A Stormwater Pipe in is a fixed structure used to direct stormwater runoff away from populated areas. There are two sub-types Pipes and Culverts whose shape can be either box or Circular. Culverts are structures that direct water from one side of a road to another and are not connected to a network system (Span, height or diameter is less than 1.8 metres, cross - sectional area of each cell is less than 3 square metres and Which may sit on a concrete base). Whilst they are usually headwall to headwall, they may be pit to headwall.