Description

1) Planning for the Future: Probabilistic Pluvial Flooding Predictions
Susan Marlow, GISP, Stantec, susan.marlow@stantec.com
Co-presenters: None

Abstract: Tennessee has experienced extreme weather events at an increasing frequency that have caused severe flooding, destruction, and the tragic loss of lives. Using funding from the U.S. Department of Housing and Urban Development (HUD) Community Development Block Grant - National Disaster Resilience Competition (CDBG-NDR), the Tennessee Economic and Community Development Department (TNECD) partnered with Stantec, to integrate a new decision-support technology to strengthen its resiliency efforts against flooding. Flood Predictor, a proprietary product developed by Stantec, is a machine learning flood-risk technology based on FEMA Risk MAP data that provides Tennessee communities high-quality pluvial flood predictions to support disaster planning, response, and mitigation. TNECD has integrated Flood Predictor results into TNPlan web portal—an online repository of resilience data that gives government leaders, community officials, and emergency managers quick and efficient access to insights to flood risk when future disasters strike. This presentation will detail the methodology used to create probabilistic pluvial flood predictions, the TN Plan web portal, and how Tennessee is using these predictions to better prepare for and respond to rainfall events and ultimately save lives.

2) Implementation of Forecast Flood Inundation Mapping for the Nation
Mark Glaudemans, PE, National Weather Service, mark.glaudemans@noaa.gov
Co-presenters: David Vallee, NOAA/NWS Office of Water Prediction/National Water Center, David.Vallee@noaa.gov

Abstract: The NOAA National Weather Service (NWS) has a mission to issue forecasts for the protection of lives and property, the delivery of impact-based decision support services, and the enhancement of the national economy. Partners across the nation have expressed an urgent need for more detailed flood forecasts and the resulting inundation information. There is a demand for event-driven flood inundation mapping (FIM) as a high value source of actionable information for emergency and water resource managers to prepare, mitigate, and respond to flood impacts. In response, the NWS National Water Center, in coordination with River Forecast Centers (RFC) and Weather Forecast Offices (WFO) and Federal and other partners, has developed high-resolution inundation modeling capabilities providing geo-referenced visualizations of forecast flooding extent at the continental scale. The NWS FIM methods deploy a model agnostic approach to map the inundation at a 10-meter horizontal resolution for rivers and streams in the National Hydrography Dataset network. Synthetic rating curves and the application of the Height Above Nearest Drainage method allow projection of the water surface elevation in the channel to neighboring cells in the digital elevation model. Through two Department of Commerce Agency Priority Goals, NOAA has demonstrated the FIM capability for over 20 million Texas residents and 95 million residents in the Northeast U.S. Over the next 4 years, NOAA will revolutionize water prediction capabilities by providing event-driven high spatial resolution forecast FIM for nearly 100% of the U.S. population. This presentation will highlight these demonstrations and the initial rollout of services to 10% of the nation by September 2023 for areas in the Northeast and Texas. These FIM services include the hourly updated analysis and 5 day forecast FIM driven by the official NWS River Center Forecasts and by the National Water Model guidance.

3) Innovations in flood hazard mapping: Adaptation to a changing climate and an eye toward equity
Haley Selsor, student, University of Georgia, hks47033@uga.edu
Co-presenters: Matt Chambers; Scott Pippin

Abstract: Urban flooding is a growing threat due to land use and climate change. Flood risk is typically measured by physical impacts or damages in the form of a monetary value. However, floods can cause long-lasting, devastating consequences born by socially vulnerable communities that impede recovery as a result of historical societal and institutional influences. As urban populations are increasing alongside the threat of urban flooding, there is a need to incorporate the social implications of flooding when evaluating flood risk. In a case-study of Athens-Clarke County, we investigated the distribution of flood exposure and identified communities who are overexposed to flooding. We found that socially vulnerable communities have disproportionately greater flood exposure, reflecting similar patterns across the Southeastern United States. This work also investigates the variation in equitable exposure across flood magnitudes, and we found that the largest inequities occurred for the smaller events instead of the 100-year flood event. In order to do this analysis, we integrated the physical and social impacts of flooding into a single metric to quantify flood risk equity. In this presentation, we will demonstrate how this metric can be used to evaluate the social implications of engineering interventions to aid in the decision-making process.