What does a storm hyetograph measure?

A storm hyetograph is specifically designed to represent rainfall intensity over time during a storm event. It displays how the rate of rainfall changes, indicating variations in intensity throughout the storm's duration. Therefore, the correct interpretation of a storm hyetograph involves capturing instantaneous rainfall intensity as a function of time, which allows engineers and hydrologists to analyze and understand how rainfall varies during the event.

While total rainfall amount over a given period captures cumulative rainfall, it does not provide insight into the rate of that rainfall throughout the storm. Likewise, average rainfall for a particular season does not reflect the variability and dynamics of rainfall intensity characteristic of a specific storm. Rainfall distribution over storm duration could implicate total rainfall but lacks the temporal specificity that defines instantaneous rates, which is critical for understanding peak flows, runoff, and the design of drainage systems. Thus, the measurement of instantaneous intensity as depicted in the storm hyetograph is a crucial factor for effective hydrological modeling and stormwater management.