Productive Blue-Green Roofs for Stormwater Management

Abstract

Green roofs have been used around the world for centuries, and have been adapted to modern urban buildings. Many cities have now adopted a green roof bylaw in recognition of their environmental benefits, including stormwater management. Despite this requirement, if green roofs are poorly designed, they may quickly become ineffective or counterproductive. In this paper, features of green roofs that are important for sustained environmental benefit are highlighted with a focus on water demand and management. Blue roofs use specialized retention layers to delay stormwater run-off or retain it for evaporation. Blue and green roofs can be combined to grow productive, or edible crops and this use can have synergistic benefits. This paper describes case studies and testbeds of various combinations of green and blue roof sublayers with edible and non-edible plants. Design parameters are considered and monitoring and automation systems are described.