The research project, first prize winner of the 2013 call for research projects on Es Mercadal and Fornells (Ajuntament des Mercadal), analyses the traditional management of rainwater in the municipality of Es Mercadal. The study was carried out at three different scales: that of buildings and cisterns (object), that of the settlement (urban) and that of the cultural landscape (territorial). It demonstrates that the capture, storage and management of rainwater was entirely trans-scalar and transversal, from collecting water on a small roof to transforming the entire island territory into a large-scale hydrological management infrastructure.

In Menorca, for many centuries, cisterns and water tanks enabled people and their animals to survive the severe dry season characteristic of the Mediterranean climate. From mid-May to late August, rainfall drops dramatically, precisely when temperatures reach their annual maximums. This creates significant “water stress”, when organisms need hydration the most and water is least available. All species must therefore seek mechanisms to survive.

This collection and storage of rainwater made it possible to have water during periods without precipitation. Seen this way, all the cases studied transform rain that falls from the sky and escapes quickly into stored fresh water, a vital and highly valued resource. The study concludes that on the island of Menorca, until the second half of the twentieth century, all impermeable and sloped surfaces were used to collect this natural resource. “Not a drop wasted” was the guiding principle, sometimes to almost obsessive extremes.

Traditional water management was not limited to cisterns and tanks. Houses, both urban and rural, towns and even the entire island territory, carefully modified to manage runoff, all formed part of this essential system. The research shows that in traditional Menorca, still very present in many places, all elements of the built landscape (houses, paths, fences, farmsteads, streets, courtyards, squares, threshing floors, dry stone walls…) are in fact small parts of a vast hydrological management infrastructure present in every corner of the island.

The image “Current classification of hydrological units according to the Balearic Hydrological Plan (PHB)” shows the hydrological balance of the Es Migjorn aquifer, prepared by Leticia de la Vega in her Master’s Thesis directed by Professor Albert Cuchí “Analysis of the Menorcan Hydrological Cycle, for a sustainable territorial management”. The diagram clearly shows that most of the island’s annual precipitation (302 Hm3) does not recharge the aquifers, but is “lost” through evapotranspiration (242 Hm3) or surface runoff returning to the sea (9.4 Hm3). It is important to highlight that the rainwater collected by cisterns, buildings and the territory belongs mostly to these two major flows and therefore does not affect aquifer recharge through infiltration.