Koi Cymru logo

Pond construction

Alan's pond - The big dig

I will start by introducing myself and a few of my mates who without them this pond would not of been able to be built.
I must also mention my wife who has put up with all the mess and "pondering" if you will pardon the pun for over a year now and also has contributed considerably to the finances of the project.
My name is Alan and I live in a small village near Hull in the east riding of Yorkshire England, I am married to Jill and have two children both boys. I work in the Aerospace industry and have been involved in the keeping of fish and other aquatic life for over 13 years. I say other aquatic life because I keep a reef type aquarium as well as my pond.
I hope through this article that you will be able to construct a pond with some of the grey areas you so often find explained in terms that you can understand and that with a little knowledge you may construct that dream koi pool you have always wanted.
[Starting to dig] All ponds start somewhere and with a little help the garden was dug in the shape the finished pool would resemble.
The ground in my garden is clay and retains its shape well when dug and you can see the sides of the excavation are straight this is because the pool is going to be of block construction on a concrete base. The depth of the pool is 3 feet below ground with a further 2 feet above ground.
I am the one holding the spade with Nick, Chris and Paul from left to right helping.
[Pipe for bottom drain] The pond is dug to the required depth and levelled. The levelling was done by knocking into the ground a series of pegs that had each been levelled with the one nearest to it with a spirit level. This was done all the way around the pond so a plank of wood could be rested on a peg at either side of the pond and a measurement taken to the soil below which was then removed until a equal depth was achieved over the entire pool floor.
As can be seen a channel was dug to accept the bottom drain and a builder's polythene liner put down first to allow the ready mix cement to set more slowly.
Before the addition of concrete a welded steel mesh was placed over the pipe and suspended in what will be the concrete base at least half the depth on pieces of broken concrete paving stone.
[Finished excavation] This picture shows the finished excavation with the bottom drain in place and the steel mesh placed on pieces of broken paving slab so it ends up set in the concrete around about the half depth position adding strength to the base.
The brown pipe in the foreground is the vertical pipe from the bottom drain that will later connect to the filter system.
The round chamber to the left of the drawing is a manhole that I added to take waste pond water away from the filtration system; this will be shown in more detail later.
[Pouring the concrete]

At last the ready mix lorry arrives and after removing my garden fence the lorry was able to reverse down my drive and chute the concrete right where I wanted it.
The mix delivered was a c25 mix which a friend told me was the same as that used for road construction, nevertheless I just told the concrete supplier what job the concrete was for and they obliged.
Chris my mate been in the construction industry tends to go overboard and tell me the whole make up of concrete right down to the slump or runniness of the required mix.
[Moving the concrete]

This picture shows me moving the concrete as it just stayed in a large pile when the mixer dropped it in the hole.
It was hard work moving the concrete around the pond but eventually I did it and levelled the base off by tamping the wet concrete mix with a large plank.
The concrete tended to find it's own level anyway, but if funds could have stretched that far I would have preferred to of hired a vibrating poker as used by builders.
[base completed] Well the finished results look good, the base is flat and the bottom drain is level the pipe in the foreground is the feed to the filter from the bottom drain as mentioned earlier.
The pipework is all solvent welded the cost so far is:
Concrete-£240
Bottom drain-£20
Pipe -free from a mate
4" 90 deg bends £6
I was lucky enough to have free soil removal by a friend called Nigel who made 9 journeys in a tractor and trailer to his fields about 3 miles away for a favour which I later repaid by repairing the said vehicle.
Go to last pond.Return to Pond Index.Go to next pond.
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.
Website Copyright © 1999-2006 Eric W Poingdestre