Shades of Green: Using SWMM LID Controls to Simulate Green Infrastructure

Green infrastructure is increasingly being considered for application in urban storm water management designs. Many municipalities, regulatory agencies and advocacy groups promote the use of low impact development (LID) to reduce runoff and increase infiltration. To show LID benefits, engineers must quantify the advantages of green versus traditional grey infrastructure. The United States Environmental Protection Agency (USEPA) updated its Storm Water Management Model (SWMM) with explicit LID controls in 2009 to assist engineers in quantifying green infrastructure benefits SWMM can now simulate five LID devices: bioretention cells; infiltration trenches; porous pavements; rain barrels; and vegetated swales.