Impacts of Flooding on Wastewater Infrastructure: Tradeoffs of Recovery and Resilience

As climate change persists, the frequency and intensity of natural disasters has increased, emphasizing the need for resilient critical infrastructure. This study analyzes sustainability impacts of resilient and recovery infrastructure for water resource recovery facilities (WRRFs) affected by flooding, considering potential operational and structural failures. A detailed inventory was collected for 10 reflective case studies to analyze life cycle environmental impacts of initial construction, recovery construction following a natural hazard, and resilience infrastructure that can help prepare for future natural hazards. Economic and additional impacts of flooding were evaluated using generalized WRRF cost models and anecdotes from relevant stakeholders, respectively. Generally, initial construction has a higher environmental and economic impact compared to recovery and resilience construction. Recovery construction tends to have higher environmental and economic impacts compared to resilience construction when major equipment replacements and repairs are necessary. Conversely, resilience construction tends to have higher environmental and economic impacts compared to recovery infrastructure when major construction activities and resources are required. If multiple flooding events occur during a facility's design life, recovery construction impacts increase based on the number of flood events and can become larger compared to initial and resilience construction impacts, highlighting the uncertainty associated with recovery needs compared to the stability of resilience. Additional impacts of flood recovery were identified and discussed, including treatment, workers, community life, and facility impacts, which were often driving factors considered by decision-makers if resilient infrastructure was or will be implemented. This study aims to provide justification for communities, engineers, and funding agencies as they seek to protect critical wastewater infrastructure via resilient investments.