Task: Question Generation
Input (English): Background Paragraph: The water level is seasonal, being lowered by about 10 feet (3.0 m) over the winter. The reservoir fills in the spring from snow melt and underground springs. The lake is usually at full level by late spring, but in the occasional years of low snow melt and low rainfall, it may remain up to several feet below its typical level. Water is let out of the lake in the fall so that ice will not damage docks and other structures around the lake. This also leads to excellent water quality, as a significant portion of the water is replaced every year. 
Story: The water level in Large Lake was high in March, 3 feet higher in April, and 7 feet higher still in May. It dropped to a much lower level in September, October and November, when they released a significant portion of the water as a yearly chore.
Output (English): When was the water level lower, in April or in September?