Flow trends in Western Hungary

Knowledge of available water resources is essential in water management and water policy. In accordance with the EU Water Framework Directive, Hungary reviews and updates its assessment of water balance through the River Basin Management Plan (RBMP) every 7 years. In many cases, the available water resources in the RBMP for small streams are based on expert judgment, since it is not always possible to measure the actual water level or discharge. Consideration of climate change and its effects is also a big question: what are the effects of these changes on small streams, and is there a trend in the runoff?

For water managers, water scarcity and abundance are major concerns. To address this issue, our study focused on high-flow and low-flow signatures. This paper presents flow trends during the last 36 years in Western Hungary. During the period 1980-2016, daily discharge measurements were collected at 74 small streams. Twelve flow signatures were selected for trend analyses. Trends were determined for three time periods: the full measured time period at each station, and two eighteen-year periods between 1980-1998 and 1999-2016. At each location, trends were determined with 10% significance using the Mann-Kendall test.

The results show that in the low-flow signatures, no significant changes in flow trends occur at the individual watershed and regional scales during the two eighteen-year time periods, as well as during the full time period. In contrast, high-flow signatures have significantly changed for all three time periods, at both the individual and regional scales.

This work was undertaken as part of a project funded by the EFOP-3.6.1-16-2016-00017.