The Poiseuille and Darcy laws describe the velocity of groundwater flow under laminar conditions. These laws were deducted empirically in conduit and porous systems, respectively, and are widely used to model the groundwater flow. The analytical relationship between these hydraulic laws has been found by draining a tank-reservoir. Based on equations found, the discharge in a conduit under the Poiseuille law can be transformed in the same amount flowing inside a darcian system, and vice versa. This transformation occurs, for example, in karst aquifers, from the matrix to karst conduits during discharge phases, and from conduits to matrix during recharge phases.

The hydraulic phenomenon of upwelling groundwater flow affecting the karst area of the Grassano-Telese springs (southern Italy) has been investigated through piezometric measurements, discharge, and chemical–physical monitoring of springs, radon activity included. Locally, both large karst springs and sulfurous thermal springs are closely located, and raise several questions on their origin. In this study, the phenomenon of the upwelling flow is supported by different types of evidences: Amazing density of sinkholes connected to hypogenic speleogenesis processes, constancy of temperature, and hydraulic conductivity of spring water, change of radon activity during the hydrological year, increasing of the hydraulic head with depth. Numerical code provides an estimation of the upwelling phenomenon in an unconfined aquifer feeding the karst springs, using MODFLOW tools. Based on the results reached, the phenomenon of the upwelling flow is able to explain the hydrological processes observed in the Telese karst area.

The upwelling groundwater flux has been investigated by deep piezometers in a spring area characterized by alluvial deposits covering a karst substratum in Southern Italy. The piezometers are of varying depth located in a flat area. They have been monitored for a long period (about 40 years), and when measured, a good relationship between spring discharge and hydraulic head was observed. The local upwelling groundwater flux has been deducted by the increasing of the hydraulic head in depth, which allows the estimation of ascendant hydraulic gradient and groundwater velocity during the dry and wet seasons. A specific analytical solution has been used to estimate the zone involved by the ascendant flow, and could also be used in other spring areas. Some physical and chemical characteristics of spring water have been collected, including the radon (²²²Rn) activity, to support the phenomenon of the ascendant flux. The man geological and hydrogeological features leading to ascendant flux in karst environments is also discussed for some areas of Southern Italy, where many springs are affected.

The need to produce energy from clean energy sources has caused public administrations and private companies to look for suitable places. The windiness detected in the eastern area of the Matese karst massif (southern Italy) has favored the construction of wind farms to produce electricity from clean energy sources. During the installation of the first wind turbines, some alterations in the supply of drinking water, fed by the springs of this area, were attributed by the population to this installation. Therefore, in order to assess whether there has been an impact produced by the wind farms on the quality of groundwater, a detailed hydrogeological study was developed. Karst hydrogeological features of the area were mapped, focusing on endorheic areas, sinkholes and karst springs. Artificial tracer tests were then carried out to investigate groundwater flow circulation and connection between surface karst landforms and springs. Chemical and physical characteristics of the groundwater were monitored during the construction of the wind farms and, for the following months, by infield measurements and laboratory analysis of spring water samples. This study highlights that wind farms mainly develop along the boundary of endorheic areas, which are important recharge zones for groundwater resources, and are directly connected to the major karst springs through sinkholes and a dense network of karst conduits. The results of the monitoring did not reveal any anomalies in the quality of the water and, therefore, any alterations cannot be attributed to the wind farms. Our investigation appears useful for a better understanding of the possible actual and future effects of the wind farms on both groundwater circulation and spring water quality in this karst area.

The hydraulic phenomenon of upwelling, affecting several karst springs of Apennines, has been investigated through piezometric data at different depth and chemical-physical data of springs water. Three different springs in Campania region were analyzed (Serino, Grassano and Caposele springs), characterized by three different groundwater schemes, but with the same upwelling phenomena at the springs. Some data (spring discharge and piezometric levels) have been acquired from the municipal waterwork,. Other data (physical-chemical parameters and Radon values (222Rn)) have been collected ad hoc in spring waters, included the spring discharges of Grassano springs. All the data pointed out that karst springs considered are fed by groundwater flux that locally is vertical. This features, common to others springs of Apennines, can be relevant in the realization of the tapping work, in their maintenance and for the definition of the protection area of the springs.

This short paper aim to provide an analytical approach to pinpoint the recharge processes evaluated for some karst massifs of southern Italy. The assessment of annual mean recharge for thirty time period was carried out for Terminio, Cervialto, Matese and also for Alburni karst massif (1971 - 1999); the annual scale groundwater recharge analysis starts from regression of annual mean values of different ground-elevated rain gauges and thermometers. The estimation takesinto account the presence of the wide endorheic areas (for Matese, Terminio and Cervialto massifs), distinguished from the rest of the catchment, characterized by the “open areas”. For the Alburni karst massif the recharge phenomenon is chiefly controlled by summit karst plateau, where an “internal runoff” occurs; as the complexity of surface orography doesn’t allow to define all endorheic areas affecting karst plateau, in order to define recharge coefficient proposed by Fiorillo et al. (2015) in annual scale recharge model, the summit karstic plateau was considered as a wide endorheic area, representing then the predominant recharge area, feeding basal karst springs.