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water management


Water...After love, the most precious thing on earth.

The amount of water on earth does not vary but must be distributed among more and more people. Reason to use it sparingly. At La Tierra finca we have taken some measures, which we will explain further below:
Scroll down to learn about our swales, reed bed filter, compost toilet and swimming pond.



The South of Spain, Andalucia is dry, or is it? The average annual rainfall is 559 mm and in Mijas where Finca La Tierra is 607 mm. For comparison: in London it is 621 mm per year. So not a big difference, only the distribution over the number of days is very different, in Spain it rains less but more intense. In addition, the soil is harder and can absorb less water. That is a shame because the soil is the best and cheapest way to store water. And that is exactly what we want to achieve with the construction of swales.



We have two driveways to our land and the lowest turns into a river when it rains. If we do nothing, the water will run off the land again and that is a shame because we need it so badly. So what we do is slow the water, spread it and soake the land with it, the theory behind swales.

It will take a while for the soil to become saturated, but long term it will yield a huge advantage.

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reed bed filter


Unfortunately, in our house we can´t separate black and grey water. The whole water recycle system (reed bed filter) could be a lot smaller if we could..

Our tubing for waste water is for black and grey water combined, so we don´t have a choice.Or do we?

Yes, a compost toilet is the answer.

It would mean, no more black waste water and a valuable gain for the compost heap. We do have a "dry toilet" in the garden, see below.

So, for the time being, as far as the house is concerned, we have mixed waste water that needs to be cleaned.


At Finca La Tierra we have our own well, that, up till now, has given us sufficient water. 

Nevertheless, we live in an area where every drop counts, so we decided to clean the water as much as we can and use it at least twice. Have a look at how we made a Reed Bed Filter 

the ochre room

All our waste water first goes into a classical 3 chamber septic tank.


Solids and grease stay behind and out comes dirty water, that runs into a deposit with a pump.

From there it goes in small portions and short time intervals on to the filter bed.

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Aanleg helofytenfilter maart-april 2009

We built a 9 m3 bassin, laid all the tubing and filled it with rock wool as substrate for the plants.

We got the rock wool from a green house in El Ejido, Spain´s largest agriculture area close to Almería.. It meant two long journies with a van to one of the most depressing landscapes you have ever seen: plastic, plastic and more plastic, as far as you can see.

the sienna room
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The Sienna Room

The Sienna Room

The rock wool was covered with marmolina, marble gravell, to avoid any smell.

​And than it is time to put the pump on. The dirty water goes into the filter and out comes cristal clear odourless water, ready for a second life...

The bacteria around the roots of the plants live of the nutrients in the water. The reed plants are the perfect suppliers of oxigen down in the filter and we added a tube to provide even more oxigen as the bacteria that do the clean up are aerobic, which means they can only live and do the job if there is sufficient O2.


Garden and Pond

Garden in Winter

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And then of course the big question is, how clean is the water when it comes out of the filter?

The answer is given by the analysis. The attached photo shows the values ​​of the water before and after passing through the filter. The most important parameter is the amount of oxygen required to biologically and chemically clean the water, which has gone down spectacularly. 

The conductivity is another indicator, which has decreased less, probably due to the large amount of nitrate and phosphate in the original waste water. But the water eventually goes to the garden and the plants are only happy with it.

The results of this analysis were so good that people from the laboratory came to see the filter because they could not believe that plants can purify water so well.

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compost toilet

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There are still many people in the world who cannot believe that we wash away our physical waste with purified drinking water. And you can't blame them. Sewers are reprehensible. In addition, they also drain rainwater, really incredible.

The solution is so simple (and so hygienic), a compost toilet or dry toilet.

The one we have separates urine and faeces. The urine goes directly underneath a layer of mulch into the garden and number 2 falls into a (biodegradable) bag and is covered with sawdust or another carbon additive. As a result, the aerobic decomposition can start immediately and a possible bad odor is avoided.

When the bag is full, it goes on a separate compost heap and stays there for about a year and a half to ensure good composting and to ensure that all pathogenic micro-organisms have disappeared.

And believe me, it is completely odorless.

In this way we save many liters of water and we keep all the nutrients that we would otherwise flush away on our site.
The Chinese economy was based on this cycle for 4,000 years, until about 50 years ago Western civilization had to make its appearance ...

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swimming pond

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The swimming pond is a project from about 10 years ago.

The pond consists of 3 parts: a deep (3 m.) part for swimming, a part of about 1 meter deep for lilies to cool the water and finally the shallow part where the helophytes are, the plants that purify the water. This is only 30 cm deep.

The plants are on a felt-like cloth and underneath are the tubes that suck the water from the pond to get back into the deep part. The circulation is important, in the summer the entire volume of the pond (approx. 60 m3) must pass through the regenerative zone at least once a day.

The result is a clear pond with living water, all kinds of insects live in and around it. A huge asset to the garden's biodiversity.

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