Water resources and groundwater quality in North Peloponnesus (Greece)
Groundwater plays an important role for urban and agricultural water supply in northern part of Peloponnesus. Despite increasing environmental awareness in this area, groundwater is a resource that is being stressed. Groundwater provides about 80% the total quantity of water supply. Distribution of water resources is nonhomogeneous in this region. In general the eastern part is semiarid, whereas the western part is supplied with abundant water. Surface water potential in North Peloponnesus estimated to be 0.9- 1.2x109 m3 y-1. Overexploitation of groundwater and the extensive agriculture has created environmental problems in some aquifers (sea water intrusion, nitrate pollution). Seawater intrusion occurs in some coastal aquifers, where negative water balance has been established. High percentage of the examined samples exceeded the maximum admissible nitrate concentration of 50 mg l-1, set by EU for drinking water. Groundwater in urban areas has been contaminated to varying degrees. The water quality is classified into Ca-HCO3 type (fresh water) and Na-HCO3 or Na-Cl type (brackish waters) in the coastal part, due to seawater intrusion. Some recommendations are made in order to safeguard high water quality and to develop new ways of providing water source in the study area. Moreover, an integrated and comprehensive management scheme should be applied, aiming at sustainability of water resources and based on surface water and groundwater exploitation, simultaneously.