SPU DWW Swales

The DWW (Drainage and Waste Water) GSI (Green Stormwater Infrastructure) layer consists of line and polygon representations of the following features: Swales (biofiltration, bioretention, biofiltration/bioretention, and conveyance) are generally shallow depressions with a designed mix of soil and plants which break down pollutants through natural processes while reducing runoff. Permeable pavement is a paving system which allows rainfall to percolate into an underlying soil or aggregate storage reservoir. Underdrain piping systems are provided to prevent prolonged ponding of stormwater or to collect and convey water to another facility. Rain gardens are less engineered systems that are designed to mitigate water from the sidewalk only and have two inches or less of ponded depth. The drainage structures represented in the GSI points are not all unique to GSI, however, they are specifically part of SPU GSI projects.