Water management in the city of Turin (NW Italy) through a physical-chemical one-year piezometers monitoring

Water management in urban cities also deals with pollution coming from both chemicals and anomalous temperatures due to industrial activities and space heating and cooling systems, may determining the urban heat island effect. This work deals with a constant monitoring of the groundwater quality in the urban centre of Turin (NW Italy). Thanks to the partnership with the Municipality of Turin, some piezometers mainly located in the central and southern part of the city, are being monitored. Sensors measuring in continuous groundwater temperature and pressure has been placed at different depths in piezometers. The different position of the sensors depends on the piezometer depth and on the water level from the ground. During one year-monitoring, a series of field surveys to each of the piezometers has been also conducted and they are still ongoing. These consist of detecting important hydrogeological and chemical parameters such as electrical conductivity, pH, and Total Dissolved Solids though the use of a multiparametric device. Results after one-year monitoring highlight a seasonal increasing of the temperature value of at least 1 °C from autumn to summer, for all the investigated piezometers; except for one of the examined cases, these increasing values are not directly related with the electrical conductivity how should it be; this inverse could be explained considering a complex scenario including chemical pollution. To this regard, piezometers located in the most populated parts of the city, in which more public activities as well as more apartments and vehicular traffic are present, display higher groundwater temperature (e.g., 17.15 - 18.9 °C) than those recorded in more peripheral areas or with fewer buildings and activities nearby (e.g., 14.2 - 14.7°C). These results can confirm how urban activities can have an impact on groundwater quality, especially for the temperature value.