Uplift Evidences Related to the Recession of Groundwater Abstraction in a Pyroclastic-Alluvial Aquifer of Southern Italy

Abstract

Aquifer mismanagement is a common anthropogenic cause of subsidence and uplift phenomena in alluvial plains, representing one of the main natural hazards in urban areas due to related damage to urban structures and infrastructures. In this work, the groundwater rebound phenomenon that occurred in the last decades of the 20th century in the Lufrano area (Metropolitan area of Naples, Southern Italy) has been studied by integrating geological data, hydrogeological continuous monitoring and spaceborne SAR information derived from ERS-1/2 and ENVISAT satellites. In the period of 1989–2006, the Lufrano area, which hosts an important well field made up of 180 wells extracting groundwater for drinking use, suffered an initial over-exploitation of the aquifer which was followed by a sudden and severe decrease of the volume abstraction, resulting this last in a rapid ground uplift. The coupled analysis of hydrogeological and DInSAR data have shown a correspondence between piezometric level rise (up to 15 m) and ground uplift (up to 50 mm) trends in the period 1989–2006. In order to examine the spatio-temporal evolution of the phenomena and the cause-effect relationships, showing the link between the two phenomena and their rates, longitudinal cross-sections were carried out and comparisons between piezometric level rise and time-series of displacements were reconstructed. The obtained results represent an initial contribution to the definition of ground deformation related to groundwater level rise phenomena, providing a basis for future studies focused on the modelling of the hydro-mechanical properties of the aquifer.

Mapping of uplift hazard due to rising groundwater level during floods

“…These mainly involved an increase in the terrain level and the construction of relief wells at the most endangered locations, namely along the flood protection barriers where the potential seepage path has the smallest length. Unfortunately, it was not possible to verify the results by comparing the uplift effect due to real floods (e.g., in the years 1997 and 2006) with ENVISAT satellite monitoring images (Coda, Tessitore, et al, 2019;Coda, Confuorto,…”

“…Unfortunately, it was not possible to verify the results by comparing the uplift effect due to real floods (e.g., in the years 1997 and 2006) with ENVISAT satellite monitoring images (Coda, Tessitore, et al, 2019; Coda, Confuorto, et al, 2019) because of extensive and frequent civil works and terrain modifications connected with commercial zone construction. Moreover, the floods in 1997 and 2006 did not reach the terrain level behind the levees.…”

Quantitative Assessment of Specific Vulnerability to Nitrate Pollution of Shallow Alluvial Aquifers by Process-Based and Empirical Approaches

“…The results obtained confirm the possibility of the existence of an anomalous concentration of nitrate in groundwater as has been reported in other studies [46][47][48] as well as that current concentrations of nitrate fertilizers in groundwater derive from the cumulative effects of fertilizing practice of the past and transport in the saturated zone. The recognition of the strong control of water table depth on UZT and groundwater vulnerability derives the important hint that groundwater vulnerability can vary in time depending on long-term piezometric fluctuations, which can occur due to natural or anthropogenic causes [58,62,64].…”

“…As an effect of overexploitation, increasingly, deep groundwater has been pumped, causing the decay of its quality due to the rise in nitrates, fluoride, iron, and manganese concentrations beyond the accepted limit for drinking water [60,61]. Therefore, since the beginning of the 1990s, groundwater abstraction for drinking use has been progressively abandoned, causing a groundwater rebound [56] with a rise in piezometric levels in the study area of up to about 16 m, determining the relevant impacts on human activities related to groundwater flooding and ground deformations [58,[62][63][64].…”

Natural and Anthropogenic Groundwater Contamination in a Coastal Volcanic-Sedimentary Aquifer: The Case of the Archaeological Site of Cumae (Phlegraean Fields, Southern Italy)

“…Finally, in the last two decades, the study area has been recognized as affected by hydro-environmental criticalities which endanger the state of conservation of artefacts, cultural remains and ancient monuments of the Cumae archaeological site (Figure 2a,d-g). Indeed, as observed in other sectors of the Metropolitan City of Naples [50,51,67,68], the rising of groundwater level and related Groundwater Flooding (GF) phenomena have been registered, causing damage to structural and decorative features of buried archaeological artefacts. Both hydrological processes are mainly attributed to the rising of sea levels from the Roman period to the present in the central area of Mediterranean basin [69] and to local volcano-tectonic land subsidence [70].…”