Gone but not forgotten: The impact of buried streams and wetlands on flood risk in urbanized landscapes

Keywords: Flood risk, buried streams, urbanization, Geographic Information Systems (GIS), Detroit MI
Abstract Type: Poster Abstract

Abstract

A changing climate is impacting flood risk in the United States, as flood events become more intense and frequent. In urban environments, buried streams and wetlands, which tend to retain an identifiable topographic depression in the landscape, may increase flood risk for contiguous parcels and buildings. This study uses spatial and statistical analysis to correlate the location of buried streams and wetlands with a proprietary flood risk dataset (First Street Foundation’s “Flood Factor”) in Metro Detroit, Michigan (USA). We extracted a high-resolution stream network for the Rouge River Watershed from a Light Detection and Ranging (LiDAR) elevation dataset and identified buried streams and wetlands where indicative topography (low-lying dendritic patterns or other low-lying areas) was decoupled with extant streams in satellite imagery. We then correlated nearby properties’ proximity to buried streams and wetlands with their Flood Factor, an aggregate flood risk metric which assigns a value between 1 and 10 (minimal to extreme risk) We weighted based on stream order or total area (as proxies for natural water volume) for buried streams and wetlands, respectively, as larger buried streams/wetlands were expected to have a greater influence on flood factor. The analysis revealed an irregular influence of proximity to buried streams and wetlands on a parcel’s flood factor, with some areas showing a stronger influence than others. This study begins to unravel the relationship between stream burial and property-based flood risk, an increasingly important subject for property owners and municipalities globally.