Dealing with sandy soil, rain, or caving walls? Here’s a simple solution.
Why This Happens
If you’ve started digging a pond and your beautiful excavation keeps collapsing — don’t panic. It’s common in sandy soil, after heavy rain, or if you’re just dealing with crumbly ground.
This post will walk you through how to build shelves into your pond walls so they hold their shape and still look great.
This question came from a few people in the Ozponds private community — it’s a place where members share builds, ask questions, and help each other out. If you’re interested in joining, it’s included with my Pond Building Blueprint.
Step-by-Step: Building a Pond with Shelves
1. Dig Down to Final Depth
You still want to dig all the way to your target depth — even if the walls keep collapsing.
2. Widen the Hole to Create Sloped Sides
If your soil won’t hold a vertical wall, go wider. Dig gradually sloped sides until they hold.
3. Install Liner + Underlayment
Once you’re happy with the excavation, lay your underlayment and liner as usual.
4. Build the First Rock Shelf
Place a course of rocks to form the first shelf. Then flip the liner and underlayment back over that shelf.
5. Backfill and Compact
Use your excavated soil, sand, or whatever material suits your digging conditions. Backfill behind the liner and tamp it down firmly to prevent future slumping.
6. Lay the Next Course of Rocks
Fold the liner back into place and start building the next shelf on top.
7. Repeat the Process
Flip the liner, backfill, tamp, and build again — as many shelves as you need.
A Note on Groundwater
If you’re dealing with groundwater, now’s the time to take action:
- For minor issues, add pebbles and fill the base with water early.
- For major issues, you may need a drainage system before installing your liner.
What If You Want Sloped Sides Instead?
You can still go that route — just make sure the slope is very gradual.
Too steep, and your gravel or substrate will slide into the bottom over time.
Some ponds with sloped, sand bottoms look spectacular — but that’s not a method I’ve personally used.
Final Thoughts
This method of flipping the liner, building shelves, and compacting as you go is one of the big advantages of using flexible liners for pond builds. It gives you control, helps with tricky soil, and still allows you to make adjustments on the fly.
Want more support while building your pond?
Check out the Ozponds Blueprint — it includes:
✅ All the formulas I use
✅ 24/7 access to Virtual Kev
✅ Entry to our private pond-building community
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