To calculate the distance, we can use the equation that describes the relationship between distance, acceleration due to gravity, and time.

$$d = (1/2) * a * t^2$$

where d is the distance, a is the acceleration due to gravity (approximately 9.8 m/s^2), and t is time.

In this case, we know that the rock took 3 seconds to travel the distance and splash into the water. So plugging in t=3s into the equation:

$$d = (1/2) * 9.8 m/s^2 * (3s)^2$$

$$d = 14.7 \ m$$

Therefore, the distance to the water surface is 14.7 meters.