Yesterday I did the finishing construction touches on my pond island project: adding some bracing, the pond liner to hold the dirt, and some bumpers.

I started by added some bracing boards to help prevent the pond liner from sagging under the weight of the dirt. The liner is pretty stiff, and will be supported by the water, but a bit of extra support can’t hurt:

Another reason for that was to prevent the buoyancy buckets from pushing up into the liner:

Plus I attached a pipe strap to support the buckets, to keep them off the ground during transport to the pond; again, the water will support them once in the pond:

Here’s the last look at the island structure before adding the liner:

Next I added the pond liner, using some scraps I had on hand. (Other than the buoyancy buckets and pipes, all of the materials for this project are things I already had spare; I always order extras when getting lumber etc for projects.)

There wasn’t a piece big enough to cover the whole island, so I added two overlapping pieces. Here’s the first, temporarily weighed down with heavy buckets to help position and shape it:

The liner is attached to the frame using screws and washers:

Here’s the whole island with both pieces of liner installed:

(The liner is wet because it was sitting on the driveway while constructing the rest.)

I didn’t bother trimming the liner on the angles, I just tucked it behind the lower platforms, which helps fill the gap between the frame and platform, too:

Lastly, I slit pool noodles and added them as bumpers on the lower platforms, to prevent damage to the pond if the island floats free and hits a side:

I will anchor it when installing it, but doesn’t hurt to be cautious. The noodles might provide some buoyancy benefit, though will probably become waterlogged over time.

Like the liner, the noodles are attached with screws and washers (small and larger washers on each):

That completes the construction of the island! 🎉

The next step will be to take it to the pond. It’s already on the cart, so it shouldn’t be too hard to get it there. I may need Jenn’s help in getting it from the cart into the water without damaging anything. Though one interesting notion could be to take the cart into the pond, and float it off. Either way, I’ll be wading in the pond.

I’ll be very interested to see at what level it floats. Once it is, I’ll try adding water to weigh it down, if it doesn’t all leak out between the two liner layers, then add dirt and grasses. I’ll also position it and anchor it to some cinderblocks on the pond floor.

The next update should be super exciting; stay tuned!

Only a little time to work on the duck island project yesterday (Weekend Wednesday). I spent about a third of the time planning the previously-mentioned upper platform, about a third changing my mind about the position of the pipes, obviating that platform, and a third moving the pipes. Read on for details.

Last time I wrote about the buoyancy of the island, and adding the ring of 4 inch pipes inside the frame as part of that. The plan was to add the dirt-containing pond liner over the top of the pipes, then build a third platform level on top of that. So I started by laying out some scraps of wood to prototype the platform:

Another angle:

But on further reflection, I thought that the position of the pipes was suboptimal… or not optimal for submarine buoyancy. As mentioned last time, I wanted the water level to be about halfway up the pipes, which seems a waste of the buoyancy potential of them… and with the expected weight of the island and dirt, I need every bit of buoyancy.

So I decided that the ring of pipes should be below the 2x4s, not above, i.e. underneath the island instead of within the surrounding frame. Which also means I probably won’t need the upper platform I’d just prototyped; the dirt can just go to the edge of the frame, as I’d originally envisioned.

Having decided that, I unscrewed the metal hanger straps and carefully removed the pipes:

I then lifted the island onto an edge, so I could access the bottom:

Then mounted the pipes underneath:

A closer view:

A pipe strap:

I also mounted a couple of the buckets, attaching them with heavy-duty fence staples:

Maybe the last view of underneath the island, with the pipes and a couple of buckets:

I didn’t attach the other two buckets, as they would get in the way of the cart. I can just tuck the buckets under there while installing; they’ll be contained by the wood and pipes.

Back down on to the cart:

A closeup of a bucket and the pipes below the frame; the bucket will be lower down later; it’s just resting against the pipe for now:

The current state of the island:

So not as much progress as I’d hoped, but that’s fine; this was a worthwhile tweak.

Next time, hopefully, I’ll add the pond liner. But before that, I’m thinking I’ll add a few 1×2 strips to help support the liner, to prevent sagging.

Our ducks spend a lot of time on the banks of our pond, or swimming around the pond. Being in the pond is safer for them at night, being less accessible to predators.

I have added several upturned pots in the pond as mini islands for them to rest on, as additional options, but there aren’t enough for everyone.

So I recently had the idea of using an old dinghy (that we inherited with the property) as an island.

Here’s the old boat:

I dragged it to the pond:

Then waded in the pond, flipped it over, and pushed out most of the air (the boat has a big hole in the bow), to make a larger island, wedged on top of one of the pots:

However, that isn’t ideal either, as (a) the ducks seem to be freaked out by it, not wanting to go near it, (b) it’s kinda ugly, and (c) it doesn’t seem great for roosting or nesting.

So I decided to build a wooden island, with a thin layer of dirt and grasses, contained by some spare pond liner. And to make it a bit more island-like, I thought I’d make it an octagonal shape.

The first step was to sketch various sizes to determine a good size; big enough to be useful, but not too big, and considering materials (cutting 8 foot boards into various lengths efficiently). I sketched it in the excellent Linea Sketch iPad app:

I decided that an octagon 6 feet across would be ideal, with some platforms around water level to make it easier to get on and off. Here is the design I came up with:

Here is a GIF time-lapse of my drawing (a fun new feature of Linea Sketch):

I surveyed the wood I had on hand, and started to construct it:

The edges are 6×1 boards, screwed into blocks; here I’m laying out the pieces:

Below the edges are 8’ 2×4 boards to help hold the shape and support it, with bits sticking out beyond the edges for the water-level platforms (this is upside-down):

That’s where I’m at currently. On Sunday I’ll add the platforms.

My original concept was to add legs, so this would sit on the pond floor to support the weight of the wood and dirt. But I’m now planning to make it a floating island. Floating would have the advantages of rising and falling with the pond water level (which can vary about 10 inches throughout the year), and perhaps be movable for maintenance. But it also has some complexity of getting it to float at the right level, and anchoring it in position.

So I need to figure out how to add sufficient buoyancy. There are complex formulas for that, but that’s beyond me, so I’ll probably just add a bunch of foam pool noodles, and/or closed pipes, and hope for the best. If anyone has any advice on this, I’d welcome it!