A natural swimming pool offers a sustainable and environmentally-friendly alternative to conventional pools. As long as you have zoning permission, they can be a great addition to any home and are easy to integrate into any domestic environment. Reminiscent of freshwater rivers and lakes, they incorporate aquatic plants to create a closed ecosystem that keeps the pool water clean. As a result, they double as a stunning water garden, sure to become the highlight of any outdoor space.
Natural swimming pools can be designed to resemble a natural garden pond or something more extravagant. Whatever your tastes, a natural swimming pool will not only be a godsend on hot summer evenings – it will also add a romantic touch to your home.
This article will teach you how to build a natural swimming pool for yourself. It’s a lot easier than you might imagine!
What you’ll need to build your natural swimming pool
To build your natural swimming pool, you will need the following materials:
- Formwork boards and bars
- Liquid glass
- Clay & clay liner
- Tools: shovel // hammer // trowel // disc grinder // pliers // lead wire // spirit level
- Optional: cement mixer
Step 1: Calculate the dimensions of your pool
The main difference between a natural and traditional, chemically-preserved swimming pool is that the former has an extra area just for the vegetation, which serves as a water filter. The area for swimming and the area for plants should be approximately equal in size so that the plants can filter the water efficiently.
Professional landscapers recommend combining natural swimming pools with lush vegetation in the garden, as they complement each other very well. Moreover, as natural swimming pools don’t require coping or a paved edge, there is a smooth transition between the garden and the pool.
Step 2: Choose the best location for your natural swimming pool
When choosing a spot for your natural swimming pool, it’s important to consider not only the wishes of family members and their own aesthetic tastes, but also some of the main features specific to your site, such as the location of large plants, soil type, wind direction and the ground gradient.
Of course, swimming pools should not be built near large trees, especially poplar, willow or chestnut trees. During dry periods, their roots will grow towards the water and can damage the pool’s waterproofing. Furthermore, removing the leaves every day can be a tedious job. If they are left in the water, they will decompose and contribute to the rapid development of green algae.
Step 3: Choose the shape
It can be very tempting to recreate a stunning photo of your dream pool, but building your natural swimming pool, ending up with something out of the ordinary could make life more complicated for you.
A swimming pool with a complex shape is much harder to clean and maintain. You must calculate the optimal position for the filters and their power supply very precisely and continue buying additional reagents. The number of problems you encounter will depend on which shape you choose. According to industry experts, the best shapes for a swimming pool are rectangular, square and oval. If you want something more elaborate, we recommend focusing on a feature such as the pool steps.
Step 4: Configure your pool
An artificial pond, or eco-pool, is made up of several distinct areas or zones. They work together to keep the water clean in a natural, chemical-free way:
- Filtration zone (decanting);
- Regeneration zone (biotope purification zone or microorganism cleaning zone);
- Oxygenation zone (this can be a current, waterfall or a single stream of water);
- Swimming area
The principles of running and cleaning a natural pool are both simple and complex. The reservoir is made up of two zones: deep and shallow. The difference in depth generally varies from 30 cm to 2 m. The deep zone is designed for swimming, while the shallow zone purifies the water and becomes a decorative feature.
The latter generally contains a large number of plants. This area is a water garden, which is also known as the “regeneration zone” or “plateau”. Plants both feed on organic matter that falls into the pool and help purify the water. The range of vegetation is selected specifically to control the overgrowth of harmful algae. The plateau can still be inhabited by a natural colony of microorganisms that contribute to keeping the reservoir clean. While the water gets cleaned by the interaction of aquatic plant systems, together with phytoplankton and zooplankton, water circulation occurs because of the simplified filtration system.
Step 5: Excavate and fortify
- When you are ready to start building, mark out the pool area.
- Remove the soil and set it aside;
- Dig a hole: start digging the rough outline of the hole first and then line up the walls;
- Cover the edges of the hole with planks to create a walkway; this will stop the soil around the edges from becoming compacted;
- At the bottom of the hole, lay down a clay liner and plot accurately;
- Use a measuring wheel to check the dimensions of the hole
- Finally, use the grinder to cut the valve stems to the desired size
- Approximately 5 cm from the top of the ditch, drive in the rebar around at 30-cm intervals; Once you’ve finished installing the valve, add its horizontal tubing. The distance between the horizontally positioned rebar can also be 30 cm, although you can reduce it if necessary. Attach the fittings with wire and tighten them with pliers;
- Arrange the plumbing system using the design for water purification and collection.
