Risk of shelf collapse from rain?

[combatwombat]

Got most of the hole dug for the new pond yesterday. Haven’t ordered a liner yet because I wasn’t certain on exact dimensions until we started digging and I was worried we’d hit something during the dig and I’d have to change plans on the fly.

Soil ended up a little softer than I expected. Pretty loamy. Not much clay. Great drainage, though!

Will probably be at least a week before the liner is here and I ha e rain scheduled for tomorrow.

Am I going to lose my shelves? Thinking about getting my underlayment and getting it in there today to help keep rain and runoff from washing the shelves out.

Think that will work? How difficult is it to reconstruct a shelf if I get a collapse?

 

[brokensword]

if you have some sort of covering (box store tarp), I'd use it. I'd rather NOT reconstruct shelves, esp if you don't have clay. Worst case scenario, you could use solid concrete slabs and build it up, but I'd rather have one solid 'box' for the pond. Keep the rain off and contain it within the tarp, even pump it out (as you'll have to anyway, should you get a lot of rain before your liner arrives). I actually installed my expansion liner IN THE RAIN. It was a pita, but I have clay and it would have pooled (to be pumped out as I'd done earlier) anyway.

 

[combatwombat]

@brokensword: Gotta be a pretty massive tarp. Will go look for one anyway. Thinking this through again, the pond shelves will be rocked in from bottom to top, so maybe not the end of the world if I get a little collapse.

Dig out collapses, insert liner, build rock wall where you want shelf to be, fold liner back, backfill against wall and compact, fold liner back into place, continue.

Might work?

 

[combatwombat]

Thinking about this more, what I'll do is try to find some woven geotextile fabric today. That stuff is not very porous, and I just need to shed rain water that falls over the hole to the bottom of the hole. It's quite sandy at the bottom, so I think if I just keep water off the shelves, I should be okay, and the water that ends up at the bottom of the hole should absorb pretty quickly.

I think non-woven fabric is generally recommended under EPDM, but I will be using an RPE liner, and since my soil is very soft with no sharp stone, I will skip the underlayment and then reuse this woven fabric over the liner when I rock the pond in later.

And I think I already have what I need onsite to direct any runoff away from the excavation. Built a little berm around the whole pond and will temporarily redirect a downspout.

Thanks for letting me think out loud here. Now it's just me in a race against the rain. Wish me luck.

 

[TheFishGuy]

Thinking about this more, what I'll do is try to find some woven geotextile fabric today. That stuff is not very porous, and I just need to shed rain water that falls over the hole to the bottom of the hole. It's quite sandy at the bottom, so I think if I just keep water off the shelves, I should be okay, and the water that ends up at the bottom of the hole should absorb pretty quickly.

I think non-woven fabric is generally recommended under EPDM, but I will be using an RPE liner, and since my soil is very soft with no sharp stone, I will skip the underlayment and then reuse this woven fabric over the liner when I rock the pond in later.

And I think I already have what I need onsite to direct any runoff away from the excavation. Built a little berm around the whole pond and will temporarily redirect a downspout.

Thanks for letting me think out loud here. Now it's just me in a race against the rain. Wish me luck.

Sound a good plan!
I just used that heavy duty weed barrier for underpayment in my ponds, never had any problems.

luck!

 

[Lisak1]

I just used that heavy duty weed barrier for underpayment in my ponds, never had any problems.

Well, just a slight caveat that this advice is coming from a 12 year old. Who's previous pond was running for how long? Careful how you dish out advice @TheFishGuy . I don't know what you mean by "heavy duty weed barrier" but "never had any problems" kind of indicates at least more than a few minutes of experience with a product.

 

[JamieB]

I’ve got loamy soil here too, lovely flood plain area, and this portion just sits high enough to require record breaking flooding to get to my pond. I dug out my pond last fall, and let nature do her worst to the shelves. Very little damage. In fact, I’ve done more damage trying to fine tune them, than nature did, even a few pretty good rains. My pond would be done except mice chewed holes in my liner, and I haven’t gotten around to fixing that.

 

[TheFishGuy]

Well, just a slight caveat that this advice is coming from a 12 year old. Who's previous pond was running for how long? Careful how you dish out advice @TheFishGuy . I don't know what you mean by "heavy duty weed barrier" but "never had any problems" kind of indicates at least more than a few minutes of experience with a product.

