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Hydraulic Causes for Basin Hydrograph Skewness
Author(s) -
Collischonn Walter,
Fleischmann Ayan,
Paiva Rodrigo C. D.,
Mejia Alfonso
Publication year - 2017
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1002/2017wr021543
Subject(s) - hydrograph , skewness , hydraulics , structural basin , hydrology (agriculture) , flow (mathematics) , channel (broadcasting) , base flow , environmental science , runoff model , geology , drainage basin , mathematics , geotechnical engineering , geography , geomorphology , computer science , statistics , geometry , engineering , computer network , cartography , aerospace engineering
It has been suggested that hydrograph skewness depends on the relative dominance between hillslope and channel network transport processes, where the former ones make the hydrograph positively skewed while the latter tends to make it negatively skewed. More recently, however, the role of river hydraulics in shaping the hydrograph has been highlighted. We present a set of numerical modeling experiments using a hydrodynamic model of river networks in which we investigate how channel hydraulics influence the shape of the hydrograph, particularly its skewness. We further investigate the influence of base flow, rainfall intensity, cross section geometry, and basin scale on unit hydrograph response. We show that river hydraulics has a decisive role because positively skewed hydrographs may occur even when water inputs to the river network are negatively skewed, and in catchments whose width function is also negatively skewed. We show additional results related to the effect of the degree of nonlinearity in the relationship between celerity and discharge, the effects of base flow and rainfall intensity. These further confirm that hydraulic factors may be decisive in determining hydrograph shape.