Effect of spatial and temporal variability in rainfall and watershed characteristics on stream flow hydrograph

✍ Scribed by V. P. Singh

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 233 KB
• Volume: 11
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/(sici)1099-1085(19971015)11:12<1649::aid-hyp495>3.0.co;2-1

✦ Synopsis

The shape, timing and peak ¯ow of a stream ¯ow hydrograph are signi®cantly in¯uenced by spatial and temporal variability in rainfall and watershed characteristics. Depending upon the size and shape of a watershed, its hydrological response is closely linked with storm dynamics. On an urban watershed a rain storm moving in the direction of ¯ow produces a higher peak than it would if it were moving in the opposite direction. The eect of storm speed on peak discharge is much less for rapidly moving storms than for storms moving at about the same speed as the ¯ow velocity. In a relatively homogeneous watershed the most important eect of spatial variability of rainfall occurs in the timing and shape of the runo hydrograph. Temporally variable rainfall leads to higher peak ¯ow than does constant rainfall. Sig-ni®cant errors in the prediction of runo occur when an equivalent uniform hillslope is used to represent a heterogeneous hillslope. When average soil properties are used instead of spatially variable properties, signi®cant dierences are observed in in®ltration. Spatially variable roughness alters the ¯ow dynamics signi®cantly.