THE AQUIFERS OF CYPRUS  

 Cyprus has numerous aquifers and today, to a large extent, people depend on them for obtaining water for domestic supply and irrigation. The formation of these aquifers has resulted from a combination of geological factors and processes that took place during the geological evolution of the island from the Upper Cretaceous epoch (90 Ma) to the present.

Until the end of the 19^th century, groundwater was obtained from the aquifers of Cyprus through shallow wells, chains of wells, aqueducts and springs, and the quantities used were relatively small. Intensive exploitation through boreholes started at the beginning of the 20^th century and although it contributed to the development of agriculture and the economy of the island in general, it eventually led to the depletion of several aquifers and the intrusion of seawater into the coastal ones.

Cyprus has a semi-arid climate with an average yearly precipitation of only 500 mm, which appears to be declining in the last few decades. Severe droughts have also affected the island at frequent intervals. These naturally prevailing conditions were unfortunately not taken seriously into consideration in the management of the aquifers by the authorities. Many dams (photo A11) were constructed in the last 40 years in order to save water that would be lost to the sea and relieve the pressure on the aquifers. The situation has improved but the pressure on the aquifers is still there as the demand for water is continuously increasing.

The first scientific study of the aquifers of Cyprus goes back to the end of the 19^th century. However, comprehensive studies that led to the better knowledge and understanding of the subject, were carried out by the authorities through a number of research projects after the 1960s. The aquifer systems of Cyprus are today well known and most of the effort is directed towards their rational exploitation and sustainable management.

The aquifers of Cyprus have been subdivided into first-class and second-class (Figure A1) on the basis of their thickness and lateral extent conditions. First-class aquifers have been considered to be those that are sufficiently thick and of wide lateral extent and continuity over most of the aquifer area. They are found in Western Mesaoria, South-eastern Mesaoria and the Akrotiri Peninsula. The Troodos Aquifer also appears to satisfy the above criteria of extent and continuity and can be classified as a first-class aquifer.

The most important aquifer in Western Mesaoria is the Upper Aquifer (Figures A1, A2). It covers an area of about 400 km² and extends from the area of old Nicosia airport in the east to Morfou Bay in the west. It consists of gravels, sands and calcareous sandstones with intercalations of silt and clay of Pliocene to Pleistocene age. The aquifer is replenished from rainfall and from the flows of the rivers traversing the area of Western Mesaoria (photo A1). It has been pumped heavily (photo A2) in the last 50 years and there was seawater intrusion at Morfou Bay.

In South-eastern Mesaoria, the most important aquifer is the Sandy Aquifer (Figures A1, A2). It extends over an area of about 500 km². It consists of calcareous sands and sandstones, marly sands and gravels of Pliocene-Pleistocene age. The aquifer was exploited heavily in the 1950s-1970s. As the aquifer is replenished only from rainfall, it was soon depleted and seawater intruded into its coastal parts from Ormideia to Famagusta. In order to meet the needs of the people large quantities of water are now transferred to the area through the Southern Conveyor, a pipeline that takes water from the southwestern to the southeastern part of Cyprus.

In the Akrotiri Peninsula the most important aquifer is the Akrotiri Aquifer (Figures A1, A2). It covers an area of 42 km² and consists of gravels, sands and boulders of high permeability, with intercalations of silt and clay of Pliocene to recent age. The aquifer is replenished from rainfall and the flow of Kouris River, which has reduced considerably after the construction of a dam (photo A3). Exploitation of the aquifer started in the 1940s and heavy pumping resulted in seawater intrusion into the coastal parts.

The Troodos Aquifer developed in the igneous rocks that make up the massif (Figures A1, A2) and extends over an area of 3500 km². It is a fractured aquifer system and the groundwater is found in faults, cracks, joints and fractures that have developed in the rocks. Its water is generally of good quality.

Second-class aquifers consist of pervious layers of highly variable thickness and limited lateral extent. They are associated with the fractured and karstic limestones of the Pentadaktylos (Kyrenia) range (photos A4, A5), the reef limestone, gypsum and calcareous rocks surrounding the Troodos massif as well as the coastal plain and river deposits. Apart from the Pentadaktylos range such aquifers are found in the areas of Central Mesaoria, Kyrenia coastal plain, Karpas Peninsula, Kiti, Maroni-Anglisides, Pissouri-Paramali, Pafos, Chrysochou basin, Agia Irini-Kormakitis and Marathasa-Lefka-Xeros-Limnitis (Figure A2).

Many human activities during the last few decades resulted in the introduction of pollutants into the groundwater, which in turn led to the degradation of its quality. Such pollutants came from household and industrial waste (photo A9), fertilizers, insecticides and pesticides, farm waste (photo A10), mine waste (photos E1, E2) and seawater. The consequences of pollution on the health of people and the environment have nowadays been recognized and systematic and coordinated efforts are being made not only to prevent pollution but to reverse the adverse situation that is already prevailing with several aquifers.