City of Columbus, Ohio submitted the integrated plan, branded as “Blueprint Columbus” to Ohio EPA in 2015 to meet city’s consent orders requirements. This updated Wet Weather Management Plan follows USEPA’s integrated planning memo and proposed green infrastructures (GI) as part of the overall wet weather management solution. To develop scientifically sound design criteria for green infrastructures, a rigorous investigation of current policies and practices related to GI was performed. Six pilot areas (total of 1,000 acres) were chosen and different design levels of service were compared. Design criteria of water quality, quantity, flood protection and hydromodification were comprehensively evaluated.
Along with the determination of design criteria, stormwater models were constructed for the pilot areas and various modeling approaches were investigated to demonstrate design requirements compliance. This paper is to summarize the process of developing the GI design criteria, the stormwater modeling approaches and the associated challenges and findings. Further refinement of the design criteria and modeling approaches are also discussed as four additional Blueprint projects were in place and more experience was gained.