Collaborative Research: P2C2: Extreme floods on the lower Mississippi River in the context of late Holocene climatic variability

Northeastern University, Boston MA

Investigators

Abstract

The Mississippi River plays a fundamental role in the economy of the United States, and flooding along its course is costly in both economic and social terms. Historic flooding of the lower Mississippi in 2011 caused over $3 billion in agricultural losses and damage to infrastructure, with additional losses to flooding occurring again in 2016 and 2018. Seasonal and longer-term predictions of flooding along the Mississippi and its major tributaries remain a major challenge because the effects of climate variability, greenhouse forcing, and human modifications of the river are difficult to disentangle using short records from gauging stations that span less than 150 years. This project will develop records describing the timing and magnitude of flooding across the Mississippi River basin over the last millennium, and use these records to understand the influence of climate variability on flood activity. This work will improve predictions of flooding along the Mississippi River, a hazard that affects millions of people. The findings will be useful for planned and ongoing efforts to slow coastal land loss in the Mississippi River delta. The project will engage students at three institutions in research, and its findings will be disseminated to the public through an exhibit at the Mississippi River Museum and Aquarium. The goal of this project is to reconstruct the frequency and magnitude of overbank floods along the lower Mississippi River and its major tributaries over the last millennium using the sedimentary archives preserved in oxbow lakes. Our ability to create this novel hydrological record is due to recent developments in paleoflood hydrology that demonstrate the unique ability of floodplain lake sediments to record individual flood events and their associated magnitude. Once developed, our reconstructions will be used to characterize decadal- to centennial-scale variability of flood activity, to compare with simulated discharge extremes in climate model ensembles, and to identify the regional and hemispheric circulation patterns associated with increased likelihoods of extreme floods on the lower Mississippi River and its major tributaries. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.