Italy’s terrestrial border unwinds for a total length of 1,913 km, mostly following the line of the natural watershed across the entire Alpine range. On rocky ridges and stable terrains, its contour is materialised through 8,043 boundary stones and metal plaques. On the snowfields and perennial glaciers that shape the watershed at higher altitudes, where permanent physical markers would be impossible, the only trace of the border is preserved in the official maps published by Istituto Geografico Militare, Italy’s national mapping agency.
The border’s path derives to a great extent from the provisions of the Treaty of Peace signed by Italy in 1947, after the end of the Second World War. Its short history reflects many facets of political developments in 20th-century Europe. While the border between Italy and Switzerland has not undergone great changes since the beginning of the 19th century, the one between Italy and Austria was extensively redrawn by the battles of the First World War and the one with France was altered by a number of “minor” territorial cessions at the end of the 1940s following the defeat of Fascist Italy in the war. The frontier with Slovenia, finally, is in fact the same as the one that separated Italy and Yugoslavia after 1954, the year when the Free Territory of Trieste ceased to exist.
Over the course of the last twenty years, almost every physical trace of these borders seems to have faded away: the frontiers that run through the Alps have undergone notable changes in their role and their nature. Up until the end of the last century, they defined a broad spectrum of international relations: from the friendly ties with France and Austria (NATO allies) to mediation with the economic and political enclave of Switzerland and the tightly-sealed border with the former Yugoslavia—de facto, the southernmost edge of the Iron Curtain. This scenario, today, seems to be a forgotten landscape, covered with the dust of the past.
The need for an accurate measurement of the national border has constantly driven the progress of technologies for spatial representation, from the early photogrammetry surveys of the 1920s, to the creation of trigonometric networks, to the final transition to digital co-ordinates of high-accuracy GPS measurements.
Since 1850, Alpine glaciers have experienced a 50% decrease in overall extension. Furthermore, the rate of shrinkage tripled between the 1970s and 2000. Cyclical variations of the ice surface have accumulated into permanent shifts and alterations of the glacier geometry, causing significant drifts of the watershed line and, as a result, the coinciding national borders.
As a consequence of the progressive retreat of the glaciers, the Alpine watershed has undergone considerable displacements in recent years, making it necessary to renegotiate the terms of the boundary between Italy and the adjoining states. The shift in the line of the watershed can take place both in altitude (when a glacier thins or disappears, allowing the emergence of the ridge of rock underneath, which therefore becomes the new and definitive dividing line), and on the surface (slippage and retreat of the glacial basins that result in a modification of its course).
The main European watershed runs across the Alpine region, organising and dividing the continental river network into drainage basins and river catchments. Although this feature demonstrates topography as a system with an organised hierarchy, it is often difficult to discern on the territory, as it can correspond to different elements, such as mountain ridges, passes, valley floors, wetlands, or underground culverts. As a continuous, uninterrupted line, it therefore exists primarily on a map, rather than being an indisputable element of the territory.
Early observations by the Istituto Geografico Militare acknowledged the problematic uncertainty of the limits between Italy and its adjacent countries. A new definition of movable border was eventually achieved through a 2006 agreement between the governments of Italy and Austria and a law concerning the frontier with Switzerland, approved by the Italian Parliament in 2009. Since 2008, the Istituto Geografico Militare has been carrying out campaigns at high altitude every two years to detect any (irregular and unpredictable) shift in the borderline and update the official maps.
The Italian Limes project started in 2014 with a survey of a 1-km section of the Austrian-Italian border at the foot of Mount Similaun, in the Ötztal Alps. A network of five GPS probes were installed on the ice sheet of the Grafferner glacier, following a significant shift in the border measured by the Istituto Geografico Militare in 2012. The sensors tracked the movements of the border throughout the Spring and Summer, until they were buried by new-fallen snow in late September 2014.
On April 2nd, 2016, a new expedition has been carried in order to measure with newly designed instruments the same stretch of the border that had been studied during the previous phase of the project. A new set of sensors has been installed under the guidance of representatives of the CGI (Italian Glaciological Committee) and geophysicists from the OGS (National Institute of Oceanography and of Experimental Geophysics).
The measuring units are arranged into a grid that covers a 1sqm area across the watershed, and they provide data for a precise description of the border’s shifts by detecting any change in the altitude of its points. Additional measurements were done on the site during the expedition, and a geophysical survey of the glacier was performed. These data, along with feeding the art installation with a live representation of the border, will help to better understand the climate change dynamics on the Alps during Spring and Summer 2016.
The measuring units installed on the glacier are solar-powered devices based on an Arduino microcontroller. They have been designed to record precise altitude measurements and a series of other environmental data, useful to understand their location and the weather conditions on the glacier. Their data are processed remotely in order to monitor any change in the glacier surface, detecting in real time the evolution of the watershed geometry.
Data is recorded internally and transmitted every two hours through a GPRS/GSM network provided by TIM. The data received from the sensors are translated into a live, automated representation of the shifts in the border by the drawing machine in the installation. During the design phase, the sensors were tested at -30°C inside EuroCold Laboratories’ facilities at the University of Milano–Bicocca.
The Italian Limes installation is composed of three main elements organised along a linear structure: a raised-relief model of the glacier case study; a collection of unpublished documents and maps from the archives of Istituto Geografico Militare; a drawing machine that allows for a real-time representation of the Austrian-Italian border.