A natural phenomenon in Hungary could slightly shrink the country!

A striking—and at the same time instructive—natural process is currently taking place in Hungary: a new oxbow lake could soon form at one of the Ipoly River’s bends in the Hont region. This change is not only a scenic curiosity but also of geographical significance, as this section of the Ipoly forms part of the Hungarian–Slovak border. If the river cuts through its own bend, the tiny new island is likely to end up on the Slovak side, meaning Hungary’s territory could shrink ever so slightly.

How the river moves if left alone

The Ipoly is one of the few rivers in Hungary that has not been heavily regulated: it has no significant channel straightening, concrete embankments, or weirs. As a result, the river still meanders naturally, winding its way across the landscape. Water alternately erodes one bank and then the other, forming new bends over time.

This process, however, has almost completely disappeared on the Danube and Tisza. In the 19th century, river regulation “straightened” nature: rivers were contained to occupy less land, facilitate navigation, and reduce flooding.

But this comes at a cost.

Why it’s problematic to confine rivers to concrete channels

Researchers at the Budapest University of Technology and Economics’ Department of Hydraulic and Water Resources Engineering, including scientific associate Gergely Török, have been studying the Ipoly’s sediment balance and riverbed formation for three years. According to them, Hungary’s major rivers now face a significant sediment deficit caused by regulation, Telex reports.

If the banks are protected from the water, the river cannot wash away natural sediment and must compensate from its own bed. This leads to the riverbed lowering, which can result in:

• Lower water levels
• Increased drying
• Ecological damage