LID Rain Garden Control in #SWMM5 and #InfoSWMM for InfoSWMM Sustain

This is an introduction along with images of the LID Control and data require3ments in InfoSWMM. Every InfoSWMM Control uses from one to 5 layers of data - each with different data requirements. You can use the Siting Manger of InfoSWMM Sustain to find LID locations and the LID Optimizer to find the optimized number of units, cost of units, area and thickness of the LID layers based on your runoff and water quality control objectives.

Rain Gardens are a type of bio-retention cell consisting of just the engineered soil layer with no gravel bed below it. Rain Gardens are a type of bio-retention cell consisting of just the engineered soil layer with no gravel bed below it.Rain Gardens are shallow depressions filled with an engineered soil mix that supports vegetative growth. They are usually used on individual home lots to capture roof runoff. Typical soil depths range from 6 to 18 inches. The capture ratio is the ratio of the rain garden's area to the impervious area that drains onto it.

The Surface Process Layer consists of:

· The Storage Depth in inches or millimeters

· The Vegetative Cover Fraction (0 to 1),

· Surface Roughness (Manning’s n)

· Surface Slope (percent).

The Soil Process Layer consists of:

· Soil Thickness in inches or millimeters,

· Porosity as a Fraction (0 to 1),

· Field Capacity as a Fraction (0 to 1),

· Wilting Point as a Fraction (0 to 1),

· Conductivity (inches/hour or millimeters/hour),

· Conductivity Slope,

· Suction Head (inches/hour or millimeters/hour)

The two layers used in a simulation for a Rain Garden LID are shown in the following image.

Excerpt from the EPA manual Storm Water Management Model Reference Manual Volume III – Water Quality (PDF)  which can be found here

Excerpt from the EPA manual Storm Water Management Model Reference Manual Volume III – Water Quality (PDF)  which can be found here

See the topic Bio-Retention_Cell_LID_Reference_Values.htm for a discussion of parameter values for Rain Gardens.