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Notes on the landscape of Ostia and Portus before 1880

Antonia Arnoldus-Huyzendveld


Towards the end of the 19th century the Italian government planned the final land reclamation of the Roman coastal belt. This activity brought about a rather strong transformation of the landscape, which presently hampers the reconstruction of its original features. One of our fortunes is that, in preparation of the reclamation project, Giovanni Amenduni, chief engineer of the special office for the reclamation of the "Agro Romano", published a precise map of the existing landscape, which can be considered as one of the keys to the reconstruction of the Roman landscape. The map was published in 1880, at a scale of 1:50.000. Moreover, a series of topographical maps was printed, at a scale of 1:25.000, with a 250-meter grid of absolute heights. The height of the planned landfill (mainly applied in the former lagoons) is also given. Recent local checks showed that the altitudes given on the maps do not differ from the modern ones by more than 5 to 10 cm. (a difference which is supposedly due to changes in the geodetic reference points, and not to real changes in the land level).

We present here two details of the landscape map, namely the Trajanic harbour and the area around Ostia.

The form of the Trajanic hexagon is rather degraded. The original outline was in fact restored only in the thirties of the 20th century, during its transformation into a reservoir for irrigational use. Three small ponds are visibile to the south of the hexagon. The pond to the right coincides (but not exactly) with the Trajanic dockyard. The other small ponds are situated outside the Trajanic complex, but within the Claudian harbour. The land use in the northern area is given on the map as agricultural (dark yellow), whereas the southern half was by then used for grazing. This contrast reflects exactly the natural boundary between the loamy Tiber soils and the dry, sandy soils of the dune belt, the latter including both the dunes of Roman times and the deposits related to the post-Roman coastal expansion.

The second detail of the map shows that, towards the end of the 19th century, Ostia was reduced to small hills, hiding the Roman constructions below layers of rubble. But the outline of the original town is clearly visible. Along the main street of Ostia is written "Via dei Sepolcri". The modern building (a small black square) near the Tiber must the Casone del Sale, a store building for salt, possibly built at the end of the fifteenth century (it is now the Museum). Close to modern Ostia one observes a typical "oxbow" lake, denoting the original Tiber course. This meander was cut off from the main course, due to natural processes, during the flood of 15 September 1557. Since then the area is called "Fiume Morto". Although the crescent-shaped lake has been filled in during the land reclamation, the original depression can still be observed in some streets of modern Ostia (e.g. Via S. Massimo). In Roman times the course of the Tiber must have differed slightly from the course just before the disastrous flood. In fact, an outward shift of about 12 meters between the first and sixteenth century was reconstructed from an excavation in the lake area. The sharp curve close to Roman Ostia (which destroyed some of its buildings) represents a partial Tiber shift, which occurred after the flood of 1557 and probably before the end of the seventeenth century.

Notes:
- The red lines are only references for the geodetic measures. The figures are scans of a colour photocopy of the original map, so they may have lost some of the original neatness.
- The original map, scale 1:50.000, measures 35 x 68 cm.
- The original size of fig. 1 is c. 3 x 3 cm., that of fig. 2 c. 4.5 x 4.5 cm.
- The top of the map is oriented towards north-east.

Reference:
- Amenduni, Giovanni (1880): "Sulle Opere di Bonificazione della Plaga litoranea dell'Agro romano, che comprende le Paludi e Stagni di Ostia; Porto, Maccarese (..)", Roma Tipografia Eredi Botta (year of print 1884).

© 1999 Antonia Arnoldus-Huyzendveld


Ostia e il suo castello

Undated engraving entitled "Ostia e il suo castello".
The "oxbow" lake seems to be visible in front of the mediaeval Castle.
Original owned by Jan Theo Bakker.