The Construction of my Ponds - Page 7 - The Final State

How it all began     First Rebuild      Second Rebuild (1)      Second Rebuild (2)      Second Rebuild (3)      Third Rebuild

Well, as you can imagine if you have read the whole of my site, my ponds are never likely to remain unchanged for long with me and so they have changed again. It all started when a couple of my sisters visited in the summer of 2010 for the Bourne Festival and declared that the garden didn't seem to be as big as they remembered. At first we just laughed it off but after they had gone back home, we began to think that they might have a point and tried to work out what the difference was. Eventually, we realised that it was because the hazel tree had grown so big and that when looking down the garden from the house, it formed the right of arc of vision instead of the garden fence. As a result, our garden looked only half its size to occasional observers and once we had seen the garden as they had, it was obvious that we had to do something about it. It was time for a drink.

I have no sentimentality for plants in my garden and if they are not doing what I want of them, they go. The obvious solution was to remove the tree but perhaps we should just cut it back quite hard. An hour later, we just had a stump left and once we had cleared away all the branches, our garden looked so much bigger that we knew that the tree had to go. However, we now had another problem. Without the tree above it, the "promontary" with the bubble fountain looked far too big for the pond and when "Management" asked if we could remove that as well, the afternoon really got interesting. The thing is that once you start with such a radical change, the "what ifs" keep coming and by the end of an increasingly happy afternoon, we had a plan. Not only were we going to get rid of the promontary but we were also going to take the opportunity to completely re-design the bottom of our garden and also to rebuild the top pond so that the waterfall would be more central and therefore more visible from the bottom of the garden where we intended to move our swing chair. We also decided to think about redesigning the top pond as well once the rest of the work had been completed.

In theory, removing the promontary shouldn't be a problem because the liner goes under the fountain and all the way to the tree so in terms of its length, if it is long enough to go up the side and then along, it should be long enough to go along the bottom of the pond and then up the side. However, I had to be careful not to damage it as I removed all the concrete, pebbles and blocks that were on top of it. I thought that the best way would be to dig out underneath the liner so that when I started to break up the top, the liner would be loose and would be less likely to get ripped. Digging out the root of the hazel tree gave me the start point for tunnelling and soon I was down below the water level albeit not yet under the liner. Although I had dug out the tree root, there were so many capilary roots that it was extremely slow work and my access position was not good. I was developing renewed respect for the war-time POWs who had dug their escape tunnels using spoons and their bare hands. I had an array of decent quality garden tools at my disposal and still it was extremely difficult. I did think of leaving a shallow area with a bed of grasses which might be quite good for the fish to mate in but I felt that I had no choice but to go down to the full depth of the pond because otherwise, I would be creating an ideal hunting position for my old enemy the heron. Because of that, this is what I was now having to remove with only that hole for access,

I thought that digging out the earth would be the trickiest bit but I was wrong. Once I was in a position to be able to loosen the liner from the underside of the concrete under the fountain pebbles, I found that it was stuck fast because the cement had found its way into folds in the liner and had set as hard as the rest of it. Although some parts of it would respond to gentle pulling, the majority of it would not move without ripping if I simply aplied more force. In the end, I had to bite the bullit and use the big hammer and cold chisel. By trying to crack the cement at what looked like a critical point, I hoped to be able to remove the cement from the liner rather than the other way around. I don't know if you've tried to be delicate with a 4lb club hammer but it is not easy and more than once, I thought I had overdone it. However, eventually, I managed to free up the top of the liner and I lowered the water level so that I could remove the blocks around the side of the pond. My plan then was to dig out as much earth as I could but leaving an earth wall at the sides which I could then remove when I was ready. Working under the liner was hot, cramped and very very slow but eventually, I got to the stage where I could start to remove the wall I had left. Conscious that as soon as I removed the wall, water pressure would try to force the liner into the hole, I used some heavy duty aluminium cloche hoops to hold up the liner as I worked at the walls. This was the most delicate stage as my trowel would be at its closest to the liner so my method was to push my hand between the wall and the liner and then to use the trowel into my hand. That way, I should feel the blade before the liner did and thereby prevent any damage. After I had removed about half the thickness of the wall this way, I decided to change to an older trowel which was really blunt and so less likely to damage the liner. So I climbed out of the hole and I was just going into my shed when I heard a strange sound behind me and I looked around to see the hoops falling away from the liner and the water pouring into the hole.

