Impact of stream network structure on the transition break of peak flows

摘要

Theprimary objectiveof this study was to investigatethe cause of the transition break in the scalingrelationship graph of peak discharge vs. drainage area. Watershed geomorphologic and hydrological data from eleven nested watersheds in the Komarovka River Basinin Russia were collected for analysis, Aseries of numerical experiments were conducted using a digital elevation model and a geomorphologybased runoff model to investigate the variation of the upstream drainage areas and peak discharges at specifiedsampling locationson the stream network.The results indicated that when a large tributary flowed into the mainstream. an abrupt increase in the drainage area was observed in the graph of drainage area vs. distance to mainstream outlet. Thereason is that the drainage area of the tributary relativeto the drainage area of the mainstream at the locationwhich the tributary joins in is large.The abrupt change corresponded to the transition break shown in the graph of peak dischargevs. drainage area. which was an indication of the scalingrelationship transferring from linearity to nonlinearity.The cause of the transition break had been verified by using hydrological records obtained from the Komarovka River Basin and successfully simulated by applying the geomorphology-based runoff model.