|The rainfall is unevenly distributed geographically with the highest in the two mountain ranges and the lowest in the eastern lowlands and coastal areas. Additionally there is great variation of rainfall with frequent droughts spanning two to four years.|
The average annual net rainfall of 275 mcm is distributed between surface and groundwater storage with a ratio 1:3 respectively. From the underground storage approximately 1/3 flows into the sea.
|WATER BODIES (in general)|
Most rivers originate in the Troodos area. The seasonal distribution of surface runoff follows the seasonal distribution of precipitation, with minimum values during the summer months and maximum values during the winter months. As a result of the Eastern Mediterranean climate with long hot summers and a low mean annual precipitation, there are no rivers with perennial flow along their entire length. Most rivers flow 3 to 4 months a year and are dry during the rest of the year. Only parts of some rivers upstream in the Troodos areas have a continuous flow (rivers of Xeros, Diarizos, Kargotis, Marathasa, Kouris and Germasogeia). Most rivers have a rather steep slope except for the rivers in the lowland areas along the southern coast. Most part of the rivers is, however, at mid-altitude.
As a result of the dry Mediterranean climate, there are only 5 natural lakes which are brackish or salt. The other water bodies are created by human as a result of damming of a river or the creation of storage basins. All the lakes in Cyprus can be characterized as dynamic systems. The natural salt and brackish lakes dry up regularly, but not every year. Both the salt and brackish lakes contain typical species for these conditions. The amount of water in the reservoirs and storage basins is depending on the rainfall and use. The reservoirs are also mainly filled by the inflow of water from rivers. During winter they fill up but in summer most of the water is used and the water level declines. Consequently, the water level and size of these lakes is variable. As all reservoirs and storage basins are structured with the objective to provide water for drinking or irrigation, all these lakes have the possibility to dry out, which they often do in reality.
Most of the Island aquifers are phreatic, developed in river or coastal alluvial deposits. These are the biggest and the most dynamic aquifers, replenished mainly by river flows and rainfall. There are three large coastal aquifers that include all the perpendicular riverbeds. The coastal parts of these aquifers are composed by sands, silts, limestones, conglomerates and clays. Riverbeds consist of alluvial deposits, gravels, sands and silts. These aquifers are phreatic and are around 30 m deep. Apart from the large but not so productive aquifer of the Troodos igneous rocks, other aquifers exist in gypsum, sandstones, limestones and chalks. These aquifers are mainly phreatic with some parts being semi-confined to confined. These parts are covered by silty-clayey layers or marls, sandy marls. It is noted that the aquifer of Troodos Mountain has been developed generally in low permeability ophiolites and locally in medium permeability fractured zones of igneous rocks and it is therefore confined in places.
All the aquifers of Cyprus (66) have been grouped into 20 groundwater bodies, mainly based on lithology, the hydraulic characteristics, the pressures and the importance of each aquifer.
Ten groundwater bodies have a connection with the sea. The Lemesos groundwater body has outflow to the sea have a discharge up to 350 m3/h, while the others have discharge recharge below 150 m3/h. Most groundwater bodies are phreatic with parts that semi-confined or confined. Only the Maroni gypsum is completely confined.
The ecosystem of the Fasouri marshes (near Akrotiri salt lake) is the only ecosystem in Cyprus directly depending on groundwater and more in particular on the Akrotiri groundwater body.