In this chapter, each of the following sections addresses the engineering and
landscape architectural purviews for the design of individual elements of exten-
sive living roofs. The issues addressed highlight crucial requirements for stormwa-
ter control and its potential influence on architecture, and vice versa. Extensive
living roofs influence the runoff hydrograph in multiple ways, but the main
effects are retaining rainfall within the growing medium and detaining (slowing)
runoff release rate.