There was nothing else to do but reduce the level of the pond still further until I could raise the liner again to complete the job. By that time, I only had about 20cm at the deepest part of the pond and the only way to hold the liner up to complete the job was to get completely under it so that it was resting on my back whilst I completed the removal of the remaining art of the earth wall. As it turned out, that was the best thing I could have done because it was only from there that I noticed a couple of pinholes of light that shouldn't have been where they were. Somehow, despite being as careful as I could, there were 2 punctures in the liner in a place that would be under water once the liner was in its final position. Luckily, I live only a few miles from Water Gardening Direct at Frognall so after a short drive, I had a tube of ****, which they assured me would set even under water, and affected a repair. The only way to test that was to fill the pond so at last my fish could swim about more comfortably. A check of the earth under the liner the next morning showed no sign of leakage so I lowered the pond again just far enough to rebuild the block wall along the side and along the bottom where I had redesigned the pond to allow an extension of the lawn up to the edge of the pond.

Once the main pond was completed, I started to work on the top pond. That was an awful lot harder that I had expected because when I build things, they are generally meant to stay in situ for ever and the job of lifting the slabs around the pond without breaking them was particularly hard. Even using a big SDS drill with a chisel bit, it took ages to break the seal between slabs and concrete and I didn't get them all up intact. Still, eventually I had the job done and then it was time to rebuild. I had decided to use a metal blade for the waterfall rather than slabs so that I could get a really smooth looking sheet of water falling into the water. I had seen these in garden centres and they were much quieter than a normal waterfall which meant that I could get a much higher fall which in turn should give me much more oxygenation for the bottom pond. A small amount of research on the Internet showed that for the volume of water that I would have flowing over the blade, the waterfall needed to be about 600mm to 700mm wide. A local firm provided a 200mm x 800mm sheet of 1.2mm stainless steel for just 20 so all I had to do was get it in place. The size was such that I could have blocks at each side to direct water over the blade and I could have an overhang of at least 5cm above the wall. In order to prevent the corners from damaging the liner, I stripped the outer cover of some electrical lead and split it lengthways. Then I taped it over the ends of the blade. The majority of it would be covered by the blocks and cement so I wasn't too worried what it looked like at that stage.

The trickiest part of the whole rebuild of the top pond was getting the new liner to fit behind the block wall of the bottom pond but in front of the bottom pond liner so that if I had any water seeping under the blade, it would still end up into the pond and not leak out to the sides. Eventualy, that was achieved but not without a huge amount of trial and error and a lot of patience on my part. I fitted the blade horizontally across the width of the fall and at a slope of about 10 degrees down at the front (ie bottom pond side) so that the water would be encouraged to form the sheet that we were hoping for. The first time I fill a top pond and wait for the water to build to the level of the waterfall is always full of anticipation and this was worse that ever because if I hadn't got it right, it would be very obvious to everyone. We had filled the pond to just lower than the lip the previous evening so we just used a garden hose to fill the remaining inch so that we could see the blade forming in slow time. It was immediately obvious that I hadn't got it quite right as the water started to trickle over the right hand side of the waterfall at first rather than build up behind the blade until the meniscus was breached. Then another trickle started and soon we had a series of trickles but no sheet. However, now was the time to switch on the pump and to have another 8,500 litres per hour flow. Immediately, the trickles began to join into a flow and then suddenly the sheet formed as the flow built up to its full amount and it was exactly what we had hoped for. The fish noticed straight away and all came to play in the bubbles.

That happened about 2 months ago now and already, the increased moisture on the wall behind the fall is providing an ideal location for moss to start growing and I expect that within a couple of seasons, it will look as though its been there for a very long time. We would love to have fish in the top pond as well but it would be too inviting for the heron so we will leave it for the plants. The wires that I have around the main pond need to be replaced now and this time, I'll be using a former for the supports so that I can get them all the same and I intend to paint them black which should help them blend into the background. For the same reason, I'll be using dark green plastic-coated wire. (Pictures coming in the spring.) The only problem that I have found is that because I had to empty out most of the water from the pond, any remaining effects of the Cloverleaf Blanket Answer have been lost and I have noticed an increase in the formation of blanket weed, especially around the waterfall because of its increased oxygenation. I put in some more Cloverleaf but by then, the water temperature was dropping and its effects were reduced. Hopefully, as we go into the winter, the remaining blanket weed will die off and once I dose the pond properly in the spring when the water warms up, all will be well once more.

The winter of 2010 was one of the better ones in the UK and it wasn't long before I got some nice pictures of the pond during the big freeze.

Third Rebuild   Top