Impact of urbanization on baseflow characteristics in the central catchment of North China Plain, China

Study area The Dawenhe River and Xiaoqinghe River Basins (116 degrees 21 '-118 degrees 41 ' E, 35 degrees 43 '-37 degrees 15 ' N) in the center of the North China Plain (NCP), China. Study focus To quantitatively assess the influence of urbanization (two indicators including Impervious Surface Percentage (ISP) and Average Night Light Index (ANLI)) on baseflow hydrological behavior (nine baseflow signatures), this study selects the typical urbanized catchment (nine sub-catchments) within the central NCP, where the baseflow was estimated from the total daily streamflow from 2006 to 2016. New hydrological insights for the region Findings show that: (i) Baseflow signatures had a notable spatial variability, in which the magnitude baseflow signatures (Q(b10), Q(b25), Q(b50), Q(b90)), Baseflow Index (BFI), Concavity Index (CI), and Slope of the baseflow duration curve (S-BDC) demonstrated greater values in the north versus the south. (ii) Both ISP and ANLI exhibited an upward trend over time with some fluctuations (R-2 > 0.65, p < 0.05). For ANLI, there were higher values in the northwest and northeast regions, and the higher ISP values were mainly located in the northern region. (iii) Overall, the effects of two urbanization indicators on baseflow signatures exhibited catchment-variability, and model performance between ISP and baseflow signatures is better than ANLI. This study provides a scientific reference to elucidate the water balance of the central NCP under the background of urbanization.