The Influence of Urban Development Patterns on Streamflow Characteristics in the Charlanta Megaregion

Although it is widely recognized that urbanization has a notable impact on streamflow characteristics, the relative influence of the extent, spatial configuration, and positioning of urban development on low, high, and peak flow regimes is still not fully understood. The overarching research objective of this study was to clarify these relationships by analyzing 119 watersheds throughout the Charlanta megaregion, which stretches from Charlotte, NC to Atlanta, GA. Spatial metrics were derived from land use/land cover data sets to quantify the urban development patterns of each watershed while the streamflow characteristics were evaluated using mean daily discharge and annual peak streamflow data. Analysis of variance tests, bivariate correlations, and multivariate regression models were used to identify intraregional variability and quantify the impact of urban development patterns on streamflow characteristics while controlling for the physical differences between watersheds. The statistical analysis revealed that increasing the extent of urban development enhanced high and low flow frequency as well as annual peak unit discharge. Therefore, urbanization within Charlanta generally produced a more extreme streamflow regime. In terms of the spatial configuration of urban development, the models indicated that more contiguous developed open space increased high and low flow frequency. Finally, the positional analysis suggested that clustering impervious surfaces in source areas distant from streams increased the frequency of high flows. The study highlights the overall importance of considering the extent, configuration, and positioning of urban development when devising land use policies aimed at minimizing streamflow alteration due to urbanization.