Changes

|Thickness (mm)||Entire trench

|Thickness (mm)||Entire trench

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|Void ratio||Suggest range 0.35 – 0.4 (unless otherwise tested) for designs using just aggregates for storage. For any design using preformed infiltration chambers, the overall ‘effective void ratio’ will vary according to product geometry. Contact manufacturer(s) for recommended value.   

|Void ratio||Suggest value 0.4 (unless otherwise tested) for designs using just clear stone [[reservoir aggregate]] for storage. For any design using preformed [[infiltration chambers]], the overall ‘effective void ratio’ will vary according to product geometry. Contact manufacturer(s) for recommended value.   

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|Seepage rate (mm/hr)||Infiltration rate of native soil  

|Seepage rate (mm/hr)||Infiltration rate of native soil. See [[design infiltration rate]]

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|Clogging factor||?

|Clogging factor||Typical value of 0.5 for aged structures.

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|Design drawdown time (hrs)||Recommend 48 hours?

|Design drawdown time (hrs)||Suggested value 72 - 96 hours, see [[drainage time]]

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!colspan = "2" style="background: darkcyan; color: white; align = center"|Drain (underdrain)

!colspan = "2" style="background: darkcyan; color: white; align = center"|Drain (underdrain)