First Pond, Driveway Gravel!

[nathanCFD]

Hello, I wanted to ask a question about driveway gravel, of all things! We are digging our first pond, going to use 40 mil liner and underlayment. First 13 inches was clay, now we're into a pile of driveway gravel that looks like it goes down 24 to 30 inches...then more clay. Looks like the homebuilders used the area I picked out for the pond as a spot to rake in all the left-over gravel. Is there any way to continue the project here? I read an article that said to frame in the gravel layer and add quickrite to form a ledge and just continue the pond downward. Can I put a liner over concrete? Any suggestions - the pond either goes right here, or I don't get a pond at all.

 

[IPA]

Is it some gravel mixed into the clay or a layer of mostly gravel? Could the gravel be a septic field or other drainage field?

 

[rubyduby]

Is it some gravel mixed into the clay or a layer of mostly gravel? Could the gravel be a septic field or other drainage field?

great question....

 

[mrsclem]

Sounds like a leaching field for septic system. Don't want to pour concrete over that! You may need to find original plot map to determine if that is what it is.

 

[nathanCFD]

Hey, thanks for the responses! No, it's not a leach field; house is on sewer. It's a 20 X 20 area that's bordered by hardscape on all sides... front porch in front, concrete sidewalk (right), concrete drive (opposite), garage (left). As luck would have it, I found someone with a backhoe and nothing to do last night and they came in and dug the area out for me. The gravel was a 36 inch layer that was full of siding scrap, shingle scrap, pallet straps. Basically when the house was built they used this area as a trash heap apparently, then covered it with a few feet of gravel and then a foot of fill dirt. No wonder I'm getting cracking pavement due to settling, right. So, I guess now I need to get some clean fill dirt and "build back" in my pond walls? Create the ledges? I have a 20 X 20 hole that's 36 inches deep. The pond should be 13 X 14 (my liner is 20 X 25) When you look at the dirt sides, you can see the 30" or so gravel layer on one side, the gravel is only about 4" thick on the opposite sides. I guess I'll pack that with 12 inches of fill dirt? Double up my underlayment - use two layers instead of one? Any thoughts would be appreciated!

 

[IPA]

Glad you got it figured out, and the heavy equipment to boot! I would be asking the same questions. I noticed you stated 40 mil, not 45. Is it Firestone type rubber, HPDE or reinforced whatever the alternative is that isn’t PVC?

 

[nathanCFD]

You're right - it's 45 mil (Aquascape); The underlayment is also Aquascape Non-Woven. I'm going to order more underlayment, I think. Wow, this project has turned into something unexpected!

 

[poconojoe]

Glad you are working it out. Keep us posted and throw up some in-progress photos. We like pictures!
Your experience might help others with similar problems.

 

[j.w]

@nathanCFD
What a lifesaver that backhoe was for ya! Can't hurt to make that underlayment as thick as possible. I used old carpeting w/o tacks, towels, blankets all kinds of soft material to keep mine as safe as possible. The fill dirt over the gravel would not hurt either.

 

[addy1]

Welcome to our forum!

You could dig out the gravel use it to make some neat paths, planting areas.

 

[nathanCFD]

Here's some pics Thanks for feedback

The area

Water Level Graded...sort of.

Ready to start digging down

....and here's were we found the driveway gravel

Backhoe's rule...amazing

bringing dirt BACK into our hole to rebuild the sides and start forming the shelfs

 

[addy1]

Nice!

 

[nathanCFD]

Turns out the Backhoe may have caused more work than it saved. The dirt on the sides collapsed and it started to undermine the pavement. Not good. So, this week, I had to bring in 15 cubic yards or red clay and totally "reform" two sides of the area, tamp them (extensively) and then continue the build! Please don't laugh at our method of rebuilding walls, it's not pretty, but it worked!

We packed, tamped, soaked, etc. Muddy mess but east TN red clay sets up like concrete

 

[nathanCFD]

We're going to try to put down the underlayment and liner this weekend - the Waterfall Filter is 19 inches wide and it's not plumbed. It has a 2 inch bulkhead; I ordered a 3000gph pump with a 2 inch thread and barb attachments and flex pipe. There's no reason to "actually" use rigid PVC is there? I also ordered a pressurized UV canister filter and a smaller pump so we'll have double filtration. I'm planning on laying the liner for the pond first - then building the waterfall/watercourse area on top of that liner - I have a separate liner for the waterfall area that will drape into the pond - which is what i did in the last (and only) other pond I ever did which was 1/1000th smaller than this. Should I tape with seam tape the waterfall liner to the pond liner?

The area that bevels out into the pond is for the waterfall, large sheets of flagstone will stairstep into the pond overlapping that curve, so that will hide the "draped" waterfall liner.

Again, any suggestions or feedback is appreciated!

 

[mrsclem]

Just make sure the edge of the pond is higher than the driveway to prevent runoff. Gas, oil, etc not good for the fish.