Question 184Navigation General

The correct answer is C) 57.4 feet. To arrive at this answer, we need to understand the relationship between the upper pool elevation, the gage reading, and the vertical clearance at the bridge. The normal upper pool elevation is 420.0 feet MSL, which corresponds to a gage reading of 12.0 feet. When the gage reads 27.2 feet, the pool elevation has increased by 15.2 feet (27.2 - 12.0). Since the vertical clearance at the bridge is 72.6 feet above the normal pool, the new clearance with the increased pool elevation is 72.6 - 15.2 = 57.4 feet. The other options are incorrect because they do not properly account for the change in pool elevation based on the gage reading.