Will the islands’ water systems be able to withstand the successive waves of tourists and visitors that are added en masse to the more than half a million permanent residents of the Aegean? And this question can be answered positively as soon as possible this year, thanks to favorable weather conditions in winter and spring, but when it drags on drought dries up Western and Central Europe, nothing can cause complacency.

Especially when estimates for the near future show that water needs will increase. In 2030, the annual demand for drinking water is expected to grow by more than 32% compared to 2021 in the South Aegean region (Cyclades and Dodecanese) and by almost 16% in the North Aegean region. The National Drinking Water Operational Plan, developed by the Departments of Environment and Energy, Development and Investment, Health, the Interior, and the US Department of Defense, provides for an increase in the resident population in both regions until 2030 (from 347,512 people in 2021 to 386,647 human). in the South Aegean Seas and from 229,516 to 260,724 in the North), but also a significant increase in the daily population during the peak tourist season: an increase of 37% in the South Aegean Seas, in total 742,866 people, and 15% in the North Aegean Sea from 353,043 people.

Meeting growing future demands is clearly an intractable challenge, especially since climate models predict a 20 percent drop in rainfall across the archipelago in the coming decades.

“It is not enough to see total rainfall at the country level. It is necessary to see the spatial and temporal differentiation of water demand. For example, we have enough water in Western Greece, but much less in the Cyclades, especially in summer when their population increases significantly due to tourism. At the same time, there is practically no rain here from May to September. In addition, it is not only drinking water, but also agricultural water, which accounts for 70% of consumption,” says Mr. Simos Malamis, Associate Professor at the School of Civil Engineering of the National Technical University of Athens.

How is the situation today? “This year, despite the large increase in demand, due to the large tourist wave, there were no special problems with water supply in almost all Cyclades,” Giorgos Leontaritis, deputy regional governor of the Cyclades, tells K. . “Of course, there are problems with irrigation, watering the fields. The primary sector is struggling,” he adds.

The growing needs of the Cyclades are now covered mainly by desalination plants, which makes the transport of water by water tanks at the cost of expensive contracts with private companies. Aqueducts are only used in emergencies. 51% of the people of the Cyclades drink desalinated water, secondarily from underground water sources and a small part from surface sources (all figures are taken from the National Drinking Water Operational Plan). There are 39 large and small desalination plants operating in the Cyclades, and another 17 producing drinking water in the Dodecanese. Six desalination plants operate in the North Aegean region, as well as an oil refinery in Mytilini.

“The desalination water is of very good quality,” says the deputy governor of the Cyclades. “The problem is that these units are particularly energy-intensive and therefore costly, resulting in water being significantly more expensive than in the rest of Greece, and increasing costs for households and businesses. Water cannot cost a fortune,” Mr. Leontaritis emphasizes.

“Desalination plants are particularly energy intensive and therefore expensive, resulting in water being significantly more expensive than in the rest of Greece.”

Some surface water bodies are under high pressure due to increased demand, this is noted in the National Plan, for example, the artificial lakes of Marathia in Mykonos, Faneromeni in Naxos and Livadiou in Astypala, while the pressure in the lakes of Ano Mera in Mykonos and Apolakia in Rhodes is considered moderate.

An important problem is the over-pumping of underground accumulations in some places, although in general there is an assessment that groundwater systems are in good condition. Over-pumping often results in flooding and, in coastal areas, seawater intrusion into the aquifer. Pumping phenomena have been recorded at Syros, Katapol, Kamari-Fira-Emporio, Leros, Vathi and others. In the “backyard” of the tourist showcase, 50 settlements with a population of about 3500 people in Andros, Kimolos, Tinos and Mykonos are still without water supply!

Spot problems with drinking water supply are seen in Lesvos (Petra-Mythymna region), while in the northern Aegean, concerns about future sufficiency are observed in Chios and the small islands of Agios Eustratios, Psara, Oinouss, Fourni. Pumping phenomena have appeared in the underground systems of the Lesbos airport, in Mytilini, Plomari, Lemnos, South Chios, Mesokampos, Samos, etc.

Although the drinking water in the Aegean islands is generally of good quality, there have also been problems with exceeding the concentration limits for chromium, arsenic, nickel and nitrates, leading to the closing of certain wells, as happened in Rhodes.

