N.Design Studio

 

A Guide to Modern Koi Pond Construction

Concrete Pond Construction

In the United Kingdom it is necessary to have deep ponds that are five to six feet deep because of the long winters that we experience.
Because of this and the fact that straight walls are preferable then heavy construction is necessary to ensure that there is no movement of the structure especially on clay soils.

There are many ponds that have only 4 feet of water, but it is generally considered that to really care for large koi then the deeper ponds are really necessary to develop the correct shape for the larger fish. Most of us do tend to overstock our ponds, especially when our earlier small purchases start to grow.

The structure of the pond described here may seem unnecessary in some more sunny parts of the world, but is the standard used by many enthusiasts in South Wales and many koi-keepers in the UK.

It is assumed that you have now decided on the shape and general design for your pond.
The first step is to get a large sheet of graph paper, and draw out the outline of your garden. When this is done you can then start to draw in the outline of your filters and pond. When you are satisfied with this it is a good idea to go out in the garden and follow the steps shown below.

[Marking out pond]

 In this photo the pond has been marked out, and the two stepping stones show the rough position of the bottom drains. The upright poles are the basic outline for the filters. It is very important that the filter sizes are also checked at this time as if there is not sufficient room then the size of the pond will have to be reduced to ensure that the surface area of the filters are 33 to 50% of the surface area of the pond. Also check out the space required for items such as vortex chambers etc.
It was relatively easy to mark out this pond as it was all straight lines. If you have curves in the pond walls then the laying out of a hose pipe allows you to experiment with the shape until you get it the way you want.

[Digging out pond]

 Digging out of the pond is now well under way. In the right hand corner of the pond can be seen the concrete encased main drain. It had been intended to have the pond raised partly above ground, but as the pond could not be dug any deeper, then it was raised about twelve inches higher than was originally intended. Unfortunately similar problems often occur after the work is started so you must be prepared for this.

[Digging out pond]

 This photo is of another pond which will be six feet deep, and mainly below ground. For this reason the main excavation is seven feet deep to allow for the concrete base. Great care must be taken when dealing with the safety aspect for something as big as this. If it is close to the house, or a boundary wall then always be sure to get professional advice.

TIP. At this stage you should mark out the filter system, but don't start digging until you know the height of the water level of the pond and you know the exact depth required for the base of the filter. If the pond is partly above ground the filter base may not be far below the ground level.

 

This is a good time for us to look at two important items.