31 Jul 2023
 | 31 Jul 2023
Status: a revised version of this preprint is currently under review for the journal HESS.

What controls the tail behaviour of flood series: Rainfall or runoff generation?

Elena Macdonald, Bruno Merz, Björn Guse, Viet Dung Nguyen, Xiaoxiang Guan, and Sergiy Vorogushyn

Abstract. Many observed time series of precipitation and streamflow show heavy tail behaviour. For heavy-tailed distributions the occurrence of extreme events has a higher probability than for distributions with an exponentially receding tail. If we neglect heavy tail behaviour we might underestimate rarely observed, high-impact events. Robust estimation of upper tail behaviour is often hindered by the limited length of observational records. Using long time series and a better understanding of the relevant process controls can help with achieving more robust tail estimations. Here, a simulation-based approach is used to analyse the effect of precipitation and runoff generation characteristics on the upper tail of flood peak distributions. Long, synthetic precipitation time series with different tail behaviour are produced by a stochastic weather generator. These are used to force a conceptual rainfall-runoff model. In addition, catchment characteristics linked to a threshold process in the runoff generation are varied between model runs. We characterize the upper tail behaviour of the simulated precipitation and discharge time series with the shape parameter of the generalized extreme value distribution (GEV). Our analysis shows that runoff generation can strongly modulate the tail behaviour of flood peak distributions. In particular, threshold processes in the runoff generation lead to heavier tails. Beyond a certain return period, the influence of catchment processes decreases and the tail of the rainfall distribution asymptotically governs the tail of the flood peak distribution. Beyond which return period this is the case depends on the catchment storage in relation to the mean annual rainfall amount. We conclude that, for return periods that are mostly of interest to flood risk management, runoff generation is often a more pronounced control of flood heavy tails than precipitation.

Elena Macdonald et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on hess-2023-186', Anonymous Referee #1, 28 Aug 2023
    • AC1: 'Reply on RC1', Elena Macdonald, 06 Sep 2023
      • RC3: 'Reply on AC1 : Parallelism of Pct and Q, effect of Cperc, impervious catchments', Anonymous Referee #1, 07 Sep 2023
        • AC2: 'Reply on RC3', Elena Macdonald, 26 Sep 2023
  • RC2: 'Comment on hess-2023-186', Anonymous Referee #2, 06 Sep 2023
    • AC3: 'Reply on RC2', Elena Macdonald, 26 Sep 2023

Elena Macdonald et al.

Elena Macdonald et al.


Total article views: 620 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
469 133 18 620 4 4
  • HTML: 469
  • PDF: 133
  • XML: 18
  • Total: 620
  • BibTeX: 4
  • EndNote: 4
Views and downloads (calculated since 31 Jul 2023)
Cumulative views and downloads (calculated since 31 Jul 2023)

Viewed (geographical distribution)

Total article views: 577 (including HTML, PDF, and XML) Thereof 577 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 28 Sep 2023
Short summary
In some rivers, the occurrence of extreme flood events is more likely than in other rivers – they have heavy-tailed distributions. We find that threshold processes in the runoff generation lead to such a relatively high occurrence probability of extremes. Further, we find that beyond a certain return period, i.e. for rare events, rainfall is often the dominant control compared to runoff generation. Our results can help to improve the estimation of the occurrence probability of extreme floods.