The Influence of Spatial Variability of Width Functions on Regional Peak Flow Regressions

Gabriel Perez, Ricardo Mantilla, Witold F. Krajewski

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

The authors investigated the relation between the width function and the regional variability of peak flows. The authors explored 34 width function descriptors (WFDs), in addition to drainage area, as potential candidates for explaining the regional peak flow variability. First, using hydrologic simulations of uniform rainfall events with variable rainfall duration and constant rainfall intensity for 147 watersheds across the state of Iowa, they demonstrated that WFDs are capable of explaining spatial variability of peak flows for individual rainfall-runoff events under idealized physical conditions. This theoretical exercise indicates that the inclusion of WFDs should drastically improve regional peak flow estimates with a reduction of the root mean square error by more than half in comparison with a regression model based on drainage area only. The authors followed the simulation with an analysis of estimated peak flow quantiles from 94 stream gauges in Iowa to determine if the WFDs have a similar explanatory power. The correlations between WFDs and peak flow quantiles are not as high as those found for simulated events, which indicates that results from event scale simulations do not translate directly to peak flow quantiles. The spatial variability of peak flow quantiles is influenced by other physical and statistical processes that are also variable in space. These results are consistent with recent work on event-based scaling of peak flows that shows that the spatiotemporal variability of flood mechanisms is larger than the one expected from geomorphology alone.

Original languageEnglish
Pages (from-to)7651-7669
Number of pages19
JournalWater Resources Research
Volume54
Issue number10
DOIs
StatePublished - Oct 2018
Externally publishedYes

Funding

This study was supported by the Iowa Flood Center. W. F. K. also acknowledges the support of the Rose & Joseph Summers endowment. The authors would like to thank Grzegorz Ciach for his helpful comments and the three anonymous reviewers for their insightful observations and editorial suggestions. The WFDs, simulated peak flows, and peak flow quantiles used in this study can be downloaded from https://github.com/gjperez/WFD_WRR_Paper.

Keywords

  • drainage network
  • peak flows
  • regional regression analysis
  • width function

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