Integrating hydrogeological and economic analyses of groundwater flooding in an urban aquifer: the plain of Naples (Italy) as a case study

ABSTRACT

The study applies the defensive expenditure approach via hydrogeological data for a sector of the plain of Naples to value the economic damages produced by groundwater flooding on private properties. It follows from the integrated analysis that the value of the economic damages is increasing over time at a compound pace. The over-pumping of groundwater during the industrialisation period, and its stop in the subsequent de-industrialisation one, impaired the long-run natural equilibrium of the groundwater resources. Thus, the myopic decisions taken with respect to land and groundwater use, and a short-sight urban design planning have caused increasing economic costs in the medium and long terms.

KEYWORDS:

• Groundwater
• flooding
• defensive-expenditure
• Naples
• Italy

Acknowledgments

The authors wish to thank Mr. Antonio Esposito for the expenditure data provided. The field activities were undertaken and funded within the Research Agreement ‘Studio delle dinamiche idrogeologiche delle falde di Casalnuovo di Napoli’ signed in June 2013 by the municipality of Casalnuovo di Napoli and the Department of Earth, Environmental and Resources Sciences, University of Naples Federico II. Elisabetta Marzano gratefully acknowledges financial support from the University of Naples Parthenope, Department of Economic and Legal Studies, project CoRNDiS, DM MUR 737/2021, CUP I55F21003620001.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1. https://land.copernicus.eu/pan-european/corine-land-cover, last accessed 23 November 2019.

2. The data are taken from the bookkeeping records provided by the administration of the building.

3. Electricity bills are bimonthly as customers are charged for consumption in the two previous months. For this reason, the explanatory variable, the piezometric level, is two months lagged.

4. For a representative apartment of the selected building, we collected the market price at two different times, namely 2010 and 2020. The property value has declined sharply from €1800/m² in 2010 to €1400/m² in April 2020. Unfortunately, we cannot determine to what extent the observed decline (about 22% in 10 years) is traceable to the consequences of groundwater flooding. But, it is possible to recognise the market consequences of the property value reduction caused by groundwater flooding by comparing the prices recorded in 2020 in the representative ‘La Palma’ building with those prevailing in the Casalnuovo di Napoli municipality, as recorded by two different sources of data: (i) dataset of property values (Italian Revenue Agency); (ii) the housing advertisement website immobiliare.it. We found that the average loss for households suffering the impact of groundwater flooding on their residential property is non-negligible, ranging from a −9.4% to a peak of −35.7% of the property value, depending upon the reference quoted.