Changes

|''i''||mm/h||Intensity of design storm

|''i''||mm/h||Intensity of design storm

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|''f'''||mm/h||Design infiltration rate of the underlying native soil, calculated from measured [[Infiltration: Testing| infiltration rate]] and applied [[Infiltration|safety factor]]

|''f'''||mm/h||[[Design infiltration rate]] of the underlying native soil, calculated from measured [[Infiltration: Testing| infiltration rate]] and applied [[Infiltration|safety factor]]

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|''n''||-||Porosity of the aggregate or other void-forming fill material(s) in the storage reservoir of the practice.<br> *Note: For systems that have significant storage in open chambers surrounded by clear stone aggregate, an effective porosity value (''n<nowiki>'</nowiki>'') may be estimated for the whole installation and used in the calculations below. Effective porosity will vary according to the geometry of the storage chambers, so advice should be sought from product manufacturers. Permit applications should include the basis for ''n<nowiki>'</nowiki>'' estimates.

|''n''||-||Porosity of the aggregate or other void-forming fill material(s) in the storage reservoir of the practice.<br> *Note: For systems that have significant storage in open chambers surrounded by clear stone aggregate, an effective porosity value (''n<nowiki>'</nowiki>'') may be estimated for the whole installation and used in the calculations below. Effective porosity will vary according to the geometry of the storage chambers, so advice should be sought from product manufacturers. Permit applications should include the basis for ''n<nowiki>'</nowiki>'' estimates.