![]() ![]() Clogging progressively reduces the pavement's permeability in direct proportion to the cumulative volume of runoff treated. Number of pavement layer void volumes of runoff treated it takes to completely clog the pavement. The permeability of new porous concrete or asphalt is very high (e.g., hundreds of in/hr) but can drop off over time due to clogging by fine particulates in the runoff (see below). Permeability of the concrete or asphalt used in continuous systems or hydraulic conductivity of the fill material (gravel or sand) used in modular systems (in/hr or mm/hr). Ratio of impervious paver material to total area for modular systems 0 for continuous porous pavement systems. Note that porosity = void ratio / (1 + void ratio). Typical values for pavements are 0.12 to 0.21. The volume of void space relative to the volume of solids in the pavement for continuous systems or for the fill material used in modular systems. Typical values are 4 to 6 inches (100 to 150 mm). The thickness of the pavement layer (inches or mm). The Pavement Layer page of the LID Control Editor supplies values for the following properties of a porous pavement LID: The four layers used in a simulation for a Permeable Pavement LID are shown in the following image.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |