Theoretical assessment of changes in design flood peak of an overland plane for two opposing urbanization sequences
✍ Scribed by Tommy S. W. Wong; Yunjie Li
- Book ID
- 101283366
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 224 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0885-6087
No coin nor oath required. For personal study only.
✦ Synopsis
By considering urbanization on an overland plane as a process whereby a relatively rough, permeable surface is gradually replaced by a relatively smooth, less permeable surface, the eect of urbanization sequence on the ¯ood peak is theoretically assessed by the kinematic wave method. In the assessment, two opposing urbanization sequences are considered: one from downstream to upstream, and the other from upstream to downstream. The assessment is carried out in terms of the individual eect as well as the combined eect of the Manning resistance coecient and the runo coecient. For both urbanization sequences and for all degrees of urbanization, the assessment shows that surface conversion from rough to smooth, or from permeable to less permeable causes the ¯ood peak to increase. A comparison of the individual eects shows that for equal reductions in surface roughness and permeability, the reduction in permeability causes greater increases in the ¯ood peak compared with the reduction in surface roughness. For a partially urbanized plane and for the same degree of urbanization, due to the partial area eect, urbanization at the downstream end generally causes greater increases in the ¯ood peak. In terms of urbanization sequence, the downstream to upstream urbanization sequence generally causes greater increases in the ¯ood peak. The eect of urbanization sequence on the ¯ood peak, however, is only signi®cant for the larger reductions in surface roughness and permeability. Finally, a comparison of the results of this study with those obtained from drainage basins shows that for most of the results from the basins, they correspond to those for the small reductions in surface roughness and permeability on an overland plane. For these cases, the eect of urbanization sequence on the ¯ood peak is small.