In the summer of 2000, during work on the construction of the local water purification plant, an outstanding example of a prehistoric riverside settlement was discovered at Longola di Poggiomarino (NA), a town situated in the upper Sarno valley. This extended across the circa 7 ha entire area that was originally to be the site of the plant, and over adjacent areas. The settlement was occupied from the late middle Bronze Age until the beginning of the 6th century B.C. The site is surrounded by low hills on which stand the modern towns of Striano, San Valentino Torio and San Marzano and the great Iron Age necropoli, whose coeval settlements were unknown prior to the discovery at Longola.

From 2001 onwards the settlement, completely submerged by the water-table, was the object of several campaigns of open-area excavation in two adjacent sectors of circa 800 m2 each. So far the investigation has looked at the occupation layers dating from the earliest phase of the early Iron Age (IFe 1A) until the late orientalising period when the site, after having undergone radical structural changes following alluvial silting, was definitively abandoned.

The discovery at Longola has thrown much light on the settlement system of the prehistoric villages on the Sarno plain, a system which demonstrates the capacity of the local community to interact with the natural dynamics of the environment by creating a complex system for the reclamation of the original marshy/swampy environment. To date unknown in southern Italy this consisted in the construction of channels embanked with timber palisades, which aided the drainage of the wet depression. The larger channels were also used for transport, linking the different villages in the valley and, probably the coastal strip, judging by the find inside a sort of wet dock, of two “canoes” dug out of single tree trunks, one of which almost 7 m long. Continuous subsidence in the area necessitated the progressive increase in height of the dry areas, the so-called “islets”, through the raising of floor levels using a system of overlying layers of vulcanoclasts (ashy silts and pumice) for drainage purposes. Brushwood, natural fibre mats and even entire lattice walls from huts damaged by “high” water and then remade on a higher level, were used for waterproofing.

The dry spaces for occupation between the channels were enlarged using a system of fills, mainly constituted by disused timbers and dumps of various materials, including food leftovers and even the waste products from wine making, contained in formwork made of timber posts and planks fixed vertically in the layers of sand. The huts built on these islets were not only residential but were also used for craft-working activities. The finds of numerous metal, bone, glass paste and amber artefacts, often unfinished or unsuccessfully completed, documented flourishing local specialised crafts which made Poggiomarino one of the regions most important centres.

Smelting activity has been documented on the site for the orientalising period by the discovery of a series of furnaces for metal working. Judging by the large number of casting moulds found in the levels of the earliest phase of the early Iron Age this activity was already practised in the preceding period.