An Experimental Study of Manning’s Roughness Coefficient with an Acoustic Doppler Current Profiler (ADCP) Method of the River Ganga at Gandhi-Ghat Site, Patna, India

The accurate determination of Manning's roughness coefficient is crucial in hydraulic studies, especially in open channel flow analysis, as it significantly influences the design of water resources and hydraulic engineering projects worldwide. In the present study, fieldwork or an experimental study is applied to the river Ganga at Gandhi-Ghat site Patna as a case study. The data are measured in the field for the period from 27/04/23 to 26/06/23. This study aims to obtain Manning’s roughness coefficient through the latest developed technique ADCP Method and also to examine its comparative analysis with the current meter method which is a conventional method. However, this conventional method is time, and a skilled person is required to operate the instrument alternatively ADCP is fully automatic and simple to operate. Therefore, the measurement was performed simultaneously with these two methods to present a comparison of Manning’s roughness coefficient. Based on the comparison of the result, it is well found that both the Acoustic Doppler current profilers (ADCP) Method and the current meter method were found to return similar results, although the data obtained using the ADCP has demonstrated greater versatility and acceptability as a method to more precisely estimate the Manning's roughness coefficient. This approach enhances the accuracy of forecasting water flow in channel networks, making it more efficient. This experimental study shows that Manning’s roughness coefficient can also be obtained by the ADCP Technique which is simple, rapid, and efficient.