Calculate the corresponding hydraulic mean depth that would exist in the channel if the bed was unrippled. The rugosity coefficient in an unrippled channel is 0.015 and the rugosity coefficient actually observed by experiments on the rippled bed of channel is 0.020. Consider the value of hydraulic mean depth of the channel as 1.5 m.

• A. 1.5 m
• B. 2.5 m
• C. 0.97 m
• D. 0.77 m