Planning a pond.

Dear Sir
Can you help me please, this year I am planning to build a Koi pond, this will be about 12' long by 6' wide and 3' deep (overall measurements) with a 9 inch thick concrete block wall.
As for finishing the pond, should I use a pond liner or finish with sand & cement render and paint with a waterproofing agent for ponds.
Could you also suggest a book that I might be able to get hold of that might give a basic plan that I could work from as I still have to work out a filter system and work out what size pump I will need etc.
Also could you advise me about any obvious "Do's & Dont's" when constructing the pond, and how many plants I will need to put in the pond.
If you can advise on any of these matters it will be a great help.
John, Surrey.

Dear John,
Thanks for your e-mail. Deciding what is the best when designing or building a pond is extremely difficult as there are so many ways to do it. The final choice has to be made by the koi-keeper as it does come down to your own preferences, amount of cash available, and also the space in the garden.
12' x 6' is long and narrow, and if there is room in the garden I think 18' x 8' would look much better. If you are really going for a true koi pond then 3 ft is definitely not deep enough, and it should be at least five feet deep.
The nine inch thick wall is fine, and will be ideal for any depth.
Is the pond going to be completely below ground, or are you going to raise it partly above ground? A pond below ground fits in very well with many garden layouts, but can be dangerous if you have young children, or grandchildren.
Finishing the pond is mainly a matter of cost.
The cheapest way is a good quality butyl liner, or other types of rubber that is available. If you purchase it in one large sheet then with a rectangular pond you only have the four folds at the corners. A better alternative is to buy a Boxed liner. This means that you supply the manufacturer with the exact measurements of your pond and they cut and vulcanise the joints so that it hopefully fits in the pond with out any folds which could hold dirt and debris. With a liner you have to use old carpets or something similar to protect the liner from the rough concrete blocks. The ideal way is to use one inch thick polystyrene as this insulates the pond as well as having some give if the fish hits the wall with its nose.
The other way is to have the walls rendered and then use four coats of G4 but this is quite expensive.
The third way is to render the pond and have it fibreglassed, but this can be expensive depending on who does the work. It is important to have someone who has done it before for koi ponds as it is a different technique to that used for boat hulls or car bodies.
There are no books that really deal with the subject as you require, and is one of the reasons that I started this website. None of them give a specific plan as everybody wants something different.
Koi Carp magazine has a lot of useful information. The latest magazine Koi Ponds & Gardens has many photos of ponds that may help you to decide what you want.
Regarding Do's & Dont's I think the Questions and Answers pages on my website answers most of these.
If you have a proper filter system ( not a little box said to filter 6000 gallons) then you don't need plants at all.
The question and answers pages have been made up from genuine questions from koi-keepers that I have helped with advise on how to build their ponds, and they come from various parts of the country.
Look forward to hearing from you again and I will try and hely with any questions you may have. I am trying to put as much information as I can on these pages so hearing from other koi-keepers does help in this respect.
Eric.