Tourism water demand modelling in Mediterranean cities under current and future climate

Even if tourism represents only a fraction of water consumption at the global scale, in some regions such demand may represent a critical share. The Mediterranean coast is an emblematic case, since it receives many millions of visitors in summer, when rainfall is scarce and there is competition with water demand for irrigation. Many important tourism locations face permanent limitations or temporary restrictions on urban demand due the occurrence of drought events, including the last one in 2022. As the climate changes, water scarcity events have become more frequent and the need for addressing tourism water demand, starting from its understanding, has become a priority. The study presents analyses carried out in two important beach tourism cities (Rimini, in Italy, and Benidorm, in Spain), where water demand models were developed and validated over historical data and then applied for future climate scenarios. Two modelling experiments were carried out: - Modelling of monthly water demand at municipal scale, through implementation of non-linear (stepwise linear regression) and non-linear (based on parsimonious architectures of artificial neural networks) models for the Rimini urban area; - Modelling of hotels water demand: the monthly consumption series of the hotels in Benidorm were averaged to obtain the time series of a "typical hotel”, modelling was carried out and its performance assessed also in relation to the anomalous pandemic years 2020 and 2021. In both types of model implementation (municipal and hotel scale), the input variables included climatic factors (monthly precipitation, number of rainy days, maximum and minimum temperatures) and socio-economic factors (in particular indicators on tourist attendance, resident population and tariff, where available). Finally, a set of 10 EC-JRC raw and bias-corrected Euro Cordex climate simulations were processed and validated against local ground observations on the control period; the corresponding rainfall and temperature series simulated for the future decades (up to 2100) under the RCP8.5 scenario were then used in input to the water demand models in order to analyse the impact of expected climate change on the water demand.