The problem of water loss is very big, as in the South Aegean they are estimated at 30%! Estimates of losses between 10% and 60% are reported by the Municipal Water and Wastewater Enterprises (DEWA) in Kalymnos, Kos, Mykonos, Paros, Rhodes and Syros. Large losses are also reported in the northern Aegean, while significant sections of the networks need to be replaced due to age and construction materials (asbestos, iron).

The waterproofing of networks is one of the first measures imposed on them. “In the past, there were many violations that need to be addressed. Today, there are appropriate technologies for testing pipelines, such as waterproof cameras. But general planning is necessary. Small or large dams are needed on all the islands, as there are very few of them today. We need completed projects. Not like in Serifos, where there is a dam and an artificial lake, but there is no proper network for the use of water in general. It’s like we built a swimming pool on top of a mountain!” says Mr. Leontaritis. The deputy governor also emphasizes the need to conserve water, as well as channeling desalinated wastewater for irrigation after appropriate treatment.

Of course, the question arises of how overall planning will be carried out when, as noted in the National Drinking Water Plan, “most providers (DEYA or municipalities) do not have comprehensive general water supply plans or water safety plans, and in some cases they do not well-equipped technical services, no research. They face significant challenges in planning the necessary water supply projects over the course of a decade.”

According to Deputy Professor Mr. Simos Malami, the necessary water supply measures should be based on three pillars. “Firstly, reducing water losses in the water supply network and especially irrigation. Secondly, the use of unconventional watercourses. For example, desalination creates brine, that is, water with a high concentration of salts. Today we are throwing it into the sea, acting locally. With proper care, it can be used for irrigation. Wastewater can also be reused with safe methods at a reasonable cost to reuse water for agriculture or cisterns. In Greece we use only 2% and in Cyprus we use 70%. We can set a target of 10%. In addition, to use rainwater and precipitation. Especially on the islands there was a tradition with cisterns, which have now disappeared, although they were successfully implemented. Thirdly, save and not waste water in all areas. And in agriculture, where there should be drip irrigation, not surface. But also at home, where in addition to individual changes (for example, modern faucets), the “Savings” program for water, for more efficient washing machines or other systems, may also be required.”

Water from rain, water vapor, even from sewage

“Do as nature would” is the motto of a large research program for the conservation of water resources, which has been successfully implemented for two years on three Greek islands (Lesvos, Mykonos and Tinos) with six applications – pilot ones, as they are called. The Hydrousa project is more than just a water program as it experiments with integrated management and circular economy solutions that could pave the way for the wider application of its innovations. With 28 partners from universities, research centres, municipalities, NGOs and companies and a budget of 12 million euros, it has already been awarded twice at European level.

“Hydrousa is committed to developing, optimizing and demonstrating innovative and cost effective real scale systems for managing unconventional water flows such as wastewater, stormwater, groundwater, seawater and even atmospheric moisture. The goal is to extract valuable resources and reclaimed water, especially for relatively isolated island areas that are experiencing water shortages, ”says“ K ”program coordinator Simos Malamis from the NTUA Sanitary Technology Laboratory.

The first facility is located in the village of Antissa on the island of Lesvos with a population of about 500 people. The Hydro 1 pilot plant treats the municipal wastewater of the village, about 100 tons per day in the summer. Wastewater after anaerobic treatment (from which biomethane is obtained for energy purposes) passes through artificial wetlands, where it is filtered by gravel, reeds and other plants, followed by a decontamination process to kill pathogens. The sludge is composted, creating recycled water, which is used to irrigate various crops on an area of ​​10 ha (Hydro 2). “With drip irrigation and cheap sensors, we grow trees, tomatoes, corn, watermelons and even anise for local ouzo. Nutrients such as nitrogen, phosphorus, etc. have been preserved in the water,” says the program coordinator.

HPPs 3 and 4 in Mykonos consist of a rainwater collector that, by gravity, directs it into two 60 cubic meter tanks. Accordingly, rain and storm water is collected from 2-3 houses. “These waters are used to irrigate oregano, which doesn’t require much water, and then essential oils are produced,” Mr. Malamis says.

Hydro 5 in Tinos is an innovative system for treating brine produced by a desalination plant. In particular, the brine is collected in the panels, and under the action of solar radiation, the water evaporates and condenses so that it can later be restored. Hydro 6 maintains an exemplary eco-tourism installation in Tinos with systems for rainwater harvesting, water vapor condensation, wastewater treatment through wetlands and irrigation of local crops, which is an example of a different development of tourism infrastructure with respect for the environment.