I plan on building an elevated pond next to my porch. I'll encase it with treated plywood and add planter boxes to try and camouflage the edges. Would a bottom drain put in low on one side work as well as one actually in the center on the bottom?
Bottom drain on side?
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j.w
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I don't have one myself but have heard of peeps forming a low area where they install one and so I wouldn't think it would matter if center or not but I'm no expert. If putting on the side could you make that side area lower than the rest of the pond so gunk would have a tendency to run to that point?
I don't think one in the side near the bottom would work very well. These things take in stuff off the bottom. A side drain would only get some suspended stuff which would probably stay suspended, go through all filters and back into the pond.
You can however extend through the side out into the pond, add a 90 down to maybe 1/2" off the bottom. That would suck stuff off the bottom. And when going through the side it doesn't have to be near the bottom. You can go though just below the water surface and down, then over.
If you could build a small section out over the edge of the porch and dropped that part lower, it would be a perfect catch. And the drain could be up through the bottom. A small deep drop catch would work really well I'd guess.
You don't need any slope, but a small depression around the drain helps because the water in the depression will be more calm and stuff will fall out there. Or get pushed along the bottom, fall into the depression and not have enough energy to lift out.
A drain certainly doesn't have to be in the center. It's a common location because that the easiest setup with tangential returns. Tangential returns are 50% of a bottom drain system. You don't need to buy a tangential return, you can just direct normal water flow to set up the desired current. My waterfall catch basin did that. Water exited right at the bottom and pushed stuff to one side. However, stuff accumulated along the entire side, not in one place. With a circular motion stuff will accumulate in a single spot, hence the drain going there.
In water gardening tangential returns are often ignored. But without something pushing stuff to the drain they're pretty much worthless. Most people think gravity moves stuff toward drains and so think sloped sides are the key. But they're wrong. Sloped sides only work if you're trying to remove marbles or golfballs. The stuff we want to remove is almost buoyant neutral, gravity has virtually no effect.
Waterfall catch basin:
You can however extend through the side out into the pond, add a 90 down to maybe 1/2" off the bottom. That would suck stuff off the bottom. And when going through the side it doesn't have to be near the bottom. You can go though just below the water surface and down, then over.
If you could build a small section out over the edge of the porch and dropped that part lower, it would be a perfect catch. And the drain could be up through the bottom. A small deep drop catch would work really well I'd guess.
You don't need any slope, but a small depression around the drain helps because the water in the depression will be more calm and stuff will fall out there. Or get pushed along the bottom, fall into the depression and not have enough energy to lift out.
A drain certainly doesn't have to be in the center. It's a common location because that the easiest setup with tangential returns. Tangential returns are 50% of a bottom drain system. You don't need to buy a tangential return, you can just direct normal water flow to set up the desired current. My waterfall catch basin did that. Water exited right at the bottom and pushed stuff to one side. However, stuff accumulated along the entire side, not in one place. With a circular motion stuff will accumulate in a single spot, hence the drain going there.
In water gardening tangential returns are often ignored. But without something pushing stuff to the drain they're pretty much worthless. Most people think gravity moves stuff toward drains and so think sloped sides are the key. But they're wrong. Sloped sides only work if you're trying to remove marbles or golfballs. The stuff we want to remove is almost buoyant neutral, gravity has virtually no effect.
Waterfall catch basin:
thanks for the advice. I hadn't planned on flooring the bottom as we have a sand base here. I was just going to shovel sand in, level it and construct the sides out of plywood (treated of course). I could dig a trench for the bottom drain plumbing and put a drain in the center, but I'm afraid of settling unless I really pack the sand down well. Hopefully, the weight of the water pressing down on the liner will keep everything in place if I do this.
Oh...you mean the pond is or will be through the porch floor, not setting on the porch floor? If that's the case I would trench, no question. Settling shouldn't be an issue assuming a EPDM liner. You don't want to allow sand to be eroded from underneath, that would be bad. A good foundation solves that. But the pipe will settle along with everything else and the connection to EPDM is very flexible. Common practice with professional pond builders is to encase the pipe in concrete where it connects to the liner so there's no difference in settling right at the connection and to keep the connection from moving.
I know you're using treated plywood which is fine, but it can have a limited life. It resists rot, not impervious. Concrete block is way, way cheaper and easier imo. I've built both ways. I thought wood would be faster...I was wrong. I thought treated wood would last longer...I was wrong.
