Thiva

The study area is located in the northern part of Thiva valley which belongs to both Viotikos Kifissos and Assopos River basins. The study area covers a small part of the porous groundwater body of Thiva-Assopos-Schimatari. Water network is not well developed due to low relief while the main two streams (Kanavaris and Kalamitis) discharge to lake Iliki in the northern part of the basin.

Regarding the geological background, serpentinized ultramafic rocks mainly crop out in the vicinity of Υpato and Mouriki villages and Limestone of Cenomanian–Turonian age outcrop north of Iliki lake. Quaternary is characterized by the presence of alluvial deposits that floor most part of Thiva valley whereas Pliocene–Pleistocene sediments consisting of marl, clays, sandstone and conglomerates cover the eastern part of the valley.

The main aquifers in the area are the karstic aquifer developing in Triassic-Jurassic limestone and the porous aquifer within Quaternary deposits and Neogene formations. The porous aquifer in Quaternary deposits is unconfined in shallow depths while in greater depths becomes confined. The water level elevation ranges from 60 m to 70 m.

Irrigation hose in a field at Thiva.

According to the Census of 2011, the permanent population of Thiva municipality is 36,477 residents while the permanent population of Thiva town was 22,883 residents. The agricultural sector represents one of the most important economic activities of the region, covering most of the total available land surface. Potatoes, carrots,onions and wheat are mainly cultivated in the plain area. For this reason, groundwater is mainly used for irrigation purposes and secondary for domestic purposes. In particular, local growers own outnumbered deep boreholes with depths ranging from 80 to 300 m. The use of fertilizers and pesticides is prolonged and intensive farming methods, such as ploughing and harvesting, are visible in the whole area. For this reason, a strong pressure posed to groundwater is nitrification and nutrient contamination.