Changes

Jump to navigation Jump to search
Line 37: Line 37:  
*[[Green Roof: Life Cycle Costs]]
 
*[[Green Roof: Life Cycle Costs]]
   −
<small>'''Note''': All practice cost estimates are based on a Contributing Drainage Area (CDA) of 2,000 m<sup>2</sup>, runoff control target of 25 mm depth (retention or treatment), and a drainage period of 72 hours. For infiltration practices, 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. Construction cost estimates assume the practice is built as part of an overall greenfield site construction project so do not include land value, equipment mobilization/demobilization costs, nor additional costs associated with retrofit/redevelopment scenarios.  Operation and maintenance (O&M) cost estimates assume annual inspections, removal of trash and debris twice a year, removal of sediment from pretreatment structures annually, and removal of weeds twice a year (where applicable). 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 (bioretention, enhanced swales, permeable pavers and porous asphalt) or natural storm event testing (infiltration chambers and trenches).</small>
+
<small>'''Note''': All practice cost estimates are based on a Contributing Drainage Area (CDA) of 2,000 m<sup>2</sup>, runoff control target of 25 mm depth (retention or treatment), and a drainage period of 72 hours. For infiltration practices, 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. Construction cost estimates assume the practice is built as part of an overall greenfield site construction project so do not include land value, equipment mobilization/demobilization costs, nor additional costs associated with retrofit/redevelopment scenarios.  Operation and maintenance (O&M) cost estimates assume annual inspections, removal of trash and debris twice a year, removal of sediment from pretreatment structures annually, and removal of weeds twice a year (where applicable). 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 (bioretention, enhanced swales, permeable pavers and porous asphalt) or natural storm event testing (infiltration chambers and trenches).</small>
    
==Comparison of Life Cycle Costs by BMP Type==
 
==Comparison of Life Cycle Costs by BMP Type==

Navigation menu