In Trouble with Excavation

[WaterLilly]

Hi ,

I started another thread because i have utterly different questions. These are real urgent. Because tomorrow this excavation has to be done.

Today i started the excavation but i got lots of troubles. We are using an excavator so we can't go into little details. You can't dig a 10 inch hole with a shovel in this surface.


Question 1 : Look at the pond plan i drew. As you see the deep spot requires significantly higher amount of EPDM in length. Do you think i am in trouble? This is not my pond plan. I exaggerated a bit.

Question 2 : See the pictures. Rocks are everywhere. And no way to just collect them by hand. Do you think i will be OK with a thick geotextile or do i need more than this?

Question 3 : As you see it is all rocks and sometimes i see a rock with fractures which might tend to fall. Actually they are everywhere. Do you think it might be a problem after the water is filled?

Question 4: Do i need to compact soil? How important is it? I can't find a non electric compactor anywhere. Anything else i can use? Maybe i should get a rock and start punching the soil.

Question 5 : Guys on some edges where there is no perimeter, i have very sharp fall downs. It is 9 ft deep right away. Is it dangerous in any ways?


Thanks.

 

[EricV]

I don't know if this is what you were looking for with a "compactor" but here the hardware stores carry them and they are called tampers: http://www.homedepot.com/p/Ames-8-in-x-8-in-Steel-Tamper-2233400/204476033

Obviously the link is not directly helpful, but it gives you an idea about what I used. However, I did not use it on the bottom of the pond since that was already well compacted clay. These things are more useful for compacting loose dirt you might have piled up. They aren't going to do a whole lot to hard dirt.

 

[Timothy]

I will give you my opinion, but please understand, I am a hobbiest, not a professional and these are only my thoughts.
I'm guessing you are in zone 5 or 6?
My first thought is what are your goals? Second, a pond doesn't have to be so deep. The deeper the water, the more expensive in terms of liner, pumps, and equipment.
If it were me and I had those rocks, I would have the back hoe salvage a dozen or so, then have him smooth out the bottom surface as well as he can, then call in fifteen- twenty yards of sand to create a smooth bed for the liner. Re-measure for the correct sized liner and in your case maybe a liner underlayment.

My suggestion at this point is for you to step back and think this through a little. I don't mean to sound harsh, but a little reflection on your goals, and how you intend to achieve them may make a huge difference in a satisfying experience and a nightmare.

 

[moby]

What are you intending to keep in your pond please? It seems overly deep even for koi. They prefer a minimum of three to four feet to overwinter here in the UK? Mine have barely 2.5 ft and thrive.
Can you clarify the dimensions of your pond, width, length and depth (9ft) please?
It's going to take a heck of a lot of water IMHO. 9 ft is dangerous especially if you're 6 ft and can't swim! Will small children have access to it? You can technically drown in a puddle of only 2 inches depth.
My ground is rocky, we used sand to make a smooth base for the thick underLay and the liner to sit on.

 

[Mmathis]

@WaterLilly I responded in your other thread.

 

[Tula]

With a 9 foot depth, I think you'll need to use cement blocks, rebar and cement, otherwise, you risk the walls caving in with just a liner over the dirt.

 

[Mmathis]

With a 9 foot depth, I think you'll need to use cement blocks, rebar and cement, otherwise, you risk the walls caving in with just a liner over the dirt.

Yes, that worries me, as well. And esp since the work has to be done in a hurry which doesn't leave a lot of room for for planning.

 

[Meyer Jordan]

Your overall description is quite vague. I second what has been said above that you have unneeded depth to this pond.
The walls of the pond should be sloped at about 30 degrees to prevent collapse. A added sand base will mask the rock problem at the bottom of the pond. A double layer of geotextile underlayment will protect the walls.

 

[Mmathis]

Here is the link to other thread:https://www.gardenpondforum.com/threads/epdm-liner-question.19939/


@Becky Is there a way you could combine these 2 threads: this current one with the link above? It might avoid some confusion instead of going back & forth.

 

[Big Lou]

I suspect your rocks are actually a form of highly compacted clay, soil mixture. To test my suspicion selection a typical specimen, move it away from your work site. Using a hammer srike on "rock". If object somewhat easily dents, cracks or flakes then soak the material in water to determine if the material smears or becomes smoother. If this test is successful you do not have a true stone layer in your ground.

Btw, I also agree with my comrades as to the excess depth. If you ar building a ver large scale pond or lake then such a depth may be justified. Have you consulted a professional pond building firm or enigneer? Also knowing you location may help us help you.

Welcome and good luck.

 

[WaterLilly]

Guys, i am sorry , i don't have time to tell why i am in such a hurry. But i gotta have this done by tomorrow. It is midnight here(Azerbaijan) and i gotta wake very early. Tomorrow i will read your posts and go finish the job. So i can't write back to all of you. Sorry.

I will make sure there is a slope on that very high walls guys. It is a great idea. I am in 6-7 temperature zone and i will keep some fish from warmer climate. It is not a koi pond. My experience is they live fine but excessive colds are very risky. So i need a very deep pond to make sure they survive.


I coulnd't get a response to my question 1 guys. Please help. It makes me worry.


Eric that tools is what i am looking for but couldn't find it. I will try the excavator to do the compaction.


My pond's dimensions, 25 ft to 25 ft ( it changed a little ) .


I really can't do anything about sharp rocks. Impossible to collect by hand. All i can do is to rely on a thick geotextile.

 

[EricV]

I don't really know the answer to #1. All of us do lesser versions of this. With a three foot deep pond, the amount down the middle is about 6' longer than on the edges and I did not notice a problem. That's one place the folds in the EPDM come from. You should just have more or bigger folds than the average build.

 

[snoozer]

9 foot is a problem if you have anyone or anything that could possible find their way into the pond. It seems to me that you are rushing into this without the planning needed for this project but that may just be my perception. Best of luck to you.

 

[Lisak1]

Guys, i am sorry , i don't have time to tell why i am in such a hurry

I don't know why, but that made me LOL! Nine feet deep? Not a good idea.

 

[Timothy]

I am getting suspicious..............