A project is proposed on a 1200sm lot area. Currently, the lot consists of flat vegetation surface with an existing imperviousness of less than 50%. The proposed design is to meet LEED SS Credit 6.1 - Rate and Quantity - Option 1. In your first design submission of 2 storey building , which consists of 690 sm of conventional roof and 120sm of concrete and asphalt paving area was rejected as the total imperviousness area exceeded 50%. Which of the following design solution improves the site imperviousness to less than 50%? Design 1: Change 20% of the Conventional Roof area to Garden Roof (<10cm) surface type and 50% of the concrete pavement area to Gravel. Design 2: Change the entire concrete pavement area (120sm) to Gravel and keep the building roof as conventional. Design 3: Propose 50% of the Roof area as Garden Roof (<10cm) and keep the pavement area as concrete. Refer Runoff Coefficient below