Here's a wood pond in the background and a concrete block in the foreground. I torn down the wood ponds after a few years and saw the rot that wasn't visible from the outside. It surprised me.
I know you're using treated plywood which is fine, but it can have a limited life. It resists rot, not impervious. Concrete block is way, way cheaper and easier imo. I've built both ways. I thought wood would be faster...I was wrong. I thought treated wood would last longer...I was wrong.
Here's a wood pond in the background and a concrete block in the foreground. I torn down the wood ponds after a few years and saw the rot that wasn't visible from the outside. It surprised me.
Thanks for the advice but cinder blocks seem a lot more expensive and time consuming to make look nice. Have you ever tried wrapping treated lumber in the pond liner and stapling it on to stop water intrusion? The deck on our older home had a hot tub that we removed and heavy duty polyethylene was wrapped around the floor joists under it. I was there ten years when I exposed them and they were as solid as a rock. If the treated lumber was wrapped with pond liner so it wasn't exposed to moisture, then you could heap soil up along the sides and landscape it. Would this work?
I agree...seemed more expensive and time consuming to me also...that's why I built with wood first. I changed my mind only after building both ways.
However, your structure is probably pretty small I assume. Wood works a lot better the smaller the pond. A 4x4 in a large pond is like a toothpick but in a small pond is beefy.
The cost comparison is pretty easy to do. I am comparing apples to apples. I think it can be cheaper to build with wood depending on pond size. But if the comparison includes the requirement that the pond lasts 5, 10, 20 years I think concrete gets cheaper. For the initial build I think it's about equal, but I haven't done the comparison in many years.
I don't know if the deck joist was pressure treated, but would say a treated deck joist should have no rot after 10 years when not wrapped in plastic. Not sure I'd give the plastic the credit.
In general I personally wouldn't wrap wood in any plastic, or tar, or even latex type paint. The plastic would kept the wood damp. I do put EPDM on top of wood beams to shed water and protect from UV, but not a complete wrap. But I don't have any experience with doing that type of thing below grade so I know nothing. I'd check with the manufacturer and do exactly what they say. There's been hundreds of years of human experience with wood and soil contact. And the manufacturers really do a lot of testing and do want the best performance. There are different treatment and would make sure I used wood rated for soil contact. If a wood could be used in soil the manufacturer would tout it and make more money. If not rated you know it'll rot in soil because they tested it and it failed.
However, your structure is probably pretty small I assume. Wood works a lot better the smaller the pond. A 4x4 in a large pond is like a toothpick but in a small pond is beefy.
The cost comparison is pretty easy to do. I am comparing apples to apples. I think it can be cheaper to build with wood depending on pond size. But if the comparison includes the requirement that the pond lasts 5, 10, 20 years I think concrete gets cheaper. For the initial build I think it's about equal, but I haven't done the comparison in many years.
I don't know if the deck joist was pressure treated, but would say a treated deck joist should have no rot after 10 years when not wrapped in plastic. Not sure I'd give the plastic the credit.
In general I personally wouldn't wrap wood in any plastic, or tar, or even latex type paint. The plastic would kept the wood damp. I do put EPDM on top of wood beams to shed water and protect from UV, but not a complete wrap. But I don't have any experience with doing that type of thing below grade so I know nothing. I'd check with the manufacturer and do exactly what they say. There's been hundreds of years of human experience with wood and soil contact. And the manufacturers really do a lot of testing and do want the best performance. There are different treatment and would make sure I used wood rated for soil contact. If a wood could be used in soil the manufacturer would tout it and make more money. If not rated you know it'll rot in soil because they tested it and it failed.
Back filling with drain rock instead of soil would probably be the best choice. Also, if the porch is covered, and the soil never gets wet, would be a huge plus.
You can also use a draining type plastic padding between the liner and wood on the inside of the pond. I don't think it helps a great deal, but is better than liner right up against wood. I used a woven landscape fabric. I still had rot where there was moisture but above that the wood looked like the day installed. But that might have been just as true without the fabric.
You can also use a draining type plastic padding between the liner and wood on the inside of the pond. I don't think it helps a great deal, but is better than liner right up against wood. I used a woven landscape fabric. I still had rot where there was moisture but above that the wood looked like the day installed. But that might have been just as true without the fabric.