Design examples 6. Designexamples 6.1 Chapter 6. Design examples 6.1: permeable pavement (level 1) and sheet Flow to Conservation area The site plan and drainage area map for Example 1 is shown in Figure 6.1.1. The site is a small commercial facility that hosts receptions and social events and therefore has a large number of parking spaces. The site consists of 5.6 acres of open space, managed.