The implications of water storage for human settlement in Mediterranean waterless islands: The example of Pantelleria

Abstract

Consistent water supply is a common issue in the history of Mediterranean civilizations, where hydraulic solutions, such as cisterns, wells, reservoirs and aqueducts, were adopted for private and public supply. In this context, the island of Pantelleria, where surface freshwater is virtually non-existent, represents a unique case for understanding human-environment interaction in waterless environments. Here, in historical times, year-round water supply was only possible through the storage of rainwater in underground cisterns. An intensive field survey carried out across the island led to the discovery of hundreds of cisterns dated from the Punic and Roman periods to the present day. The study of the spatial distribution of the cisterns was compared with archaeological data on the island to gain new insights on historical settlement and demographic patterns. The present work focusses on a semi-quantitative assessment of water storage on the island of Pantelleria based on the evaluation of potential volumes of stored water for different periods. Data available for cisterns in Pantelleria have been analysed and compared with those from coeval Mediterranean regions. Calculations on the seasonal fluctuation between water demand and supply have been estimated to evaluate the efficiency of such system for sustaining human population and subsistence activities through time.

Modelling the freshwater supply of cisterns in ancient Greece

“…Based on these factors and figures we use a slightly more conservative loss factor of 20% to account for a rougher terracotta surface in antiquity than today and loss of water from spill and leakage during transportation. The same figure was used by Mantellini (2015) for the study on Pantelleria.…”

“…Farreny et al 2011;Lange et al 2012) andancient cisterns (e.g. Garbrecht 2001;Connelly and Wilson 2002;Mantellini 2015). The water collection surface is typically a roof-top from which the water is led through pipes and conduits to the cistern.…”

“…In Paris and London in 1823, 14.1 l was used per individual per day, and in Liverpool in 1835 it was16.6 l (Hodge 2000b, adapted from Forbes 1955. Mantellini (2015) approaches the consumption from the other end, and calculates the possible daily consumption volume based on the modelled annual volume collected by the cistern to arrive at 36 l per day per household.…”

“…The situation was, therefore, not representative for how cisterns were used in domestic contexts where the vast majority are found (Klingborg 2017). In a study from the island Pantelleria, located southwest of Sicily, Mantellini (2015) discusses the use of ancient cisterns to supply freshwater in a waterless environment using a model set up similar to Connelly and Wilson (2002). Mantellini's work is based on a model that uses average monthly rainfall values and a static catchment surface based on the oldest dammuso, a traditional rural living unit, on the island.…”

The “jardinu” of Pantelleria as a paradigm of resource-efficient horticulture in the built-up environment

“…Altogether, these aspects have concurred to an uncommonly high biocultural diversity and to the identity of the island itself. Due to the lack of fresh-water sources or wells, water provision for human and agricultural usage on the island is only through water harvesting, and a widespread system of facilities reached a full development as early as the Punic ages (Mantellini, 2015). Rainwater harvesting is shaping every aspect of human activity on the island: there are almost 500 cisterns for storing rainfall storage, and architectural elements for home roofs and gutters especially suited for conveying the rainfall give birth to the typical dammuso houses, easily recognizable Pantelleria icons.…”