Changes

As the maximum flow rate exceeds the downstream maximum permissible flow, the design must be amended. In order of preference, some options include:

As the maximum flow rate exceeds the downstream maximum permissible flow, the design must be amended. In order of preference, some options include:

#Increasing the size of the downstream pipe to accommodate a greater flow rate;

#Increasing the size of the downstream pipe to accommodate a greater flow rate;

#Reducing the depth of the filter media bed in agreement with a Landscape Architect, and increasing pretreatment (as filter bed < 600 mmm will provide less treatment); or   

#Reducing the depth of the filter media bed in agreement with a Landscape Architect, and increasing pretreatment (as filter bed < 600 mm deep will provide less water quality treatment); or   

#Reformulating the bioretention filter media in collaboration with the soils provider, to reduce the hydraulic conductivity.

#Reformulating the bioretention filter media in collaboration with the soils provider, to reduce the hydraulic conductivity.