Understanding subterranean grain storage heritage in the Mediterranean region: The Valencian silos (Spain)

Abstract Underground space has widely been used through history, provided either by natural or by dug cavities that were used as storage for farming production. In particular, cereals have constantly been present in the Mediterranean cultures. Their preservation was crucial in the Mediterranean grain trade for local and urban growth. The main goal of this multidisciplinary study is to analyse the typological and architectural characteristics of underground Mediterranean granary structures. It also discusses the excavation process for building a silo, focusing in a study of the Valencian silos at the Spanish Mediterranean shore. The Valencian silo-yard was essential for the socio-economic city development in the 16th century. This is the first research performed on this subterranean ensemble, by searching through historical documents and using a non-destructive technique (NDT) as Ground Penetrating Radar (SIR-3000, GSSI) with 100 MHz and 400 MHz antennae. The composition soil was obtained for hydrogeological characteristics by geotechnical tests. Besides, laser scanner and GPS surveys were carried out for mapping the silo-yard in detail. Since the Valencian silos are a relevant example of subterranean engineering storage, we were able to carry out a comparative study of significant Mediterranean silos (from Algeria, Italy, Jordan, Malta and Turkey) by reviewing documentation. As a result, these underground spaces share numerous features, as type of terrain, excavation process, geographic location, morphology, dimensions, sealing system, usage, etc. These similar features illustrate that a subterranean grain storage stereotype is present in the Mediterranean region heritage.