Indeed: it is a rainwater cistern. An ecological installation carried out during the summer of 2023, as part of a sustainable water management approach at the Kangaroo Cottages in Dinant.
At the start of 2024, the installation is not yet fully operational.
This investment fits perfectly within eco-friendly home renovation approach . Responsible water management is indeed increasingly necessary in our time.
We will have the opportunity to present other initiatives undertaken with the same aim of contributing, at our level, to the preservation of our environment. And this achievement fully embodies our commitment to welcoming you to an eco-friendly guesthouse.
To tell the truth, we didn't really know what we were getting into when we started this project. Let us tell you…
Why install a rainwater tank?
But first, what is the purpose of this tank?
The first step is tosupply water to both toilet cisterns . This way, we no longer use drinking water in the toilets. Besides the environmental benefits of this efficient water management, it also represents a significant saving.
Secondly, the aim is tosupply the laundry room (sink and washing machine).
In this way, water from the distribution network is reserved for other domestic uses.
This cistern can also meet the water needs for the garden, such as watering plants in planters for example.
How did we design our ecological rainwater harvesting system?
The project was thought of from the start of the renovation of the house.
Indeed, it was necessary to install a separate rainwater supply circuit , distinct from the mains water supply. While separating the two circuits, it was still essential to be able to switch between them. The plumber installed both circuits, with a valve allowing the user to select the water supply method for the toilets.
The question of the type and size of the installation also arose.
Some advised us to install plastic tanks on the surface and put them in a battery. Beyond the inappropriate use of plastic, these tanks had a major drawback: the water heats up in summer and cools down in winter. The water in a buried tank is less sensitive to these temperature variations.
Finally, all experts agree thata concrete tank is more suitable, as it allows for the natural reduction of the acidity of rainwater.
Taking these considerations into account, a concrete tank is therefore preferred.
Very quickly, a problem arises: our garden is not accessible by a road, how can we bring a prefabricated concrete tank there?
A buried concrete tank, okay: but what capacity?
Before worrying about installing the tank, its capacity must be determined. Two parameters need to be considered :
- water needs
- roof harvesting capacity
Methods vary, but essentially we have estimated that a 4 M³ tank could meet our domestic uses.
As for the slope of the roof supplying the cistern, it can on average collect up to 30 m³ of water. So there is room.
Even though our needs could be met with a 4 M³ tank, we nevertheless opted for a capacity of nearly 10 M³.
As long as we're at it... You might as well plan and anticipate. Who knows tomorrow?
And so that the building is not too imposing in height, we will make sure to bury it almost two meters!
All right ! goes for a partially buried 10 m³ tank. But, incidentally, how is this achieved without a crane or truck?
A construction and work worthy of Hercules
A 10,000 liter tank is not insignificant.
What to do if it is not possible to transport a prefabricated tank?
Reduce it? Give up on the project?
A moment of recklessness must have occurred, and we opted for a self-build !
And from the beginning to the end of the project, nothing was easy. A blast!
First, while digging, we came across embankment earth, abundantly covered with bricks and stones of all kinds.
Tons of rubble to evacuate, not to mention the earth.
Having reached the bottom of the hole, we can finally pour a concrete slab and then begin to erect shuttering block walls, to a height of almost 3 meters. These blocks have the particularity of being hollow, to receive reinforcement (in order to reinforce the wall) and to pour concrete into them.
Concrete ?
If no truck can enter the garden, there is no question of bringing concrete using a mixer truck.
In total, almost 10 m³ of concrete were prepared using… a simple electric concrete mixer, to make the slab and form the concrete blocks.
Nearly 10 m³ of concrete, at a rate of approximately 130 liters per concrete mixer: do you do the math?
This work took us a week. Under the blazing sun some days.
Ecological products for waterproofing and a green roof
Once the tank was built and before making the concrete lid, we sealed the inner walls.
The products used are similar to those used in water towers. They are not incompatible with the purification of harvested water.
Tomorrow, nothing would prevent us from extending the use of this water to other domestic needs, such as showers, or even certain uses in the kitchen.
However, we did not initially take this option.
At the end of 2023, we installed a green roof on the concrete slab. In the spring, the flowers will brighten up this space. And you won't have to go far to find something to water them…
Except that…
By filling the tank with the water which falls quite well in the fall of 2023, we note with amazement that our tank... is emptying!
An investigation is needed to find and repair the leak. Then, in2024, we will need to install the pressure pump and connect the supply circuit.
One last detail: the overflow from the tank is not intended for the sewer: it flows into a soakaway, thus feeding the groundwater. A well of one cubic meter, filled with stones that we didn't have to go far to find.
An ecological commitment shared with our guests for sustainable tourism
As managers of Gites Kangourou Dinant, we are committed to contributing to a more environmentally friendly hotel industry and to participating in a sustainable tourism.
Our rainwater tank is just one example of a corporate green experience. And we don't regret the hard work to arrange it.
We invite our guests to immerse themselves in this eco-friendly approach. For those who are curious, we are always happy to share how our cistern works and the advantages of this installation.
It is an opportunity to learn and participate, even in a small way, in a relevant ecological initiative, which is part of sustainability.
Do you want to know more about sustainable water management for domestic use?
In order to carry out this installation, we were heavily inspired by the work of the late Mr. Jozsef Orszagh, well documented on the website www.eautarcie.org .
We can only encourage you to consult the valuable information contained on this reference website, dedicated to sustainable water management.
And to distract you… we offer you some photos of the work, carried out in the heart of the hot summer of 2023.
Do not hesitate to react in comments or to share this story on social networks. THANKS !
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