The present work provides a new methodology for the flow measurement in a lined canal Huma tail distributary of Hirakud canal system, Odisha, India.The acoustic Doppler velocity meter was used for the direct measurement of velocity over full area and the length of canal. The entropy based Chiu's equation is used in the present work to find out a constant ratio between the average and the peak velocity of the channel. The location for maximum value is found from the velocity profile. Applying the constant ratio, the mean velocity can be obtained at various sections. With the measured cross sectional area and the mean velocity the discharge can be found. The maximum velocity is a technically important parameter always consists of a single value regardless of the flow conditions, and a cross-sectional shape. Thus the maximum velocity can be applied to estimate the mean velocity. In this work a formula based on the entropy concept has been used to find out the maximum velocity. The accuracy was verified using 13 sets measured with the help of ADV flow tracker. A comparison of the velocity estimated with the value actually measured showed very high accuracy.