You Are Doing a Hydrographic Survey by the Sand Heads

Multiple Choice

You are doing a hydrographic survey by the Sand Heads Light, off the mouth of the Fraser River in very silty green water.You lower a bar to check its reflection and calibrate your sounder.You find that the fresh river water has dropped the speed of sound to 1483 m/sec.If the bottom registers at 15 milliseconds (0.015 sec) , how deep is the top of the Fraser delta? Use the equation: depth (m) = 0.5 * (1500 m/s * total 2-way travel time in sec)

A) 11.12 metres
B) 11.25 metres
C) 22.25 metres
D) 2250 metres