An integrated modeling approach to evaluate the impacts of nature-based solutions of flood mitigation across a small watershed in the southeast United States

Abstract. Floods are among the most destructive natural hazards in world, posing numerous risks to societies and economies globally. Accurately understanding modeling floods driven by extreme rainfall events has long been a challenging task domains of hydrologic science engineering. Unusual catchment responses flooding cause great difficulty predicting variability magnitude floods, as well proposing solutions manage large volumes overland flow. The usage nature-based (NBSs) proved be effective mitigation flood peak rate volume urban or coastal areas, yet it is still not widely implemented due limited knowledge testing compared traditional engineering solutions. This research examined an integrated hydrological hydraulic system understand response at-risk watershed evaluate efficacy NBS measures. Using Hydrologic Engineering Center Modeling System River Analysis (HEC-HMS HEC-RAS) software, hydrologic–hydraulic model was developed for Hurricane Matthew- (2016) Florence-driven (2018) across Little Pee Dee–Lumber watershed, North South Carolina (the Carolinas), US. focus on Nichols, small town that disproportionately impacted during these two hurricane events. present article proposes methodology selecting, modeling, evaluating performance measures within catchment, which can extended other case studies. Different measures, including storage ponds, riparian reforestation, afforestation croplands, were designed, modeled, evaluated. Matthew's event used scenarios given its high simulation accuracy inundation less accurate results obtained Florence. scenario comparison evidenced large-scale interventions, such reduce inundated area Nichols 8 % 18 %. On contrary, smaller-scale interventions reforestation ponds showed negligible effect only 1 mitigation.