A solution proposal for interpreting the water level data of the Szeged gauge before 1859

Abstract

In the period before the regulation of the Tisza, usual water level monitoring was only conducted at the Szeged water gauge. For the period before 1859, the height of the gauge zero is uncertain, several significantly different height data are known, so the interpretation of the water level data of the time is only possible to a limited extent. In the observation series, a sudden and unusual water level change was observed at the end of May 1840, which may indicate a lowering of the gauge zero. Based on the statistical analysis of the water level data between 1837 and 1853, the water level values before and after 1840 are not equable, they do not come from the same basic population, so the change of the gauge zero in 1840 is indeed probable. Knowing this, the gauge zero can be reconstructed for the period up to 1837, which can also be verified with the height data of the river surveys of the time.