As part of my Marie Curie research project, I am currently developing a historical GIS of water uses in the Po Valley, 1860 to the present. This includes hydroelectricity, irrigation canals, urban waterworks, and so forth. It’s a lengthy – and sometimes tedious – process, which involves digitizing and geo-referencing a considerable amount of different sources: archival records, grey literature, historical cartography, and aerial photography. The historical GIS, however, has proved to be an invaluable tool to analyze the transformation in direction and uses of water flows that is the focus of my investigation.

Among other interesting functions, a historical GIS permits mapping temporal sequences in space. Last summer, I produced a few temporal sequences about the diffusion of hydroelectricity in the Po River basin from 1880 to 1970, which I presented at the 2nd World Congress of Environmental History in Guimarães, Portugal. More recently, I have been developing another part of the HGIS, concerning sanitation in the Po River basin from 1800 ca to 1940. Here is a little experiment in animated map visualizations which draws on data about aqueducts:

Please note that this is just a sample from a much richer database. Moreover, the visualization I present here is a work in progress. I plan to elaborate more on these and other related data, such as the kind of water intake used, the presence of sewages, the number of inhabitants, or the interaction between urban water cycles and agriculture. That said, it is interesting to compare the above visualization with the result of a simple Ngram search of the word “risanamento” (sanitation in English) in Italian sources between 1800 and 1940:

A first, remarkable surge in the use of “risanamento” that starts around 1880 was followed by a second surge around 1920. This periodization corresponds to the findings of historiography on urban sanitation in Italy, and overlaps largely with the periodization of aqueduct building in cities and towns of the Po watershed as revealed by the above map sequence.  What the Ngram cannot show, however, is the spatial dynamics of this process, and the extent to which it involved not only  major urban settlements but also small country towns and villages. HGIS can help visualize that.