This calculator is intended to be used as a tool for quickly and generally investigating options for stormwater Best Management Practices (BMPs) for regulated developments under Chicago's Stormwater Management Ordinance (SMO) and other stormwater BMP applications in the city. It is not intended as a replacement to the worksheet in the SMO Manual. In the event that there are discrepencies between the calculator and the worksheet, the worksheet result should be used. You may view our Methodology here.

Calculator

Green BMPs

Green Roof
Amount (%):
Depth (in):
Porosity (Void Ratio):
Planter Boxes
Area (ft2):
Soil:
Depth (in):
Porosity (Void Ratio):
Underlying Aggregate:
Depth (in):
Porosity (Void Ratio):

Bioinfiltration System (Rain Garden)
Amount (ft2):
Prepared Soil:
Depth (in):
Porosity (Void Ratio):
Underlying Aggregate:
Depth (in):
Porosity (Void Ratio):
Native Vegetation
Amount (%):
Vegetation Filter Strips
Length (ft):
Width (in):
Depth of Prepared Soil (in):
Porosity of Prepared Soil:
Swales
Length (ft):
Top Width (in):
Width of Aggregate (in):
Depth of Aggregate (in):
Porosity of Aggregate:
Trees
Number:
Average Canopy (sq ft):

Permeable Pavement on Parking
Amount (%):
Material:
Underlying Aggregate:
Depth (in):
Porosity (Void Ratio):
Permeable Pavement on Driveways
Amount (%):
Material:
Underlying Aggregate:
Depth (in):
Porosity (Void Ratio):
Permeable Pavement on Sidewalks
Amount (%):
Material:
Underlying Aggregate:
Depth (in):
Porosity (Void Ratio):

Lot Information

Rainfall* (in) :
Soil Type*:
Size of Lot* (acres):
Or give dimensions.
Length of Lot (ft):
Width of Lot (ft):

Roof size+ (ft2):
Or give dimensions.
Roof Length (ft):
Roof Width (ft):
Number of Parking Spots+:
Parking Lot Size (ft2):
Number of Sides of Lot with Sidewalk+:
Driveway Dimensions+:
Length (ft):
Width (ft):

Advanced Options

Reset

* Must have these variables filled in.
+ Must have at least one of these variables filled in.