New Pond Construction - Questions

[CMP]

Hi there, I am constructing a pond that's 11 ft long, 5.5 ft wide and 3 ft deep. I have finished digging the hole and am looking for help with some topics such as underlay, liner, coping stones and edging. I have googled and googled, and now I come to you guys, the experts

What exactly is the purpose of coping stones? My coping stones are small blocks, 7 inches long, 5 inches wide and 2.5 inches tall. Are these big enough? Do I have to dig them down into the dirt, or can I put them on the edge, put the liner over top, and pile my pink flagstones on top of the liner? So many questions!! Basically just looking for some input on how to proceed with coping stones and edging.

Liner - I bought a liner from Home Depot, it says 15 mls. I see on various posts 45 mls. Is it possible that this "15 mils" is a mistake? Should I return it and buy 45 mil?

CMP Pond

• CMP
• Aug 12, 2018

CMP Pond

CMP Pond

• CMP
• Aug 12, 2018

CMP Pond

CMP Pond

• CMP
• Aug 12, 2018

CMP Pond

CMP Pond

• CMP
• Aug 12, 2018

CMP Pond

 

[sissy]

your coping stones go on top of the liner and they pond needs to be higher than the surrounding ground to keep stuff from washing into the pond .You can put river rock or gravel on the outside part of the coping stones.hd and lowes sell pvc liner and they say 15 mil

 

[mrsclem]

15 mil liner is very thin, may last 5 years. If you can, return it and look for the 45 mil.

 

[GBBUDD]

welcome cmp,
looking at your progress if I am not mistaken it looks like you are digging in clay?
if you took three 5 gallon buckets of water and dumped them into the excavation how long does it take for the water to drain ?
if you suspect it's going to take a long time don't bother . I would strongly suggest you put an under liner drain system. This is a product that's commercially available but any pipe pitched and that you can hook up a pump to or the pressure may push the water up and not your liner. http://www.underwaterwarehouse.com/Multi-Vent-Underliner-System-Pond-Liner-and-Sealants-sc-4192.html

 

[Lisak1]

@GBBUDD - why are you suggesting an under liner drain? Just curious - no evidence of a high water table, so I'm wondering what your concern is here.

 

[sissy]

I have heavy clay and have not had a problem with it perking .When they did my septic system they had to do a perk test and decided the best area for it was the front yard .It perked the best out of 8 test holes .

 

[GBBUDD]

A heavy clay presence will not perk/ drain as sissy is saying as she had to adjust her project.. if water gets under the liner and the clay is very dense which it appears. The water can lift along with create gas pockets and can lift the liner. i found a video of a pond when I was doing homework for my pond and they had the epdm that had bubbled up to the surface . you are right a high water table is even more of a concern but if the water will not drain it is easy to slip a pipe or two below the liner in a trench and have insurance of not having problems after the build. The unobstructed pipe can off the path of least resistance and not allow the water to lift the liner.

 

[Lisak1]

Gotcha. I figured you had a good reason for bringing it into the conversation!

 

[Mmathis]

@GBBUDD I have solid clay soil....and a high water table. And yes, I did have hippo pockets form. But I redid the pond so that the edge, therefore water level is higher than the soil level. That means that the weight and pressure from the water in the pond is greater than what’s in the ground. I think when a lot of folks need French drains is when their ground is sloped, and the water run-off from rain doesn’t have anywhere to go. So it depends on the pond. Even with my high water table, the ground is flat, and the soil does drain pretty well — for clay — and no hippos or backing up have been noted.

 

[GBBUDD]

@GBBUDD I have solid clay soil....and a high water table. And yes, I did have hippo pockets form. But I redid the pond so that the edge, therefore water level is higher than the soil level. That means that the weight and pressure from the water in the pond is greater than what’s in the ground. I think when a lot of folks need French drains is when their ground is sloped, and the water run-off from rain doesn’t have anywhere to go. So it depends on the pond. Even with my high water table, the ground is flat, and the soil does drain pretty well — for clay — and no hippos or backing up have been noted.

You did what we do for drilling large caissons we drill upwards to 15 foot diameter holes and to any depth average being 30 to40 feet deep you increased the head pressure from your pond to the surrounding water table. that's a bit trickier then to simply add a pipe while exposed below the liner. and in Louisiana i'm betting you not only had clay but very lose silt to boot , to go with that high water table. To place a few pipes or even some sand as a trench is a insurance policy to keep one from redoing there hard work. After my first build there are a few things I would have done differently. One to place sand at least 3 or 4 inches over any bottom areas. before I placed up to 2 ton boulders on the rubber . even with compaction and the 8 oz underlayment. But not for water but for the extremely rocky soil I had. but as the pond is almost done it's easy to say now after all the rentals of equipment have been paid for, and the labor urge has lessoned. I won't finish entirely this year.

 

[Mmathis]

@GBBUDD No silt is this part of the state — NW corner, bordering AR and TX. Just gloppy, messy clay!

 

[GBBUDD]

Your lucky that stuff is a challenge and a half