Ricerc@Sapienza

Skillful predictions of the frequency of flood events over long lead times (e.g., from one to ten years ahead) are essential for governments and institutions making near-term flood risk plans. However, little is known about current flood prediction capabilities over annual to decadal time scales. Here we address this knowledge gap at 286 U.S. Geological Survey gaging stations across the U.S. Midwest using precipitation and temperature decadal predictions from the Coupled Model Intercomparison Project (CMIP) phase 5 models.

There is growing empirical evidence that many river basins across the U.S. Midwest have been experiencing an increase in the frequency of flood events over the most recent decades. Albeit these detected changes are important to understand what happened in our recent past, they cannot be directly extrapolated to obtain information about possible future changes in the frequency of flood events. Building on recent statistically-based attribution studies, we project seasonal changes in the frequency of flood events at 286 U.S. Geological Survey gauging stations across the U.S.

The frequency of flood events has increased across most of the U.S. Midwest in the past 50–70 years; however, little is known about what is driving these changes. Using an observation-driven approach, we develop a statistical framework to attribute the changes in the frequency of flood peak events to changes in the climate system and to land use / land cover. We focus on 287 U.S. Geological Survey sites with at least 50 years of daily discharge measurements between the second half of the 20th century and the present.