IDENTIFICATION OF THE HYDROCHEMICAL FACIES OF THE SPRING WATERS IN THE CRATI RIVER BASIN

Water is the most essential element for the existence of life on Earth, which is becoming increasingly precious during the last decades. In fact, water quality issues are one of the major challenges that humanity is facing in the twenty‐first century considering safe drinking water the basic need for every citizen. About 80% of the diseases in the world and one‐third of the deaths in the developing countries are caused by contaminated water. In particular, the groundwater is the main source for drinking purposes, sanitary uses, irrigation, and industrial processes. A good management of this resource is very important especially in some areas such as the Mediterranean basin, which is located in a transition zone between North Africa (arid climate) and central Europe (temperate and rainy climate), which is affected by the interaction between mid latitude and tropical processes and which can be considered as potentially vulnerable to climatic changes. In fact, groundwater quality is getting deteriorated also due to climate changes which cause low rainfall and high evapotranspiration. Groundwater quality in a region largely depends on natural processes, like dissolution and precipitation of minerals, groundwater velocity, quality of recharge waters and interaction with other types of water aquifers, and weathering and catchment erosion, and on anthropogenic inputs including urbanization, agricultural, and industrial activities. Among the natural factors, geology of the catchment area, degree of chemical weathering of the various rock types, and inputs from sources other than water‐rock interaction play a significant role in controlling the chemistry of the water. Within this context, the knowledge of water resources quality and in particular of natural spring waters represent a fundamental step for both their use and preservation. In order to achieve these purposes, extensive surveys are needed, at basin scale, to identify both the location and the size of the spring waters, but even more to identify the hydrochemical facies of the aquifers. This work shows the results of an investigation campaign which allowed the identification and sampling of more than 200 spring waters falling within the Crati river basin, the largest basin of the Calabria region (southern Italy). The collected samples were analysed from a chemical‐physical point of view and the data were implemented in a geo‐database. Several physical and chemical parameters were analysed and the Langelier‐Ludwig diagram was built to evaluate the hydrochemical facies of the sampled waters. Results evidenced that the majority of the sampled spring waters falls within the first sector and the fourth sector of the diagram, corresponding to bicarbonate alkaline‐earth waters and chloride‐sulphate alkaline‐earth waters, respectively. These results reflect very well the global lithological environment of the study area, which is mainly constituted of calcareous and carbonatic rocks and intrusive magmaticor metamorphic rocks. Additionally, the relationships between water temperature and altitude and electric conductivity and altitude were assessed. As a result, a slight downward behavior of the conductivity with the elevation and a marked reduction of the spring water temperature with elevation have been detected. This latter result denotes superficial aquifers in which water temperature is affected by air temperature. In fact, temperature can be used as a tracer of hydrologic and flowing processes for natural spring waters.