narrows goes under a large stone slab (recycled) which acts as a bridge and path and then the beach end...which is where the next picture was taken from...
You can see that the level has dropped at the moment. We have been promised rain so I am holding off on topping up. There is also rather a lot of duck weed but I can't do anything about that at the moment without removing a lot of tadpoles so I'll wait until they hop off.
The water is pretty clear at the moment, thanks to the barley straw I think.
Chuckled at the coat hangers and sticky back plastic! Good luck with it all Sara it will be lovely to watch your project evolve, Have you thought about bloging it? I started to blog our house extension last year. I thought it would be informative for anyone thinking of doing their own extension, its lovely to look back on it.
Ha haa can't wait for christmas.....
I only blogged (wrote) as far as the roof! its a long story why I never got around to the finished build that I don't want to bore you with. I keep saying I'll re-write it and put it in better order you need to scroll down to the bottom to start at the begining. The actual buil was the easy bit, the internals was where the nightmare begun!
Your so eloquent in writing, You could do your own writing about you pond build in word then publish it on blogger which you can sign up with google...we built this extension with very few tradesmen and on a very tight budget, we hired brickies by the day, we hired the joiners by the day,as well as the roofer and plasterer although we fitted all the plaster board. My husband did all the plumbing & electrics (although we had to have a certified leccy to over see the installation) Husband and I fitted the kitchen, layed the floors and I did all the painting and decorating. Our problems began when we found wood boring weavil in the old parquet flooring, every downstairs floor had to come up and renewed. It was then I couldn't write about it anymore I'd about lost the will to live. It took us 8 months. I need to rewrite the experience.
Sorry folks for taking over this thread, the moral of it all is that you can construct anything. the internet is a fabulous place for information on how to???