15 Nov 2023
 | 15 Nov 2023
Status: this preprint is currently under review for the journal HESS.

Flood drivers and trends: a case study of the Geul River Catchment (the Netherlands) over the past half century

Athanasios Tsiokanos, Martine Rutten, Ruud J. van der Ent, and Remko Uijlenhoet

Abstract. Extreme precipitation in July 2021 caused devastating flooding in Germany, Belgium and in the Netherlands, particularly in the Geul river catchment. Such precipitation extremes were not recorded previously and were not expected to occur in summer. This contributed to poor flood forecast and hence to large damage. Climate change was mentioned as a potential explanation for these unprecedented events. Yet, before such a statement can be made, we need a better understanding of the drivers of floods in the Geul and their long-term variability, which are poorly understood and have not been examined recently. In this paper, we use an event-based approach to identify the dominant flood drivers in the Geul and employ a multi-temporal trend analysis to investigate their temporal variabilities, as well as, a novel methodology to detect the dominant direction of a trend. Results suggest that extreme 24-hour precipitation cannot solely lead to floods. Heavy multi-day precipitation is the primary high-flow driver in the catchment and the joint probability of heavy and prolonged rainfall with wet initial conditions (compound event) determines the chances of flooding. Critical precipitation (precipitation that leads to floods) shows a consistent increase in the winter half-year, a period in which more than 70 % of extremely high flows have occurred historically. While no consistent trend patterns are evident in the majority of precipitation and extreme flow trends in the summer half-year, an increasing direction in the recent past is visible.

Athanasios Tsiokanos et al.

Status: open (until 10 Jan 2024)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on hess-2023-263', Anonymous Referee #1, 16 Nov 2023 reply

Athanasios Tsiokanos et al.

Athanasios Tsiokanos et al.


Total article views: 47 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
35 11 1 47 3 0 0
  • HTML: 35
  • PDF: 11
  • XML: 1
  • Total: 47
  • Supplement: 3
  • BibTeX: 0
  • EndNote: 0
Views and downloads (calculated since 15 Nov 2023)
Cumulative views and downloads (calculated since 15 Nov 2023)

Viewed (geographical distribution)

Total article views: 47 (including HTML, PDF, and XML) Thereof 47 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 29 Nov 2023
Short summary
We focus on past high-flow events to identify flood drivers in the Geul catchment. We also explore flood drivers’ trends across various times and develop a new method to detect the main direction of a trend. Our results show that extreme 24-hour precipitation cannot solely lead to floods. The combination of long heavy rainfall and wet initial conditions determines the chances of flooding. Precipitation that leads to floods increases during winter, while no consistent trends are found in summer.