Changes

Design and operation and maintenance program assumptions used to generate cost estimates are based on tool default values and the following STEP recommendations:

Design and operation and maintenance program assumptions used to generate cost estimates are based on tool default values and the following STEP recommendations:

*Native soil infiltration rates for Full, Partial and No Infiltration Design scenarios were assumed to be 20 mm/h, 10 mm/h and 2 mm/h, respectively, and a safety factor of 2.5 was applied to calculate the design infiltration rate.

*Native soil infiltration rates for Full, Partial and No Infiltration Design scenarios were assumed to be 20 mm/h, 10 mm/h and 2 mm/h, respectively, and a safety factor of 2.5 was applied to calculate the design infiltration rate.

*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, and vacuum sweeping annually. 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 (2 to 5 mm dia. clear stone) depth of 50 millimetres.

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

===Notes===

===Notes===

* Operation and maintenance cost estimates include replacement of joint stabilizing aggregate material removed by vacuum sweeping.

* Operation and maintenance cost estimates include replacement of joint stabilizing aggregate material removed by vacuum sweeping and assume no rehabilitation of the permeable pavement surface is required over the 50 year timeframe.

* The tool calculates costs for new (greenfield) development contexts and includes costs for contractor overhead and profit, material, delivery, labour, equipment (rental, operating and operator costs), hauling and disposal.  

* The tool calculates costs for new (greenfield) development contexts and includes costs for contractor overhead and profit, material, delivery, labour, equipment (rental, operating and operator costs), hauling and disposal.  

** Land value and equipment mobilization and demobilization costs are not included, assuming BMP construction is part of overall development site construction.

** Land value and equipment mobilization and demobilization costs are not included, assuming BMP construction is part of overall development site construction.