The phenomenon Their beaches have been experiencing problems with salt water for years Halkidiki.
What is the phenomenon of boiling or boiling?
As mentioned in the RES, salinization is a phenomenon related to the over-pumping of water in coastal areas to meet the needs of agriculture, but to a lesser extent tourism and residential development. The problem is multifactorial.
Thousands of wells, both legal and illegal, actually operate at “full capacity” during the summer months. At the same time, it is a common secret that the land of Halkidiki has been “ploughed” for decades by illegal networks, created by private individuals, and illegally transported water from these wells for kilometers – while the law allows it to be transported. up to a maximum distance of 800 meters.
THE climate crisis In many areas, the irrational use of water, which lowers the level of the underground water bed even by 10 meters, to the height of a four-story residential building, also causes the phenomenon of swamps.
How is lowering of groundwater levels related to salinity?
APE-MPE reported on this«Put very simply, fresh water acts as a kind of “barrier” to marine life. Thus, when its level drops too low, seawater intrudes because the dam “falls” because the natural hydraulic gradient toward the sea is reversed. The problem is not new, but it has been getting worse in recent years.”
“We have been dealing with the swamp problem for years. The very rapid development of intensive olive cultivation in our region, especially after the end of the 1990s, the lack of rain and prolonged heat waves that increase the need for irrigation exacerbate the problem,” said APE-MPE to the mayor. Polygyros, George Emmanuel.
And he explains: “The city of Poligyr was supplied with water from the plain of Kalyves, which is located near the river Olynthios. However, in the last 20 years, olive cultivation has grown more and more and thousands of new trees are planted each year, resulting in correspondingly increased irrigation needs. At the same time, water for irrigation of agricultural fields is irregularly transported from wells to very long distances, even kilometers. A fixed well with an output of 10 cubic meters can irrigate 100 hectares, one of 100 cubic meters, 1000. So when there is excess water, it is moved to another place. Legally, it can be transported up to 800 meters, but it is an open secret, for decades, water often travels for kilometers, transported by illegal networks, built by private individuals.
If illegal drilling is a clearly condemned phenomenon (the exact number remains unknown), the continuation of olive cultivation in Halkidiki is absolutely necessary.
“We cannot put farmers in front of the street and shoot them. Instead, serious investments are needed in smart agriculture that can limit unnecessary water wastage, but also in more rational water use, such as drip irrigation instead of nozzles where much of the water evaporates. , but and irrigation is not horizontal and appropriate to the specific needs of each crop,” says the mayor of Polygyros, noting that the agricultural sector in his area of responsibility currently absorbs 90% of water. Together for tourism and residents, 10% (of course, tourism and citizens demand high-quality and potable water, unlike the primary sector)” he emphasized.
According to Mr. Emmanuel, “we need to look at the issue comprehensively, for example, instead of over-pumping from wells, “the water from biological treatment can be used for irrigation, reservoir after treatment”. this, of course, requires the implementation of the necessary biological treatment projects, many of which are still lacking, but also the creation of sewage networks to be connected to biological ones (which in many areas do not exist). On the coastal front of Poligiros, there is a need to modernize the water supply networks, which in some cases are more than 50 years old, as a result of which at least 40% of the water is lost due to old age and moreover leaks. Water theft is easy. For all this to continue, of course, considerable funding is required, which is not always easy to obtain for various reasons.
Any “peaceful rain” and water flows that Greece does not control
According to Konstantinos Katsifarakis, professor emeritus of the Department of Civil Engineering at the Aristotle University of Thessaloniki (AUTH), Greece’s common salt water problem is widespread due to its long coastline. On almost all islands, even Crete, the problem is mainly groundwater, but saline intrusion also exists in estuaries. With the exception of areas such as Halkidiki, and the Pieria region where crops and tourism are often adjacent to the sea, the salt water problem is not particularly agricultural.
“This is mainly related to tourism – due to the temporal and spatial concentration of water consumption in specific areas during the four months of the year – but also to the development of settlements in these areas. In some cases, such as in Northeast Halkidiki, mining activities also play a role, which requires a lot of water,” explains the professor.
How is the wetland related to the lowering of the groundwater table?
“They are completely interconnected because there is no ‘dam’ from freshwater for seawater to penetrate inland. So if the water level drops, the sea ‘comes in’. And climate change is certainly having an effect. We have long periods of drought, as well as heavy rains that caused floods – as much water fell in Volos in two days as last year, but what to do with this water? the table needs to be enriched
“peaceful rain”, gentle rain” notes.
“Today, in some areas in the north of Greece, the water level has dropped by more than 10 meters, and in the areas of Thessaly, this is not unusual in recent years,” the professor notes.
In response to the question of how much annual water deficit is calculated in Northern Greece, Mr. Katsifarakis explains that since the problem is of a local nature (in specific areas with a lot of tourist arrivals), we cannot talk about a deficit during the year. time (months of high demand tourist season). In addition to the spatial and temporal concentration, the problem is also related to the fact that Greece does not fully “control” many water “pipes”.
With the exception of the Aoos, which originates in Greece and continues its waterway in Albania, all other transboundary rivers through Northern Greece originate from other countries. As a result, Greece depends on the management of river waters by neighboring states.
For Thessaloniki in particular, Mr. Katsifarakis points out that although the sea has long penetrated the basements of buildings located close to the sea (for example, on Nikis Avenue), it does not make sense to speak of a swamp in the urban fabric. Thessaloniki is supplied with water from Aliakmonas and Arabissos, and boreholes are available only in a few stadiums in the city.
Natural detoxification takes months or even years
Saliva is considered pollution because when salt seeps into fresh water, it cannot be used by humans for further use. How easy is it to clean? “Natural decontamination is a time-consuming process, as it takes months or even years for freshwater levels to rise. During desalination, the issue is not time, but energy consumption. Even for reverse osmosis, it takes a lot of energy to get clean water,” notes Mr. Katsifarakis.
In his view, preventive measures such as enriching the water table by impounding groundwater through small dams “as the great Manolis Glezos did at Aperatos, Naxos” are more appropriate. Also, in coastal areas where new tourism farms are developed, simple but important measures can be taken, such as installing a double water circuit to pump brackish or brackish water for use in toilets, in particular. it is successfully implemented in several other countries. “Legislation should also be improved to better define the duties of bodies and organizations, because today there are many people who are responsible for the same issue, which does not work effectively,” concludes the professor.