Author(s): A. G. Barnett; C. Hellberg
Linked Author(s): Alastair G. Barnett
Keywords: Residual Flow; Resistance; Catchment Runoff; Floods; Modelling
Abstract: Resistance calibration conventionally assumes a flow profile along the channel, then seeks to match observed level hydrographs by adjusting parameters such as Manning n values. This takes no account of errors in the assumed flow profiles, even though field measurements of flows are more difficult than those of levels. An improved method concentrates attention on flow errors by virtually eliminating level errors, setting the measured levels as boundary conditions at stub tributaries inserted at every profile measurement point. This method achieves calibration by the analysis of residual model flow discrepancies between successive stations, so it is called “residual flow modelling”. Most of these balancing flows can be matched to runoff from the local subcatchment, leaving minimal flow balance errors. Use of this technique is demonstrated by a sample application in an engineering study requiring precise calibration of flow resistance sensitivity to the planting of riparian vegetation.