Peak Flow Event Durations in the Mississippi River Basin, and Implications for Temporal Sampling Requirements to Capture River Dynamics

Peak flow events and their inherent time scales in rivers are a key aspect of flood studies in hydrology. Yet it is still unclear how often should a river be observed to accurately determine the magnitude and duration of extreme events. This work aims to quantify peak flow event durations and their impact on river sampling requirements. The analysis is performed over the Mississippi basin using hourly gages over 2010-2022. Selected streamflow statistics all lie within a 2.5% error range for sampling periods up to 8 days. Median event duration ranges from around 2 to 30 days with great upstream-downstream spatial contrast. A minimum temporal sampling 4x (2x) faster than peak flow event median duration is required to detect 95±3% (85±5%) of events and to estimate their duration with a 90±5% (75±10%) median accuracy. Our findings have direct implications for future satellite missions concerned with capturing flood events.