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Tracking Geomorphic Signatures of Watershed Suburbanization with Multi-Temporal LiDAR
Citation:
Jones, D., M. Baker, A. Miller, T. Jarnagin, AND D. Hogan. Tracking Geomorphic Signatures of Watershed Suburbanization with Multi-Temporal LiDAR. Geomorphology. Elsevier BV, AMSTERDAM, Netherlands, 219(0):42-52, (2014).
Impact/Purpose:
Sequential LiDAR acquisitions used to study watershed geomorphic changes over time due to urbanization• Sequential LiDAR DEMs used to track geomorphic changes during urbanization process.
Description:
Urban development practices redistribute surface materials through filling, grading and terracing, causing drastic changes to the geomorphic organization of the landscape. Many studies document the hydrologic, biologic, or geomorphic consequences of urbanization using space-for-time comparisons of disparate urban and rural landscapes. However, no studies document watershed-wide geomorphic changes as they occur throughout development, largely due to insufficient data availability. We utilized a time series of five sequential Light Detection and Ranging (LiDAR) derived digital elevation models (DEMs) to track watershed geomorphic changes throughout development (2002-2008) across multiple spatial scales (0.01-1 km2). Development-induced changes were compared against an undeveloped forested watershed throughout the same time period. First, elevation variation was summarized as standard deviations calculated through time and averaged across space. Second, pre and post development slope distributions were compared in profile and as standard deviations calculated using a moving window to highlight urban topographic modifications. Third, hypsometric curves generated for each DEM year were used to track aggregate hillslope profile changes summarized at multiple spatial scales (0.01-1 km2). Finally, pre and post development surface drainage network structures were compared to document channel burial and engineered surface conduit additions. Our work highlights important considerations for temporal DEM-based analysis previously unreported in the literature. Novel methods introduced here may allow improved understanding and targeted mitigation of the processes driving geomorphic changes during development and help guide future research directions for development-based watershed studies.