Author(s): He Qing Huang; Gerald C. Nanson
Linked Author(s): He Qing Huang, Gerald Nanson
Keywords: No Keywords
Abstract: A mathematical analytical approach proposed by Huang and Nanson (2000) is examined against a wide range of flow conditions in order to provide a convincing explanation for the mechanisms governing alluvial channel-form adjustment. Here we show that the extremal hypotheses of MSTC (maximum sediment transporting capacity) and MSP (minimum stream power) are inherent in laws governing alluvial channel flow and that MSTC and MSP are the complementary expressions of a unifying principle – that of MFE (maximum flow efficiency). Importantly, conditions that limit the application of MFE are illustrated and it is shown that in most cases maximally efficient straight channels mathematically derived from basic flow relationships are highly consistent with ‘regime theory'observations from stable canals and observed bankfull hydraulic geometry relations from natural channels. Finally, it is argued that MFE should be regarded as a general principle for understanding alluvial channel-form adjustment because it is the product of the widely applied variational principle of least action and the principle of energy conservation for sediment transport.
Year: 2001