Well, if the soil is clay, it just keeps it's shape no matter what. In Florida, the soil is sandy, even where I lived in the Northern part of Central Florida. Some used some type of retaining wall and some didn't. It really just depends on your soil or your tastes.

What pondmaninal said. . . Clay soil is GREAT for carving a pond into it. I get into the pond once a year and walk on shelves and bottom and everything stays in place.

Do you ponders *never* walk into your pond?

Nope, never. Even central Florida undisturbed sand is very compacted.

{{gwi:223068}}

Unlikely?

Dianne

I have a 2500 gallon pond, no retaining walls, and no shelves. I only enter my pond if there is something unexpected that needs attention. You don't need to get in the pond to do aquatic maintenance. All of my pruning and rearranging is done from the edge. I did have one shelf one time that I used as a step to get in and out, and no the liner did not move when I stepped down. The soil was already compacted from the weight of the water, so that did not affect the shape or stability of the shelf. I removed it during an upgrade.

Nope, there is no shifting or sifting or soil under the liner. Again, the weight of the water holds it in place. Water is very heavy.

We have sandy loam and the shelves you talk about. I get in it all the time to do stuff. Our soil compacts to almost as solid as concrete though and we did not build our shelves, (which would have caused loose dirt) we cut them out of the sub soil. So the shelves are very compacted and have been for a very long time before we started digging. With that and the weight of the water I suspect there will be no movement.

I went into my pond once after i got it started, I ended up doing the splits when I didn't intend to. I do all maintainece from the sides for the last 3 years. I did walk on my shelves when it was very clean and new and had no problems with stability, of course I wouldn't step on the every edge. Plan to make it reachable from the sides, I use a rake. You can search my name and find the construction pictures in the gallery.

My soil is clay and I've never once set foot in any of my ponds. My fish pond was built in 1996. I use a 12' long 2 x 12 plank across the widest section to reach whatever I need to reach.

Hi
I think the "ideal" plan for a pond is to locate it where it can be approached from all sides with no shelves since it's sooo easy to bring the pots up to the proper depth this allows you to place the plants anywhere and change at anytime. A flat bottom allows for the greatest volume of water, allows placing the pots anywhere as well as the inevitable vacuuming MUCH easier. Of all the "ponds " I've built over the years my favorite has been an 18 inch above ground that is also 20 inches below ground. Interestingly it was built to store rainwater not as a water garden lol
It evolved into both a water garden and a fish pond ,since it is piped to collect rainwater from the roof it becomes an automatic purge system. Does about 80 percent of the maintenence eliminating water changes except when it doesn't rain.
This pond has been running since 82 and made of stacked 4x4'with a fiberglass liner with no problems EXCEPT for strangler fig which finds the space between the liner and 4x4 and IDEAL place to grow . Anyway my point was that i wouldn't build a pond that required getting into it to do maintenece in the first place with no shelves . gary

Everyone thank you so much for your input. The soil in my area is mostly clay. It is good to know that I do not actually need to go into the pond to do the general aquatic plant-life upkeep, and that even if I do go into the pond, I need not worry about shifting soil.

My current plan (which changes all the time...) is to have a pond that extends both above ground and below grade. The pond will be 4 feet below grade, and 1.5 feet above grade. This should give me a total depth of 5.5 feet, which should be sufficient for overwintering koi in my pond, I hope.

The plant shelves will be at grade level and will be 18 inches wide. There will be a 2 feet tall retaining wall surrounding the pond, with the pond water level extending to 18 inches above grade.

I might end up making the retaining wall higher... the objective being to keep pre-school kiddies from accidentally falling into the pond.

I have lovely sandy loan soil - great for gardens but bad for pond walls. My first pond the sides did break down. Now the sides are all covered in concrete reinforced with plastic chicken wire. It's an inch - 2 inches thick. By the stepping stones the walls are thicker because I knew there would be lots of foot traffic there. There is a big concrete slab under the stepping stones. All the edges have more concrete. So far, it's working!
I climb into my pond to clean up the water lilies. Sometimes I climb in just to play with the fish and frogs. Even if you don't think you will go into your pond, plan a couple places for "steps" just in case. A nice flat step and a post or big rock to hang onto for safety.

frugalgardener, thanks for your input. I just consulted a few books for building koi ponds, and they all seem to recommend reinforcing the sides with concrete and chicken wire like you did (this is optional). I think I will err on the side of caution and do just that. I know I will have to enter the pond twice a year to move hardy waterlilies between the shelves and the deep region, so I think it would be beneficial to integrate a foot traffic zone like you did. I really don't want to have to drain a pond to repair the liner if I can at all avoid it.