Sa
Marina is located in the south of Ibiza in an area where the
groundwater has fallen significantly due to overexploitation. As a
result, seawater flows in and the groundwater becomes salty. The aim of
the "Sa Marina" pilot project is to prove that villas in rural areas,
which have previously consumed enormous amounts of water, can be
operated through intelligent and sustainable water management without
further exploitation of the groundwater. This is done through the
consistent use of rainwater and the reprocessing and use of waste water.
Nature-based
solutions are used, as required by the EU Green Deal. In the medium
term, the pilot project should lead to a change in the law that promotes
and demands local, sustainable solutions as “good practices” instead of
hindering them.
It
is not only the rainwater from the roofs that is collected and stored
in a separate cistern, as required by law. The rainwater that falls on
the rocky hillside is first channeled through small canals ( key lines )
to seep away to the permaculture terraces. This massively reduces
surface water runoff and erosion and remediates the groundwater. When it
rains in Ibiza, it often takes the form of heavy showers. A typical
time is the third week of August. Then so much rain falls in a short
period of time that it cannot seep away even in this optimized system
and runs off on the surface. In Sa Marina, this excess is channeled into
an artificially created biotope with native freshwater vegetation,
which also offers a large number of animal species the habitat they lost
on Ibiza. When the biotope is full, the water flows into underground
storage tanks, where it is protected from the sun and evaporation and is
available for irrigation or use in the home.
Since
these underground tanks and the biotope have so far been interpreted by
the authorities as buildings requiring approval and (wrongly) as
sealing of the landscape, they cannot be implemented legally, or only
with great effort and approval procedures lasting years. Since the world
needs good solutions quickly, we decided to build these minimally
invasive tanks “illegally” in order to be able to prove how the concept
works.
We
were promptly caught by the environmental police and the head of the
authorities immediately demanded a site inspection. After extensive
discussion and explanation, she also recognized the dilemma that
excellent, forward-looking water management is prevented by
old-fashioned laws. In order to avoid sanctions and to encourage this
fantastic project, she declared it a pilot project, with the proviso
that I keep her informed of the results and improvements made. This also
includes the development of biodiversity, carbon fixation, improvement
of soil structure, water retention capacity, microorganisms... more on
this in a later newsletter.
On
April 8th this year, the University of the Balearic Islands, UIB, and
the Water Alliance organized a “Technical Information Day on the
Recovery of Aquatic Ecosystems” where I will present the Sa Marina pilot
project. After that, the technicians and heads of authorities for
environmental protection from various town halls came to visit the
project on site.
In
order to promote these solutions and a rapid adjustment of the law, a
study was commissioned from the Water Alliance ( Alianza por el Agua de
Ibiza y Formentera ) to show
* the historical use of water on Ibiza with comparable techniques
*
that these are not "sealed areas" within the meaning of the law, since
erosion is prevented and seepage is promoted and thus serve to remediate
the groundwater
*
the use in the house and garden replaces a groundwater extraction and
this water concept should flow into the law as "good practice" in the
medium term.
All
of the waste water is biologically cleaned in a house sewage treatment
plant and a downstream constructed wetland or reed bed filter so that it
can be used in the garden or for flushing toilets. Drinking water is
produced by condensing the humidity from the air with the help of solar
energy, so water bottles are becoming obsolete.
Since
enough rainwater falls on Ibiza, but most of it drains into the sea, we
will build more rainwater tanks on the entire property in the long term
and filter the water biologically to cover the entire water needs of
the villa.
In
the meantime, Daniele Pedretti from the University of Milan has become
interested in the project and has installed sensors in the rainwater
depot with which the water level can be checked via the Internet. In
this way, data is obtained that shows which precipitation is necessary
to fill the depot. |