The effects of current landscape configuration on streamflow within selected small watersheds of the Atlanta metropolitan region

Study region: This study investigated impacts of current landscape configuration on stream flow within selected small watersheds of the Atlanta, Georgia metropolitan region (AMR). Study focus: To determine effects of current landscape arrangement on watershed-wide Hydrologic Unit Code (HUC)-12 land cover/land use (LC/LU), the configurational metric of contagion was chosen. Contagion-adjusted curve numbers (CNs) were calculated for all 405 HUC-12 watersheds in the AMR. 6 watersheds were chosen for Thornthwaite Water Balance (TWB) model evaluation based upon having a stream gage record of the 5 year (60 month) period most closely associated with contagion and CN values derived from the 2011 National Land Cover Dataset (NLCD). 4 watersheds out-performed their original CN watershed simulations based upon: Nash-Sutcliffe efficiency (NSE); room mean square error (RMSE)-standard deviation ratio (RSR); and Akaike Information Criteria (AIC) analysis. New hydrological insights: Configurational metrics related to contagion of the aggregation index (AI) and dumpiness index (CI) indicated possible reasoning to explain differences found between the 4-watershed and 2-watershed categories. The Al of agricultural LC/LU within the 2-watershed category suggested greater landscape heterogeneity due to agricultural patch disaggregation, whereas the CI suggested greater overall disaggregation and landscape dispersion for all non-water LC/LU patches within the 2-watershed category and pointed towards greater landscape heterogeneity driven by higher dispersal of non-water patches. Both may lead to complex flow patterns not easily estimated within streamflow simulations. (C) 2015 The Author. Published by Elsevier B.V.