Kentucky and adjacent Appalachian regions suffer repeated tragic loss of life and property damage due to flash flooding. Flash floods in eastern Kentucky are unique with respect to the frequency, magnitude, duration, and timing of stormwater delivery. However, the mechanisms controlling flash flood generation are poorly understood in this region. The proposed project will inform understanding of flash floods in eastern Kentucky and throughout Appalachia. The data from this study will assist with understanding the watershed properties that control the generation of flash floods and will assist with post-flood analyses to determine the mechanisms of the July 2022 floods in eastern Kentucky. These data will additionally improve flash flood forecasting technology, which may assist with the mitigation of the impacts of future flash floods.<br/><br/>Flash floods – defined as the swift increase in discharge caused by intense rainfall or release of water over a small region – rank as the most destructive weather-related hazard in many locations of the world. The July 2022 flash flooding in Eastern Kentucky resulted in at least 37 deaths, including 4 children, with hundreds of homes destroyed. Flash flooding is not a new phenomenon to this region. However, the July 2022 floods resulted in one of the largest number of fatalities due to flash flooding in the US in over 45 years, placing it as one of the deadliest flash floods on record. The objectives of this project are to: 1) investigate the downstream impacts and behavior of flash floods in headwater streams by gathering critical and timely data that will lead to improved prediction and modeling of flash flood dynamics; and 2) understand the continued impact of flash floods on water quality in headwater streams throughout Appalachia. Three main research tasks will be performed to accomplish the research goal: 1) collect perishable high-water mark data, 2) collect soil samples to quantify soil-water condition and perform soil characteristic tests to assist with hydraulic model calibration for future projects, and 3) analyze surface water and sediment samples for stormwater indicators. Data collected through this research will eventually be used to create hydraulic models to understand velocities and volumes of water produced at the headwater-scale and answer questions related to the contribution of headwaters to downstream flash floods.<br/><br/>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.