Author(s): Leonardo Nania, Oswaldo Torres, Marcelo H. García
Keywords: Green infrastructure; Runoff-reducingmeasures; Dual drainage; Hydrologicmodel; Hydraulicmodel; Urban catchment; Street runoff; Rain barrel; Green roof; Pervious pavement; Chicago;
Green Infrastructure (GI) is commonly used to reduce runoff in general in urban areas. However, there is a lack of methodologies to assess its effectiveness. Herein, three types of green infrastructure (GI): rain barrels, green roofs and pervious pavements are implemented in a Dual Drainage Model (DDM) for a catchment in the Metropolitan Area of Chicago (IL); with an extension of approximately 31 Km2 and using the 100-year return period and 3-hr design storm. The three GI are applied in an equal proportion to existing impermeable areas of the blocks (5%, each). The results show that rain barrels have little influence in runoff reduction (less than 0.5%) while pervious pavements produce a reduction in runoff of 7.47% while green roofs result in a 5.66% reduction. When all GI are implemented a reduction of 13.44%is achieved almost as high as with green roofs plus pervious pavements. The reductions in number of streets affected by a hazard criterion based on water depths (greater than 0.3m) is only 27 (Total number of streets: 7104) using rain barrels, 134 for green roofs and 149 for pervious pavements. Using both green roofs and pavements the reduction is 245, similar to using all GI simultaneously.