Need advice on a new pond

[Bob9863]

After getting back from holidays, I spent a while trying to decide where to put the house on the new land, and then design it.
Now that's done I can start planning the pond.
Total are will be 20mX20m at a minimum and I'm considering adding an additional 10m square area.
What I need to initially work out is the depths, I want it shallow at around 1m for the 1st 10m, as I want to stock it with a lot of giant freshwater prawns to fish for. It will also have a 5m deck built over the top of it, I figured that would increase the pond size.
But the back section I'm not sure about, I'm tempted to go down to 3m for 60% of the remaining area, then have the rest at 2m.
I'd provide steps to make little drop off's.
The other idea is to make 60% in the middle 2m tepering off to 3m around most of the pond, back up to around 1m sort of like a spirial.
Or is there something better I should be thinking of?
The pond will be sort of like a rounded triangle.
Also should I put sand in the bottom, or at least over half of it?

The fish I've decided on are,

Tiger fish x2
Golden Dorado x2
Green Mahseer x3
Blue Mahseer x3
peacock bass x1
Mekong catfish x5
Arapaima x1
Catfish (lots)
Tilapia (lots)
Giant snakehead x2
Snakehead (lots)
Giant freshwater prawns (ton's)

I will also put in a heap of native bait fish and small freshwater shrimp.
Its going to be fed from a nearby spring waterfall, so constant fresh crystal clear cool water going in.
After I work this out I will move onto plants and structure.

 

[Midwater]

Sound like a great project.

I don't think you can mix all those fish. The arapaima will get though almost everything. The endangered mekong catfish will get to a certain size and then fade away with too little room (and probably too cold). Even though it is a big pond, with 'tons' of prawns and everything else, your pond could rapidly get septic.

 

[Bob9863]

That's not a problem, I won't keep them to full size, I can arapaima fairly cheap and let them grow to around 150lb, when it gets that big I will give it a local fishing park and get another one.
The Mekong catfish are so incredibly cheap I can grow them up to a decent size, then eat them and replace them. They sell them at the local market for a food fish for ponds for only 50c each.
The main thing that I want to do is to build up a huge amount of small fish and shrimp to create a food chain, I can buy tilapia super cheap by the iso container and get them delivered if I need to supplement their numbers.
But it's the depth is my 1st concern, I want it as deep as I can make it, without going crazy.
But I want to maximise its size by increasing the depth.
Although I avoiding contamination of the water quality will be important, but I have an unlimited amount of water to flush the pond with, I will be running either a 6" pipe to feed it, or make a little artificial stream to keep the fresh water flowing.
I'm not worried about it being to cold as much as I am too hot, in winter or what passes for it anyway in northern thailand I was swimming in the creek just to cool down, and it wasn't cold at all, just cooler then the air.
I'd be interested to know the minimum I'd need of freshwater to flush the pond with to ensure good water quality each day.

 

[SilverArowanaBoi]

After getting back from holidays, I spent a while trying to decide where to put the house on the new land, and then design it.
Now that's done I can start planning the pond.
Total are will be 20mX20m at a minimum and I'm considering adding an additional 10m square area.
What I need to initially work out is the depths, I want it shallow at around 1m for the 1st 10m, as I want to stock it with a lot of giant freshwater prawns to fish for. It will also have a 5m deck built over the top of it, I figured that would increase the pond size.
But the back section I'm not sure about, I'm tempted to go down to 3m for 60% of the remaining area, then have the rest at 2m.
I'd provide steps to make little drop off's.
The other idea is to make 60% in the middle 2m tepering off to 3m around most of the pond, back up to around 1m sort of like a spirial.
Or is there something better I should be thinking of?
The pond will be sort of like a rounded triangle.
Also should I put sand in the bottom, or at least over half of it?

The fish I've decided on are,

Tiger fish x2
Golden Dorado x2
Green Mahseer x3
Blue Mahseer x3
peacock bass x1
Mekong catfish x5
Arapaima x1
Catfish (lots)
Tilapia (lots)
Giant snakehead x2
Snakehead (lots)
Giant freshwater prawns (ton's)

I will also put in a heap of native bait fish and small freshwater shrimp.
Its going to be fed from a nearby spring waterfall, so constant fresh crystal clear cool water going in.
After I work this out I will move onto plants and structure.

As Midwater said, it sounds like a fun project! But I'm not sure it's a good idea to put all of those fish together, and also, reading what you mentioned about keeping the Arapaima for a while and then giving it, I also don't think that's a good idea. If you get an arapaima, keep it for its life. You'll have to worry about the chance that the fish park might not have the space or want an arapaima that big (unless, of course, you've talked to them and they are willing to take such a large fish).