Measurements, representations and projects

The pre-19th century topography of Umbria shows its network of water courses very well indeed and highlights how many rivers there were, with some of these being difficult to locate today. These two rare maps by Bernardino Olivieri are highly scenographic scrolls. The Territorio d’Orvieto e Territorio di Perugia map is decorated with an allegory of the town of Perugia and a putto pressing a bunch of grapes – represented by Orvieto – with Lake Trasimeno in the background. Provincia dell’Umbria, the historic Duchy of Spoleto, features an iconographical depiction which echoes Cesare Ripa’s Umbria map.
In 1675 Pope Clement X commissioned Dutch Cornelis Meijer to examine “blockages in the Tiber river bed between Rome and Perugia, and potential solutions for these.” In fact navigation on the river had been jeopardised in some sections by mills and other human activities, ruins of bridges and other buildings as well as material which had accumulated in it after floods. Meijer’s work was only partially used but was the basis for further studies. At the same time, the issue of what to do about the problems generated by floods and river and canal erosion of roads was increasingly pressing. The economists taking part in the debate included Perugia’s Leone Pascoli and the many technicians, surveyors, engineers and architects involved included Francesco Tiroli, Andrea Chiesa, Bernardo Gambarini, Paolo Posi and Pietro Ferrari. The 1818 Del regolare le acque della Valle spoletina […] treatise and the never implemented 1825 project Dell’apertura di un canale navigabile che dall’Adriatico, a traverso dell’Italia sbocchi per due parti nel Mediterraneo to open up a navigable canal across Italy to the Mediterranean were the work of Pietro Ferrari. The plan to channel the Maroggia and Tessino streams which led to land reclamation work in Valle Umbra between Trevi and Spoleto, on the other hand, dates to 1828 and was the work of engineers Girolamo Scaccia and Clemente Folchi. To tackle the problem of erosion by the Topino River on the Via Flaminia road between Nocera and Ponte Centesimo, Paolo Posi suggested building a new road from Foligno through Perugia and Gubbio, to link up with Via Flaminia at Ponte Riccioli.
The exhibits illustrate the extent to which the Arno and Tiber river basins were treated as a single entity throughout the 18th century with Lake Trasimeno in the centre.
The need to regulate relations between the Papacy and the Grand Duchy became clear in the mid-18th century, both where borders in the lake area were concerned and in water control terms, and the two states set their technicians the task of coming to specific agreements on these matters. It was the Water Governance agreement signed in 1780 at Città della Pieve which enabled land reclamation work on the marshes to begin, as documented in Vittorio Fossombroni’s treatise: Memorie idraulico-storiche sopra la Val di Chiana.
It was the Marmore Waterfalls, “Catadupa Velini” and the Velino, Nera and Tiber river systems which were the focus of interest in the Terni valley.