Small pond incorporated into a raised bed planter.

[J68R]

Hello folks, hoping to get some feedback and direction about the idea I have here and above all any planning and prep I'll need to do for pipework filterwork etc. etc.

this is a (very) rough and ready sketch of the idea, alongside a progress so far photo. Footings are 350mm deep from the top of the flag. Plan to have the base course of blocks start somewhere below that level, perhaps 50mm or so.

The blocks I have are 7N concrete 440 x 215 x 135 mm and weight about 27kg each...

I'm asking for any suggestions, improvements, pitfalls etc. I have plans giving much more detail and dimensions, apologies for metric if that's not your thing.

Thanks in advance.

 

[j.w]

@J68R
Keep on digging, you have a ways to go

 

[J68R]

300mm footing is surely deep enough?

pond section walls/depth is going to be 3 block courses which will be ~700mm

 

[GBBUDD]

must be something in the water over there you brits just don't like to dig and build your ponds Like POND AND EXCAVATE .
yup not my thing . but i can say if you build with those blocks skinny side up i'd stay under 24" deep . with no rebar its not that strong. if the skinny is the height you maybe able to get up to 40" deep would be my guess

 

[J68R]

The blocks weight 4 stone each. The size of the pond, more of a water feature really, within a raised planter, is only 150 gallons.

I understand the friction between the mortar and the blocks is the weakest link just thought that would be plenty strong enough with the corner strength on top.

 

[GBBUDD]

Against 150 gallons your fine so long as your mortar isn't to wet

 

[J68R]

Thanks what a relief, I was starting to doubt my sanity. I'll most likely double skin the front part anyway just for safe measure but mostly to have a nice reddish coloured facing brick exterior to look at on the front and left side, rather than just big ugly grey blocks.

 

[GBBUDD]

Doing a brick veneer as well ? Stager your joints and you'll be fine. Your biggest issue will probably be the lack of a proper footing

 

[J68R]

I'd thought about some fancy stone cladding at one point but for the cost I might as well make a proper brick skin outer and have the advantage of some extra structural integrity.

When you say proper footing I'm intrigued what you mean. The concrete is sitting on a solid shale base which is at least another 2 feet deep down to the ground water table. I dug a trial pit some time ago and never got past the shale which was hard work getting through.

btw 150 UK gal. which is I believe approx. 180 US gal.

 

[j.w]

300mm footing is surely deep enough?

pond section walls/depth is going to be 3 block courses which will be ~700mm

I meant the digging of the pond part when I said keep digging! Where is the pond?

 

[J68R]

The forward section of the planter will be the pond with a bog filter waterfall thing going on when I finally decide how the heck I'm going to configure it.

Is it a bad idea to have the pipe from the pond going directly into the bottom fed bog filter and then have a pump in a separate compartment draw water through the bog filter and lift that water into the stream / water fall and ultimately back into the pond?

 

[GBBUDD]

Your design has issues imo

 

[GBBUDD]

For starters
As the bog starts to back up gather a little back pressure you pond water level will rise and over flow.

Your pump will empty out it's containment much faster than a couple gravity drains can refill the pump vault.

 

[J68R]

I see what you're saying and hadn't thought about the bog getting silted and choked up so badly it would stop feeding in to the pump. It's a small pond as you know and the bog filter I have in mind will be something like 200 litre / 50 UK gal. drum (not yet sourced) about a 3rd of the pond volume.
My idea from the sketch is that it can't overflow as the pump would lower the water level and stop feeding the pond long before the pond itself overflowed.
I dont envisage a large sump for the pump housing, just enough volume to sink it comfortably and have it sat in a relatively clean water reservoir to pump water coming from the bog via gravity / atmos. pressure up onto the stream and then back into the pond.
I'm no expert by any stretch... assumed a pump would have a safety of some sort if it did ever run dry? or perhaps I could have a go at making one via some sort of floatation switch.
Brilliant feedback, thanks so much, I have a lot to learn. I know the pond is tiny by most peoples standards but hoping the principles still apply.

 

[GBBUDD]

the smaller the pond the MUCH harder it is to get it balanced