Planing before the construction:
Chose the desired fish species. Document on their needs. Calculate the desired on the size of the pond. Order the equipment and read the instructions manual. We will need this information later on when we plan the internal layout.
A minium size would be 2m width * 2.5m length * 1.5m depth. If the pond is too big it is very difficult to catch the fishes if they need medication. It is also quite difficult to see the fishes if they chose to hide, this might be a good or a bad thing depending on your own taste. Unless you opt in for a natural pond, all the water has to be cycled every 3-4 hours. This will translate in a very big filtration system.
For very big ponds consult the local legislation. There could be legal problems with the large bodies of water in some countries.
Consider having some kind of shade nearby during part of the day. The algae grow really easily on sunlight and will compete with the rest of the plants for nutrients or require additional water treatment and maintenance.
If the sun warms the water all the time there is a high amount of evaporation and a higher then expected temperature. Consider the preferred water temperature of the fish species that will live there.
If the tree above the pond has needles they can get to the pump. Make sure that the mechanical filtration is adequate or there are intermediary reservoirs where they can sink.
Before starting to dig consider where the excavated earth will go. Building a framing it is one of the best options.
Mark on the ground, with wire, wood, rope etc the shape of the pond. Reposition the marking until you are fully satisfied with the location. If possible leave the marking for about 24 hours just in case you get a better idea. Moving a very big whole is not an easy task especially after the pond has been filled in.
Place the equipment on the ground and make sure the desires shape can accommodate it. Also place the hoses and pluming. Don’t add un-necessary labor for cleaning.
Plan the depth and the shape of the pond. Do take into consideration the height of the insulation, underground hardscape and pluming. Remember the intake should be on the opposite side of the outlet in order to create a natural water flow.
The plants should be planted at about 1m in depth because the fishes like to swim around their roots and if they are not deep enough they will get eaten by the wildlife. Also consider the plant roots system. There are some that required about 30cm or more. The plants will help with the filtration but they do not allow a powerful water movement. Most plants like still water.
The downside would be that the fish’s waste will not reach the filters fast enough and sediment on the bottom of the pond. In case of water treatment, with medication, the plants may melt. The plants should be moved before the pond is medicated. Be very careful when adding new plants. They should be quarantined before.
The sick fish will hide among the plants.
If you want plants just for the looks of it do look into ferns. They like humidity, provide shade and look beautiful.
Liner vs. concrete:
The liner it is more labor intensive but cheaper. It is preferred by DIY community because of the cost. The concrete is more general and easier to be dealt with. The pluming for the liner will be covered by the whole body of water and it might flatten the pipes at some point. With concrete this is not a problem.
The concrete it is more smooth and easier to clean. The liner can get punched. The concrete can’t.
It is generally easier to spot and fix a concrete pond with some water resistant solution. However, the liner has a rubber-ish texture and it needs to be patched and glued.
Shape of the pond:
Try not to build edges or places that crate still bodies of water. In those places the filtration will be very inefficient.
The bottom of the pond should not be flat. If it is flat it has to be cleaned all the time because the debris will collect in a layer. There should be draining sections on the bottom of it so that waste will reach the skimmer as soon as the fishes scramble the substrate.
A new bottom drain should be added for every 2 square meters of pond. The minimum depth next to the walls should be around 1.2 meters in order to maintain a constant temperature. Another upside of this depth is the amount of gallons of water. A larger water body helps with a way more stable ecosystem. The small changes in water chemistry are close to non existent.
If the liner will be all the way to the bottom of the pond use wooden beans on the upper lip of the walls in order to allow the viewers to walk on them around the pond. Else have in mind that the wet earth will not sustain a human’s height and build some pylons.
In case of opting for a concrete based insolation before building the internal frame place the stones that will sustain the concrete.
For the waterfall consider the speed of the water according to the fishes’ size and species. They should not be washed away by the current or struggle to keep up with it. A wider waterfall will have a slower speed. A narrower one will have a faster speed. The height of the waterfall matters as well. A 3% slope is required in order to create a water flow.
Consider the amount of concrete required to build the walls and floor. We might talk about some tons of concrete.
Make sure you dig in the space required by the equipment: filtration, lightning, reverse osmosis etc.
Planing during the construction:
Before proceeding with the liner in any way set up the pluming.
If multiple liners are used make sure they are overlapped for a good section – about 1 meter.
