Stu Ostro posted an amazing video of water runoff resulting from the tremendous rains spawned by Typhoon Morakot in ChiaYi, Taiwan. Here is a radar loop of the storm that he also linked.
The person who posted the video said the storm produced "over a meter of rain on my location, with over 2m in the mountains (and counting!). The dam on the south side of the city is overtopped and incredibly violent. A massive hydraulic jump is visible."