A preliminary assessment of hydrogeological features and selected anthropogenic impacts on an alluvial fan aquifer system in Greece

An investigation was carried out to delineate the hydrogeologic framework and to understand groundwater quality of the Kompsatos River fan aquifer system, northeastern Greece, as well as to assess environmental impact induced by human activities. As groundwater is the only major source of water in this area, it is important to know the effect of geological formations, and anthropogenic activities on groundwater chemistry and environment. A thorough hydrogeological study was performed during the period 2004–2007. The differential river gauging method was used for estimating the volume of water leaking from (or discharging into) the river. Groundwater samples were collected from 89 monitoring wells, during the summer period of 2007, and analyzed for major ions and trace elements. A potential reservoir of groundwater is formed within the Kompsatos River fan. The aquifer system/Kompsatos River interaction is the outstanding feature of this area. Ca–Mg–HCO3–SO4 is the dominant water type as a result of dissolving carbonate salts. B, Ba, Mn, Li, Sr, and Zn are the most abundant trace elements in groundwater. Both the major-ion chemistry and trace element enrichment of the groundwater are controlled by mineral dissolution and water–rock interaction. Nitrate contamination of groundwater is related to agricultural practices. An improperly constructed drainage system led locally to salinization of groundwater. Channelization has caused considerable disruption to the river ecosystem. The eventual construction of a dam on the river will adversely affect the environment and the aquifer system. The lack of managerial policy for water is putting environmental resources and water supply in jeopardy.