Golf: Provisional Ball Hit into Water Hazard - Player Options

Question
We were playing a course we were unfamiliar with my opponet hit a ball that went into the rough and he was afraid that it may be lost so he hit a Provisional Ball. When we got to where we thought his ball would be, we discovered that he had hit it into a water hazard that we could not see from the Tee Box. What are his options?

Answer
Scott,

Since your opponent hit the provisional ball under the impression that the ball was lost outside a water hazard, he must abandon the provisional ball and proceed under Rule 26-1 (Relief for ball in water hazard).

Thanks for the question,

Michael Hoffman