Hurricane Ida in New York Technical Report 1: Building Performance: Basement Buildings and Urban Flooding

This technical report examines the performance of buildings with basements during the urban flooding caused by Hurricane Ida in New York City. It analyzes how surface water and sewer backup led to basement flooding, assesses structural damage, and reviews the effectiveness of dry floodproofing and other mitigation measures. The report provides recommendations for building owners, city officials, and design professionals to improve occupant safety and building resilience, including the use of water sensors, reinforcement of basement walls, and safe pumping practices. Lessons from prior urban flood events are also discussed to inform future mitigation strategies.