Step 6: Prepare the floor of your natural swimming pool
- Prepare the mortar, mix the cement and sand, then add the gravel and water, and stir the mixture in the cement mixer. If you don’t have a mixer, prepare the mixture manually. The proportions required for the making concrete mortar are as follows: 1 part cement, 3 part sand and 4 parts gravel;
- Once it is ready, pour the concrete mixture onto the bottom of the hole, smooth it out, close and let it dry for at least 12 to 14 hours.
- Note: During the concrete work, don’t forget to build a small slope so that the water will move towards a specific area. This extra step will make it possible to drain water through the pump.
Step 7: Setting up the formwork panels
While the concrete shell at the bottom is drying, you can start making panels for the formwork:
- Cut the boards. Keep in mind that once the boards have been installed, there must be at least 13 cm of space between the walls and formwork.
- Hammer all the board panels and cut boards together.
Step 8: Install the walls of your natural swimming pool
Before installing the formwork, place the roofing material on the bottom of the concrete shell and cover it with panels so as not to limit the installation of the formwork.
- Place the formwork panels inside and join them to each other;
- Prepare a mortar solution in the same proportions as you mixed for the concrete at the bottom of the hole;
- Lay the concrete in layers of 15 to 20 cm and compress each layer.
Finishing your walls
Remove the formwork, smooth the pool walls and finish the surface and bottom of the pool with a layer of liquid glass. Alternatively, you can choose to finish the walls with tiles.
Step 9: Your water filtration system
The principle of lake filtration
In an artificial pond or a natural pond based on a biological filter, you must recreate the natural process that helps maintain a balanced aquatic environment. For this, you will be applying the principles of water treatment in natural lakes. An eco-pool works because of the constant exchange between upper and lower water layers, which is caused by temperature differences in larger pools and forced filtration in small ones. Through this process, water passes evenly through the biofilter, eliminating any impurities and enriching the water with nutrients.
Mechanical filtration system
In lakes, water is cleaned and filtered through a biological filter. However, to ensure that the water is kept in the best possible condition, dry leaves, residual grass and other contaminants must be removed quickly from the surface of the water. To achieve this, you must use a mechanical filtration system to help ensure the biofilter is not overwhelmed by this unnecessary extra load. In the cleaning process, mechanical filtration accounts for 20% of the total filtration. Its main task is to extract large, suspended particles from the water.
This accounts for 80% of the total filtration. The shallow area, which is the regeneration zone, is inhabited by microorganisms and aquatic plants that serve to filter the water. As a result, the water is cleaned and the necessary natural balance is maintained; this is what distinguishes natural swimming pools from pools treated with chlorine. The most important is to extract nitrogen and heavy metal nitrogen compounds, NH4, NH3, PO4, NO3, NO2 and Fe2O. Specially selected plants and microorganisms will maintain the regular hydrochemical system.
Step 10: Maintain, maintain, maintain
Natural pools are generally much more cost-effective to maintain than their traditional counterparts. Instead of needing constant monitoring to check the condition of the filter, they simply require annual treatments to keep the plants healthy:
Keep an eye on the water level, which might need topping up, but you won’t need to change the water itself. Ensure the pool bottom is cleaned and your plants are pruned once a year, so they don’t overgrow. Once finished, your eco-pool will require maintenance. To keep it in good condition, you must regularly remove leaves, dead parts of the plants and clean the filter networks. In addition, every five years you will need to deep clean the reservoir to remove silt and debris.
Finally, an eco-pool does not require winter maintenance. For regions that see temperatures plummet in winter, the pool can even be turned into an ice rink!
All that’s left for you to do is take a dip in your natural and safe swimming pool. And don’t forget to give yourself a pat on the back! You’ve taken the first step towards creating a garden that is in harmony with the natural environment.
Did you enjoy this article on how to build your very own natural swimming pool? Why not read more about how to easily heat your pool or even our guide to selecting the right pump filtration system for you!