Assessment of intrinsic vulnerability using DRASTIC model and GIS in Kiti aquifer, Cyprus

Abstract

Approximately 70% of the population of the earth lives in coastal areas and the majority of these people depend on coastal aquifers for freshwater. For this reason the coastal aquifers are vulnerable to pollution and are now recognized as a crucial arena for future progress towards sustainability in world. This paper deals with the assessment of groundwater vulnerability of Kiti aquifer, South Cyprus. The Kiti aquifer, covering an area of about of 30 Km2, is situated in the southern part of Cyprus with a mean elevation of 20 m above sea level. The area is characterized by semi-arid climatic conditions. The groundwater resources are related to the Pleistocene coastal plain and the recent Tremithos river valley deposits. The concept of the groundwater vulnerability is based on the assumption that the physical environment may provide some degree of protection to groundwater against human activities. The DRASTIC method is applied to evaluate aquifer vulnerability. The method was developed by the United State Environmental Protection Agency (EPA), as a technique for assessing groundwater pollution potential, and is based on seven (7) parameters: Depth (D), Recharge (R), Aquifer media (A), Soil media (S), Topography (T), Impact of the vadose zone media (I), hydraulic Conductivity of the aquifer (C). Determination of the DRASTIC index (DI) involves multiplying each parameter weight by its site rating and summing the total. Based on DI values a groundwater vulnerability map was illustrated, using a Geographical Information System (GIS). The highest vulnerability values in the Kiti area, covering a large part, are associated with shallow aquifers without great depth of the vadose zone. The results provide important information and the vulnerability map could be used from local authorities and decision makers who are responsible for groundwater resources management and protection zoning.