The marble plaque is located on the outside right wall of the porch of S.Bartolomeo church and marks the Tiber water level reached during the 1870 flooding. The plaque is highly damaged and only with difficulty it is possible to read: "ALLUVIONE DEL DECEM 1870" [Flooding of Decem 1870]. The flooding of December 29th 1870 has been the highest in the last 350 years and reached a 17.22 meters level, as recorded at Ripetta Hydrometer. The embankment construction caused an increasing of the flooding levels as measured downstream Ripetta due to the obstructed river water downstream St.Paolo, contained by the new banks; it is so explained why the plaque indicating the 1870 flooding level (17.22 at Ripetta) is about 40 cm lower than the 1937 one (16.90 at Ripetta) instead of 53 cm higher.