Peter PIŠÚT, Juraj PROCHÁZKA

Váh River near Váhovce and Šoporňa on the plan of J. N. Vizer: contribution to the knowledge of geomorphological effects of a catastrophic 1813 flood

Pišút, P., Procházka, J.: Váh River near Váhovce and Šoporňa on the plan of J. N. Vizer: contribution to the knowledge of geomorphological effects of a catastrophic 1813 flood. Kartografické listy, 2017, 25 (1).

Abstract: This paper analyses in detail a historical river plan covering a section of the lower Váh River near Váhovce and Šoporňa (SW Slovakia). The plan was surveyed in November 1813 and completed in December the same year by the official surveyor of the archbishopric of Ostrihom (Esztergom), Johann Nepomuk Vizer. The plan depicts 8.7 km long reach of the former Váh channel (corresponding to the current 3.4 km river section). As an important natural borderline Váh not only divided the properties of two feudal landlords, but also two different historical counties, as well. Intensive lateral development of the river channel after 1790s falls within a peak of the Little Ice Age. A decade prior to 1813, actively eroding riverbanks were successively destroying local fertile hay meadows and protective embankments. The plan became an important basic document for negotiation between the representatives of Bratislava (Pressburg) and Nitra county. It shows the alternative proposals for the river regulation by means of artificial cutoffs (latin: transfossio). For ease of interpretation, the plan was transformed into the S-JTSK coordinate reference system with a plausible RMS value. The plan also depicts one interesting detail - an erosional floodchannel (over 600 m long), that originated during the largest historical flood in August 1813. The remnant waterbody (so-called kolk lake) was a persuasive evidence of the millenium flood´s strength. The plan with a major aesthetic and informative value gives us an idea of historical river landscape that no longer exists. Váh river had been completely transformed in this reach by construction of the reservoir Kráľová in 1980s.

Keywords: historical map analysis, Váh river, regulation, extreme flood, kolk lake