Use of LiDAR data in defining the urban-rural transition zone in stream cross-section morphology.

摘要

Stream channel geometries have been found to enlarge with urbanization of the upland drainage basin. Although enlargement has been documented in a variety of climatic and urban regimes, little is known about how the geomorphic effects of urbanization translate into rural areas downstream. Models derived from Light Detection and Ranging (LiDAR) data from the North Carolina Floodplain Mapping Program were used in conjunction with field surveys to explore the urban-rural transition for North Buffalo Creek in Greensboro, NC. Although the model did not accurately represent at-a-point channel geometries, it was able to represent the prevailing geometric relationships between contributing drainage area and averaged channel capacity for channel reaches of approximately 140m. The urban-rural transition for North Buffalo Creek was found to be linear, with decreases in enlargement beginning well within the current urban boundary. Using linear regression, a truly "rural" state was predicted to be achieved when the channel reaches a contributing drainage area of between 400--450km2. Local increases in enlargement were found to be directly influenced by the junction of major tributaries.