Beyond Impervious: Urban Land-Cover Pattern Variation and Implications for Watershed Management.
Impervious surfaces degrade urban water quality, but their over-coverage has not explained the persistent water quality variation observed among catchments with similar rates of imperviousness. Land-cover patterns likely explain much of this variation, although little is known about how they vary among watersheds. Our goal was to analyze a series of urban catchments within a range of impervious cover to evaluate how land-cover varies among them. We then highlight examples from the literature to explore the potential effects of land-cover pattern variability for urban watershed management. High-resolution (1 m(2)) land-cover data were used to quantify 23 land-cover pattern and stormwater infrastructure metrics within 32 catchments across the Triangle Region of North Carolina. These metrics were used to analyze variability in land-cover patterns among the study catchments. We used hierarchical clustering to organize the catchments into four groups, each with a distinct landscape pattern. Among these groups, the connectivity of combined land-cover patches accounted for 40 %, and the size and shape of lawns and buildings accounted for 20 %, of the overall variation in land-cover patterns among catchments. Storm water infrastructure metrics accounted for 8 % of the remaining variation. Our analysis demonstrates that land-cover patterns do vary among urban catchments, and that trees and grass (lawns) are divergent cover types in urban systems. The complex interactions among land-covers have several direct implications for the ongoing management of urban watersheds.
Department of Forestry and Environmental Resources, College of Natural Resources, North Carolina State University, Campus Box 8008, 2820 Faucette Blvd, 4120 Jordan Hall, Raleigh, NC, 27607, USA. smbeck@ncsu.edu.
Scott M
SM
Beck
Department of Forestry and Environmental Resources, College of Natural Resources, North Carolina State University, Campus Box 8008, 2820 Faucette Blvd, 4120 Jordan Hall, Raleigh, NC, 27607, USA.
Melissa R
MR
McHale
Department of Forestry and Environmental Resources, College of Natural Resources, North Carolina State University, Campus Box 8008, 2820 Faucette Blvd, 4120 Jordan Hall, Raleigh, NC, 27607, USA.
George R
GR
Hess
D003247:Conservation of Natural Resources / Q000379:methods*; D009657:North Carolina; D006109:Poaceae / Q000254:growth & development; D014197:Trees / Q000254:growth & development; D014507:Urbanization / Q000639:trends*; D060753:Water Quality; D062066:Water Resources / Q000600:supply & distribution*
GIS; Remote sensing; Urban ecology; Water quality