1) Make the pond abrupt at the edges. It prevents the predators from fetching the fishes.
2) The pond should be as deep and large as possible/desired because it is very difficult to expand it afterwards. Nearly the whole setup has to be re-built.
3) Use big boulders on fast flowing streams. The small pebbles do get washed away by water.
4) Do not use too many boulders, create some terraces on which flowers can grow. It creates a more natural look.
5) Use dirt and gravel to simulate the natural look as much as possible.
6) Do not plant too many water plants one next to each other. All the plants tend to expand and grow.
7) There should be crevices and tunnels in which the fish can hide from predators.
8) Have proper water movement and aeration. Else the algae will keep on growing and take over the pond. Have the intake and outlet in opposite directions in order to create a water flow. Avoid the 90 degrees turns. It does not look or function ok. The water wants to go forward not to the left or right. Have multiple smaller waterfalls along the way if necessary.
9) Allow proper and easy access to the mechanical and electrical systems. This ensures maintainability on the long run.
10) Make sure there is a grill with the wholes small enough in front of each intake. It should prevent the fishes from getting into the systems and die. The flow water should allow the fry to swim against and not get sucked into the pumps.
11) Have ledges on which you can stand next to the water and enjoy the fishes.
12) If you opt in for a more self-sustaing pond do not have the liner on the very edge of the pool, allow some dirt on the sides for the plants and worms. This area for regeneration and filtration should be almost equal in surface with the deeper area. The more fish we are having the more insects they require and the more waste they produce. Consider a fish’s belly. Its digestive system is not optimal. It needs to fill its belly a few times a day. On top of this, the fish’s food needs to eat healthy and regenerate back as well. Having this in mind let’s hope we understand why we need so much space and water for a healthy environment.
Make sure that the liner is covered with rocks, dirt or gravel. The UV rays from the sun will age it and it will leak.
If you use underwater lightning now it is a very good moment to hide it among the rocks.
After the rocks are added, use waterfall foam to cover the undesired cracks from the waterfall stream. The water should flow on top of the rocks not underneath. The scope is to have a beautiful landscape.
Render the pond with waterproofing material if needed.
In case the pool has also an above the ground wall add the desired decoration.
Before adding water to the pond, for clarity, do wash the rocks and gravel. Use a suction pump to remove the dirty water.
Place bolders around the fertilised ground used for the overground plants. This will lower the erosion. Of course, only if it is desired to have a different dirt then the rest of the yard. Else leave the dirt as it is and plan at will.
Fill the pond and start the waterfall. Adjust the flow with rocks until the desired aspect it is achieved.
Cut the extra liner but leave a decent width on the side. Cover the edge with gravel. This should create a transition between big rocks and the dirt.
The landscaping of the waterfall mould and the addition of optional fertilisers should be done now.
Add the optional beneficial bacteria or a small amount of small fish and cycle the pond for a while. In this period the pond’s perimeter can be cleaned of dust, dirt, rocks, debris.
1) Make sure the systems are clean else the flow lowers and other problems are triggered.
2) The extra food will get stuck into the filters.
3) Have loads of natural filtration from plants. Waste decomposition is a very good thing. The insects and frogs will pop up and they are a great source of food for the pond. The plants should be both floating, submerged and emerged. The fish do eat some of the leaves naturally. Various sizes of Duckweed, water hyacinth, pickerel weeds and Anacharis. Do note that all those plants are invasive. They should be planted and have some delimiters on the body of water limit their territory. A separate part of the pond can be used as a filter with all those plants leaving the rest of the water body for viewing the fishes. Alongside with the fast growers we just discussed about, have some slower growing plants.
4) Have various species of fish, They have their own role. The ones with their moth upwards (like guppies) eat mosquito larvae. The ones with theirs straight eat insects and everything that swims in the water. The ones with theirs downwards will help up clean the algae.
5) If possible and desired try to set up a few grow-beds nearby for vegetables and flowers. They do grow really fast with nitrates enriched water and help a lot with the filtration. This can be done along the pond’s river, the water will flow naturally.
6) Have some of the roof’s drenches (if not all) to collect the rain water in a big pipe and direct it towards the pond. Also, if possible, have some kind of storage facility for the more dry reason.
7) Have solar power for the water pumps.
1) Create a natural food chain as much as possible. This should include some fast breeders as well which are the food source of the other creatures.