20m x 20m new pond, low maintenance

[jnorris235]

I have read many threads but dare to ask some basic questions, please.
We are replacing two 10m sq ponds, designed as sewage ponds. Apart from removing some vegetation these were maintenance free, had fish and frogs in one, newts in the other. But dangerous as the centre was 2m deep and the sides steep.
We’d like to replace them with a much safer, clear water and shallower pond. We dont necessarily want fish, dont like them! As maintenance free as possible. I know how good I am at maintaining things.
My image is of a beach of pebbles with an island in the middle (we have a large weeping willow), and a duck house (just a few ducks). Maybe 0.5m in the deepest part around the island.
I’m guessing this will need to be at least 15m sq. About 60,000 litres. Hopefully that is enough?
Q1. Is butyl the best way to make this? I mean just what do you do after 20 years if it degrades? I notice all over France farmers install large reservoirs - I wondered if they had a better material?
Q2. Assume a waterfall and bog garden is the cheapest way to get clear water without spending money on filters?
Q3. Is it a bood idea to cover at least the edges a metre or two in in pebbles? Or do they just attract algae etc?

 

[sissy]

welcome and we use epdm 45 mil pond liners .Ducks can be messy so you will need a good filter

 

[addy1]

Assume a waterfall and bog garden is the cheapest way to get clear water without spending money on filters?

I filter my ponds with just a large bog full of plants. My bog is around 1/3 the size of the pond.

 

[Mmathis]

Hello and welcome! Pictures of the existing sites would be helpful.

 

[Mmathis]

@jnorris235 Are your current ponds natural or are they lined? You mention large reservoirs in France, but do you know if those are natural or lined? They could just be natural, earthen ponds. If they are lined ponds, then the life span of a good 45 mil EPDM liner (is that what you are calling butyl?) is about 20 years. Here, if a liner degrades or is damaged by nature or critters, it’s usually dug up and redone — but most of us are constantly tweaking our ponds, so not sure how many of us actually keeps one liner for that long. EPDM 45 mil is what most of us use.

You are going to get algae in a pond no matter how deep it is or whether you have pebbles. Algae is not a bad thing and is part of a healthy pond ecosystem. A lot of us have a bog filtration system of some sort...very efficient, but you’re still going to need a good pump. @addy1 had an excellent thread about bogs, but you’ve likely already read through that.

 

[Stephen Noble]

So in summary, do you want to convert old cesspools to some sort of water feature that will not have fish?

 

[Mmathis]

@jnorris235 I went back and looked at your older threads & posts from 2012 on. Sounds like this is something you’ve been sitting on for a while. Did you decide not to combine the 3 (or 2) ponds? And what came of your copper tree?
https://www.gardenpondforum.com/threads/oh-joy-3-ponds-can-they-be-joined.9599/