John Wiley & Sons Ltd and The Chartered Institution of Water and Environmental Management (CIWEM) 約翰威立出版有限公司與英國皇家特許水與環境管理學會
Increases in impervious surfaces and land-use changes associated with urbanization have long been the focus of urban hydrological research. However, studies and calculations that consider impervious surfaces alone do not encompass
all factors that influence urban hydrologic response, as alternative urban structures may have a substantial effect on stormflow. This study examines several
descriptors to improve estimations of hydrologic impacts of urbanization in
small watersheds. Configurations of drainage densities that include storm
sewers were computed for the highly urbanized Rocky Branch Watershed.
Storm sewer configurations resulted in an approximate tripling of the drainage
density. In addition, rainfall and stormflow data were analyzed to compare the
hydrologic response of two subcatchments with varying percentages of impervious areas and drainage densities. The subcatchment with a higher percentage of impervious area produced significantly (p < .01) higher runoff volumes
with an average runoff coefficient of 0.446, while the subcatchment with
higher storm sewer densities displayed significantly shorter lag times of 9 min.
In this case, the percentage of impervious area increased the volume of runoff
but, storm sewer densities accelerated hydrologic responses, suggesting that
hydrologically relevant metrics should be considered to accurate assess flood