A single rainfall event can contribute the majority of runoff for the entire growing season. These events are episodic and region specific. That's why Discovery Farms Minnesota uses automated equipment that collects samples whenever water is flowing. This time lapse video shows a runoff event that occurred over 16 hours on June 15, 2011. This storm delivered 3.76 inches of precipitation, which was preceded by a 1.3 inch rain the day before.