The months that show the greatest runoff are not necessarily the same months that have the highest precipitation. The infiltration/runoff ratio in a region is influenced by several factors, such as frozen or saturated soil and spring snowmelt. The type of soil will also influence it as will vegetation (and corresponding evapotranspiration).

I would assume that the large stream flow value (1,120 cu ft/sec) in April--which was not associated with a significant precipitation event--was probably due to melting snow and ice combined with saturated soil. Conversely, the June increase in stream flow corresponded to 4 inches of precipitation! December also had a peak stream flow event. At this time of the year the ground was likely frozen and could not absorb additional precipitation. In addition, the precipitation that occurred in December was probably frozen, and did not contribute to melt related runoff for a period of time.

This type of data would easily fit into Connecticut science framework, content standard 9.7 - Elements on Earth move among reservoirs in the solid earth, oceans, atmosphere and organisms as part of biogeochemical cycles, expected performance D 20: "Explain how solar energy causes water to cycle through the major earth reservoirs."

There are many types of data that could be imported into excel and applied to the curriculum. For example, data about atmospheric gas concentration, data corresponding to heat flux values, data related to energy resources & energy consumption, etc. are examples that come to mind.