Effect of meteorological conditions on onsite runoff control for reducing the hydrological footprint of green building

Abstract

Rainwater management is an essential part of sustainable site of a green building, in which the complexity of meteorological conditions is a difficult problem to deal with. In this study, based on 20 year's daily historical records, five cities were selected to represent rainfall disparity between 50 state capitals of the United States of America. Then, the sites' hydrologic responses to different rainfall conditions were simulated over 30 year's hourly historical records, and the statistics of rainfall/runoff events were plotted into hydrological frequency curves to represent the site hydrology. The difference between different scenarios is reflected by comparing water balance and hydrological frequency curves. The results showed that average daily rainfall depth and average annual rainy days are two conditions with greatest effects on runoff potential. Retaining the 95–99th percentile rainfall event is required as design objectives for three sites to replicate predevelopment runoff characteristics, while even the 99th percentile was not enough for the other two sites, unless impervious cover reduced or the design storm doubled. Onsite runoff control minimized the impact of site development on runoff, but not on infiltration and evaporation. The sites evaporation increased from 1% to 11–36%. Besides, The distance between the obtained runoff frequency curve and the designed counterpart suggested that rainfall retained in situ was less than the design objective because of precipitation concentration, which is worthy of consideration in future research to reduce hydrological footprint of green building more economically and effectively.