Performance of Urban Rainwater Retention by Green Roof: A Case Study of Jinan

Abstract

Green roof can significantly reduce runoff volume and delay the duration of rainwater compared to a conventional roof; however there is insufficient research in China regarding rainwater retention performance. In this research, a comparison of a green roof with a conventional roof on rainwater retention is quantified. Results suggest that the specified sedum green roof delays the start and end time of runoff for 3 –13 and 4 –8 minutes. Artificial rainfall runoff retention ranged from 52.86% to 71% for the green roof. On the retention efficiency, potential 3141.77 ×104m3rainwater could be retained by urban green roof in Jinan. The green roof is demonstrated an optional measure to reduce the quantity of rainwater entering already overburdened city drainage systems with great huge economic and environmental benefits.