Changes

|''q''||mm/hr||Infiltration coefficient, calculated from measured [[Infiltration: Testing| infiltration rate]] and applied [[Infiltration|safety factor]]

|''q''||mm/hr||Infiltration coefficient, calculated from measured [[Infiltration: Testing| infiltration rate]] and applied [[Infiltration|safety factor]]

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|''n''||-||Porosity, as measured (or default to 0.35). *Note: For systems that have significant storage in clear open chambers, an effective porosity value (''n<nowiki>'</nowiki>'') may be estimated for the whole installation and applied to these calculations. The effective porosity will vary according to the geometry of the storage chambers and advice should be sought from product manufacturers. Permit applications should include information which has been used as the basis for such calculations.

|''n''||-||Porosity, as measured (or default to 0.35).<br> *Note: For systems that have significant storage in clear open chambers, an effective porosity value (''n<nowiki>'</nowiki>'') may be estimated for the whole installation and applied to these calculations. The effective porosity will vary according to the geometry of the storage chambers and advice should be sought from product manufacturers. Permit applications should include information which has been used to estimate ''n<nowiki>'</nowiki>''.

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|''I''||m²||Impermeable area i.e. catchment

|''I''||m²||Impermeable area i.e. catchment