Environmental damage associated with severe hydrologic events: a LiDAR-based geospatial modeling approach

Increasingly, extreme hydrologic events are causing flooding and infrastructure damages in excess of one billion dollars per event. Hurricane storm surge is most frequently implicated; however, rainfall dominated events may have more damaging and costly impacts. Additionally, the environmental impacts and consequences of such events are not often considered in estimates of flood damage or in mitigation efforts. This paper integrates geographic information systems, floodplain analysis, observed flood level data, and public sources of pollutant releases to describe the environmental impacts of severe hydrologic events and identify infrastructure vulnerabilities with an emphasis on environmental facilities. Observed high water marks from recent significant flooding events, coupled with LiDAR data, were used to create high-resolution inundation maps. The degree of inundation of facilities with the potential to cause environmental impacts, such as wastewater treatment facilities, landfills, and Superfund sites, was modeled. The results indicated that rainfall-based flooding events could cause substantially more inundation of environmental facilities compared to surge-based flooding. Additionally, 100 and 500-year floodplain mapping was not sufficient to identify facilities at risk of inundation or spillage. The results from the study enable the determination of locations and facilities that are highly susceptible to environmental pollution due to flooding that would be candidates for increased resilience planning.