THE PO DELTA IN THE ANTHROPOCENE

The Po Delta is one of the most important anthropogenic river deltas in Europe and the largest in Italy, covering 180 km² and hosting hundreds of animal and plant species. For these reasons, in 1999 the Po Delta was inscribed on UNESCO’s World Heritage List. However, the history of this area is extremely complex and intersects with a series of anthropogenic interventions that date back at least to the Porto Viro bypass (Taglio di Porto Viro), constructed by the Venetian Republic between 1600 and 1604. While land-reclamation activities began in the late 19th century, the 1950s and 1960s were characterized by radical changes in land use and extensive reclamation projects. The agrarian reform establishing the Ente per la Colonizzazione del Delta Padano (Authority for the Colonization of the Po Delta) is one example. The authority known as the Ente covered the provinces of Venice, Rovigo, Ferrara, and Ravenna and was established in 1951 to manage agrarian reform in the Delta territories based on the “partial law” (legge stralcio) of the previous year, which applied to selected areas in Italy. That law imposed obligations and restrictions on private land ownership, set limits on its extent, promoted and mandated land reclamation, and supported small- and medium-sized properties. Nevertheless, the tens of thousands of daily and seasonal labourers who lived on the fringes of large capitalist agricultural estates and worked as sharecroppers faced drastic change: legal reforms and expropriation plans eliminated their minimal means of survival.

Alongside issues related to land reclamation and agrarian reform, the Po Delta experienced another drastic intervention in its landscape: methane extraction. Begun in the late 1930s, gas extraction increased from 26 million cubic meters in 1938 to 300 million in 1951; by 1956, in the Polesine region alone, there were 1,351 wells. These wells were usually only 300–400 meters deep and extracted methane mixed with brackish water, which was discharged into separate channels. Because the lifespan of a methane field is eight to ten years, most of these gas-extraction activities were carried out by numerous private companies acting without long-term plans and sometimes without permits.

By emptying underground reserves, voids were created that caused the affected area to sink. This phenomenon, known as land subsidence, lowered the land and the riverbed by as much as three and a half meters over the following decades, making the area more susceptible to seawater intrusion and flooding. As the link between gas extraction and ground sinking became clearer—thanks in part to government commission reports—all natural-gas wells in Polesine were closed between 1962 and 1964. However, the area experienced high levels of subsidence for almost two decades after the closures.