I try to not dish out uneducated advice, of course sometimes I do make mistakes as that is only human, but this time I would not call that advice a mistake.

personally I have only had a pond running for two years max, but the guy who I sometimes mention with the crazy pond backyard was actually the one who advised me to not spend exces money on underlay, and go with something like weed barrier.

he used weed barrier in two of his four current ponds, and has had them running for around 8 years, again no problems. One of them with 6 tons of rock in it, so I trust he is confident in that piece of advice.

by heavy duty, I just mean not the wimpy gray stuff that constantly gets holes in it, I mean the black stuff with long strands of plasticy material woven together, just noting that I do not nor have heard of any experience with the lesser of the two weed barriers.

 

[combatwombat]

@JamieB: That's good to hear. I'll worry a bit less about it for now. I seem to be causing more problems just stepping around in it. Imagine it will be fine once I rock the whole pond in. Of course. The weight of me + a bunch of boulders... I can see a lot more collapses happening between the beginning and ending of that process.

 

[Lisak1]

@TheFishGuy - lots of people will give all kinds of advice based on their own personal experience... but that's just anecdotal evidence, which only goes so far. My advice comes from one pond, but a lifetime of OTHER experiences, many of them costly and painful. I would personally never skimp on the very first thing that goes in a pond, because if it fails you're gonna have to take it all apart and start from scratch. Some people use carpet scraps or old blankets or even old newspaper as underlay and never have a problem. But I know I wouldn't be able to sleep at night wondering if I will regret saving a few hundred dollars on a pond that cost me thousands and more importantly hours of back breaking work. Pros use the products they do for a reason - they don't want to take a chance that the product will fail. And again - that's not pond experience - that's life experience.

And it's not the weight of the rocks that are the concern - it's what's underneath the underlay that will cause issues. I mean you know from aquarium experience how heavy water is - just the water in the pond will weigh tons without a single rock in it. And some people may need to be concerned about burrowing rodents, and may need something even stronger than underlay. Every situation is different.

You do a great job of being positive and supportive and your knowledge far exceeds your age. But I would say the same to someone who my age who'e had a short window of experience - saying "I've never had a problem" means a lot more if you follow up with "in the two years since I built my pond". Just frame your advice within the window of your experience.

 

[addy1]

I used carpet pad, but then again, our dirt is rocks with a bit of dirt holding them together. The rocks are not neat rocks but shale with a bit of granite tossed in. Pull one out another appears.

The liner I bought I was told I did not even need to use underlay, but with our rocks I did. My big pond is not epdm

 

[Mmathis]

I wouldn’t use weed barrier in place of an underpayment — you can’t compare the two. I experiment with a lot of things, but I don’t play around with the liner and underlayment! Like @Lisak1 said, there’s too much at stake!

 

[TheFishGuy]

@TheFishGuy - lots of people will give all kinds of advice based on their own personal experience... but that's just anecdotal evidence, which only goes so far. My advice comes from one pond, but a lifetime of OTHER experiences, many of them costly and painful. I would personally never skimp on the very first thing that goes in a pond, because if it fails you're gonna have to take it all apart and start from scratch. Some people use carpet scraps or old blankets or even old newspaper as underlay and never have a problem. But I know I wouldn't be able to sleep at night wondering if I will regret saving a few hundred dollars on a pond that cost me thousands and more importantly hours of back breaking work. Pros use the products they do for a reason - they don't want to take a chance that the product will fail. And again - that's not pond experience - that's life experience.

And it's not the weight of the rocks that are the concern - it's what's underneath the underlay that will cause issues. I mean you know from aquarium experience how heavy water is - just the water in the pond will weigh tons without a single rock in it. And some people may need to be concerned about burrowing rodents, and may need something even stronger than underlay. Every situation is different.

You do a great job of being positive and supportive and your knowledge far exceeds your age. But I would say the same to someone who my age who'e had a short window of experience - saying "I've never had a problem" means a lot more if you follow up with "in the two years since I built my pond". Just frame your advice within the window of your experience.

Makes sense,

I think I was just trying to give an option I’d say they were opposed to spending that much money,

I honestly probably should have used real underlay, but we will se how it goes with my new pond being 8 feet away from a tree.....

 

[TheFishGuy]

I wouldn’t use weed barrier in place of an underpayment — you can’t compare the two. I experiment with a lot of things, but I don’t play around with the liner and underlayment! Like @Lisak1 said, there’s too much at stake!

Welp, I will hope it doesn’t fail me this time!

For me it is fine cause I really do know I will be ripping it out in a couple of years anyway.

 

[Lisak1]

I think I was just trying to give an option I’d say they were opposed to spending that much money,

I think the only way you really save money when building a pond is to provide your own labor. We were able to get great pricing on all the components for our pond build by working out a package deal with a local landscaper. He gave us his contractor pricing because we were using him for rocks and he did some excavating for us. So there are ways to save, but I wouldn't recommend doing it by improvisation.