The first thing was to draw the outline of the pond on some graph paper.
I knew I wanted it to be about 5000 gallons and 5 ft deep so the surface area had to be 160 sq.ft. I also wanted it in a kidney shape to help the circulation. With the pond shape drawn out on graph paper using a pair of compasses I knew both the radii and position of every curve, (no straight lines anywhere!).
I then measured these out on the grass using a tape measure and sand to give me the real pond outline. Another line of sand was drawn out 12" outside to give me the width of the concrete collar.
The trench was dug about 12" deep and then using a spirit level pegged out the top level of the concrete, about 10" deep.
With the concrete duly mixed and laid it was allowed to set for 3 days. I was amazed at the amount of concrete required, glad I hired the mixer. At less than £15 for the day it was well worth it.
We hired a small digger to get the bulk of the soil out of the pond. Jan drove the digger and I barrowed the soil out to the front of the house. I used a scaffold board under the front of the digger to protect the collar.
We also got carried away with the digger, we were trying to get the bottom pretty level so ended up digging down to the full extent of the digger. Which is why the pond is now 6 ft deep and 6200 gallons.
You can only get so close to the collar with a big digger, so a little digger, my wife Jan, got the walls vertical and the floor sloping. I first had this about 12" but again was told 3" was enough, which has proven to be the case as the bottom of the pond has kept itself very clean. It also gives a gentler slope for the koi to graze along.
Jan kept me busy I can tell you, 35 yds were taken out to the front of the house. I piled the topsoil along the bottom of the garden to use later.
The first 6 yds were taken away with a skip costing £115. My local dealer 'The Koi Waterlife Centre' gave me a great suggestion to use a grab lorry instead. This took 9 yds instead of 6 and cost £95 a load - saved £300.
It was about this time that it became very wet, and just walking around the pond digging out the trenches for the two bottom drains totally destroyed the shedding I had so carefully prepared before.
The drains are 4" pipe so a trench 6"x6" was dug out. The pipes were measured out and assembled dry in situ to make sure everything was OK. Where the pipes were joined I scribed lines across the joints so I knew exactly how to put them back together again. You only get one chance with that glue, and then only seconds to get it right.
The pipework was glued together outside the pond and then laid in the trenches with 1" blocks underneath. Such a relief to actually see them fit.
The tops of the bottom drains were measured to the top of the collar to make sure they were at the same depth.
I dropped our garden roller in the pond to get the sloping right again, good point - it worked really well, bad point - getting the thing out again.
Mixed and laid the concrete, wait another 3 days.
This website started with a
booklet which I made up originally for the help of those members of the BKKS
- South Wales Section who were intending to start building a koi pond, and as the website has expanded more information and articles from other people have been included. This
is for general guidance only, and we do not take any responsibility for problems
that might occur by following these ideas. It is important
that you check out everything in your area, and check on local laws and rules
that may apply.
![[Starting to dig]](img/steve01.jpg)
