Reconstruction of the 1784 flood hydrograph for the Vltava River in Prague, Czech Republic

The flood of February 1784 was one of the most extreme events, not only in Bohemia (present Czech Republic), but across Europe. This paper presents a reconstruction of the 1784 flood hydrograph based on all available, mostly non-instrumental, data. The reconstructed 1784 flood hydrograph, the oldest one available for the Vltava River in Prague, reveals the extraordinary dynamics of the flood. In comparison with the hydrographs of the most disastrous Czech historical floods (of 1845, 1862, 1872, 1890 and 2002), the 1784 flood was a very rapid event. From the onset of precipitation, it took only 45 h for the flood to peak in Prague and there was a ∼ 4 m rise in water level during a 12-hour period. The steep gradient of the rising limb of the flood hydrograph is still a record in Prague and the recorded peak water stage was exceeded only by the flood of 2002. This paper introduces a method for flood reconstruction for the early instrumental period of hydrology and meteorology when the direct measurement of water levels was not widespread. This approach has practical applications for enhanced flood warning systems. An improved understanding of past hydrological extremes may contribute significantly to our understanding of flood dynamics in an era of global change.