Song, Song and Schmalz, Britta and Xu, Y. P. and Fohrer, Nicola (2017):
Seasonality of roughness - the indicator of annual river flow resistance condition in a lowland catchment.
In: Water Resources Management, pp. 3299-3312, 31, (11), DOI: 10.1007/s11269-017-1656-z, [Article]
Abstract
Accurate estimation of flow resistance restricts the quality of the hydraulic model performance. In this study, we try to investigate the seasonal dynamic of the Manning’s roughness coefficient (n) based on the one-dimensional hydraulic model HEC-RAS in a German lowland area. We set up four river section models based on the 1 m digital elevation model and field measurements, in which the seasonal roughness factors were calibrated and validated with the gauge record. The results revealed that: 1) the Manning’s n varied from 46% to 135% from the base value in autumn; 2) adopting the seasonal roughness factor improved the quality of the model output; 3) the vegetation condition and water elevation dominated the Manning’s n in summer (April–September) and winter (October–March) half year respectively. Water temperature increased the flow resistence in winter half year; 4) the peak value of Manning’s n appeared in late summer due to the highest biomass, while the minimum roughness occurred in early-spring because of the combined influence of low biomass, high water level and relatively higher temperature. The involvement of seasonal roughness factor improved the model performance and the results are comparable to the previous research of the same area.
| Item Type: | Article |
|---|---|
| Erschienen: | 2017 |
| Creators: | Song, Song and Schmalz, Britta and Xu, Y. P. and Fohrer, Nicola |
| Title: | Seasonality of roughness - the indicator of annual river flow resistance condition in a lowland catchment |
| Language: | English |
| Abstract: | Accurate estimation of flow resistance restricts the quality of the hydraulic model performance. In this study, we try to investigate the seasonal dynamic of the Manning’s roughness coefficient (n) based on the one-dimensional hydraulic model HEC-RAS in a German lowland area. We set up four river section models based on the 1 m digital elevation model and field measurements, in which the seasonal roughness factors were calibrated and validated with the gauge record. The results revealed that: 1) the Manning’s n varied from 46% to 135% from the base value in autumn; 2) adopting the seasonal roughness factor improved the quality of the model output; 3) the vegetation condition and water elevation dominated the Manning’s n in summer (April–September) and winter (October–March) half year respectively. Water temperature increased the flow resistence in winter half year; 4) the peak value of Manning’s n appeared in late summer due to the highest biomass, while the minimum roughness occurred in early-spring because of the combined influence of low biomass, high water level and relatively higher temperature. The involvement of seasonal roughness factor improved the model performance and the results are comparable to the previous research of the same area. |
| Journal or Publication Title: | Water Resources Management |
| Volume: | 31 |
| Number: | 11 |
| Uncontrolled Keywords: | Manning’s n, Seasonal roughness factor, Hydraulic model, German lowland river network |
| Divisions: | 13 Department of Civil and Environmental Engineering Sciences 13 Department of Civil and Environmental Engineering Sciences > Institute of Hydraulic and Water Resources Engineering 13 Department of Civil and Environmental Engineering Sciences > Institute of Hydraulic and Water Resources Engineering > Engineering Hydrology and Water Management |
| Date Deposited: | 31 Jul 2018 06:45 |
| DOI: | 10.1007/s11269-017-1656-z |
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