The pilot was practicing landings. After the last “smooth” landing, the airplane veered right. The pilot corrected with left rudder and the airplane initially corrected left; however, it then veered “sharply” right against the application of full left brake and rudder. The airplane departed the right side of the runway and came to rest upright in a creek. During the runway excursion, the left wingtip struck the water and ground. The airline transport pilot and passenger were not injured. Visual conditions prevailed.
