From where does the Mallorca water come?
There are many who live in Mallorca. About 900,000 live permanently on the island and about 8 million tourists come here each year (figures from 2015). As a rule of thumb each person consumes about 200 L per day for personal use. In total, this would give a water consumption of about 90 million cubic meters of water per year, mainly in the municipal networks. In addition, much water is used for irrigation during summer when cultivation of vegetables would otherwise have been impossible and for cultivation of oranges and lemons that are completely dependent on irrigation.
Everyone assumes that Mallorca has beautiful weather all year long, that is, little rain. This is not true. On average, Mallorca has about 500 mm of rain per year. As a comparison, Stockholm has about 500 mm, London 650 mm. The information about Mallorca is somewhat uncertain, different sources indicate from 300 mm to 750 mm, but most of them end up more or less close to 500 mm.
What gives the impression that it is raining less in Mallorca is the distribution of precipitation throughout the year: while in London the rainfall is evenly distributed over the year, and in Stockholm most of the rain falls during the holiday months (35% of the annual precipitation in quarter 3, July to September). The summer months of Mallorca are dry while most of the rain falls in the winter; in the third quarter in Mallorca 17% of the annual rain falls, in the fourth quarter 40%. The rain is also unevenly distributed over Majorca’s surface, much more rain falls in the mountains than in low-lying areas. Finally, uneven distribution also applies to the rain intensity: the rain in Mallorca comes as intense showers, grey days with drizzling rain hardly ever happen.
Mallorca has an area of 3640 km2. On this surface, 500 mm rain accounts for 1800 million m3 of water. Despite the enormous amount of water distributed through the municipal networks, 90 million m3corresponds to only 5% of the rainfall. Although much is also used for irrigation and industrial use, we collect less than 20% of the rainwater, the rest evaporates or flows into the sea, partly through streams and rivers and partly underground from the shores.
Tramontana is a rainy area. The plain is considerably drier. That and the temperature differences between the island’s parts determine what farming you have.
The flatland is suited for intensive cultivation of vegetables under plastic and for the cultivation of wine and almonds, which grows well in dry areas.
Soller is located on the slopes below Tramontana’s highest peak, Puig Major. Here on the north side of Tramontana, in the Soller Valley, oranges and lemons that require much water and a colder climate grow. The cold climate is needed for marketing: in a too hot climate, the oranges mature with green color, without the selling orange tone. The taste is just as good!
Water used to flow down the Tramontana slopes into the Soller valley in runlets. The farmers who had their possessions in connection with any of these could take water for irrigation of their property from the stream. When Soller grew, it was not practical to have many small streams of water flowing through the city and the water was led so that all streams ended up in the little river that now flows through the city. To compensate farmers who previously had free access to water, a system of water tubes and channels was constructed which led to the farmers who lost their water. They were then entitled to a given number of minutes of the river’s water per week. This right to the water is registered in the property’s deed and the municipality has officials assigned to allocate the water. On the farms, cisterns were built to store the water until used for irrigation.
There are large amounts of water pumped out through the municipal water pipes. It would not be practical to take it far away. The water is therefore collected as close as possible. This means surface water and groundwater from loose soil layers and water from the bedrock (call it mineral water). The mixture and therefore the quality and taste of the communities’ water are therefore very different in different places on the island.
Many residential areas in Mallorca are not connected to the municipal water. Often, private water pipelines have been built, where a central tank is filled as needed. Therefore, there are so many tanker trucks on Mallorca’s roads marked “drinking water”. They are also used to fill swimming pools as it is not permitted to fill them from the municipal networks.
The largest water consumption comes during the tourist season, in the third quarter. It is also the period with the least rain, that is why it is tourist season. During that time, the consumption is much higher than the inflow. It is therefore necessary to collect water when the supply is good to be used during the tourist season. It is then saved in large magazines. The large municipal water reservoirs form artificial lakes in Tramuntana, filled with both surface water and groundwater. The water levels in the water magazines is regularly reported in the island’s newspapers.
To increase the supply of water, in earlier years water was imported from the mainland. Tankers went up in French or Spanish rivers and pumped in water into the tank. The water was then pumped to the water reservoirs. This has stopped after facilities have been built for desalination of sea water. Desalinated water is mainly used for irrigation of golf courses and agriculture. Sea water is desalinated by a process called reverse osmosis (RO). To separate sea water and desalinated water membranes in which the water, but not the salts are soluble are used. With high pressure (about 60 bar) on the salt water side, you can have desalinated water flowing out on the freshwater side. With this technique it is possible to manufacture water that is sufficiently clean for chemical and medical purposes, rather than distillation. The membranes used to produce tap water and for irrigation are of lower quality, which gives a greater capacity but a lower degree of purification. In any event, the water is completely free from microorganisms and particles, and almost entirely from salt, the substances that are coming through are other substances from the sea water. The desalinated sea water I have tasted did not taste good – it was not salty but tasted rough and bitter.
In forthcoming blogs, I will review how the water is being cleaned and the differences between water from the tap and mineral water.