Changes

*Operation and maintenance (O&M) cost estimates assume annual inspections, removal of trash and debris twice a year, vacuum sweeping annually, and removal of weeds twice a year. Verification inspections are included every 5 years to confirm adequate maintenance, and every 15 years to confirm adequate drainage performance through in-situ surface infiltration rate testing.

*Operation and maintenance (O&M) cost estimates assume annual inspections, removal of trash and debris twice a year, vacuum sweeping annually, and removal of weeds twice a year. Verification inspections are included every 5 years to confirm adequate maintenance, and every 15 years to confirm adequate drainage performance through in-situ surface infiltration rate testing.

* Impervious drainage area to permeable surface area (I:P area) ratio of 1:1

* Impervious drainage area to permeable surface area (I:P area) ratio of 1:1

* Default Bedding depth of 50 millimetres.

* Default Bedding (2 to 5 mm dia. clear stone) depth of 50 millimetres.

* Default Base depth of 100 millimetres.

* Default Base (20 mm dia. clear stone) depth of 100 millimetres.

* Default Sub-base depth (50 mm dia. clear stone) of 200 millimetres.

* Default Sub-base (50 mm dia. clear stone) depth of 200 millimetres.

* A 150 mm diameter perforated underdrain pipe is included in Partial Infiltration and No Infiltration design configurations only.<br>

* A 150 mm diameter perforated underdrain pipe is included in Partial Infiltration and No Infiltration design configurations only.<br>