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| 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 rate for Full Infiltration Design scenario was assumed to be 20 mm/h, and a safety factor of 2.5 was applied to calculate the design infiltration rate. | + | * Native soil infiltration rate for Full Infiltration Design scenario was assumed to be 20 mm/h, 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, removal of sediment from outlet catch basin 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. | + | * Ditch inlet catch basin structure located at furthest downgradient end, with connection to storm sewer pipe, included as the outlet. |
| + | * Operation and maintenance (O&M) cost estimates assume annual inspections, removal of trash and debris twice a year, removal of sediment from curb inlets and outlet catch basin 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 pervious swale footprint area of 10:1 (tool default value). | | * Impervious drainage area to pervious swale footprint area of 10:1 (tool default value). |
| * Designed with a trapezoidal cross section with a top width of 4.75 m, bottom width of 0.75 m, and 2.5:1 side slopes (tool default values). | | * Designed with a trapezoidal cross section with a top width of 4.75 m, bottom width of 0.75 m, and 2.5:1 side slopes (tool default values). |
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| ===Notes=== | | ===Notes=== |
− | * Design includes [[pretreatment]] through stone diaphragms at [[Curb cuts|curb inlets]], and ditch inlet catch basin structure located at furthest downgradient end, with connection to storm sewer pipe, as the outlet. | + | * Design includes [[pretreatment]] through stone diaphragms at [[Curb cuts|curb inlets]]. |
| * Operation and maintenance cost estimates assume rehabilitation of the swale surface is required after 25 years of operation. | | * Operation and maintenance cost estimates assume rehabilitation of the swale surface is required after 25 years of operation. |
| * 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. |
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| ==Construction Costs== | | ==Construction Costs== |
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− | [[File:Construction Breakdown EnhancedSwales Full Infil.PNG|thumb|center|950px|'''Construction Costs Per Unit Drainage Area (CAD$/m<sup>2</sup>) - Full Infiltration Design, 25 mm Treatment''']] | + | [[File:Construction Breakdown EnhancedSwales Full Infil 2023.PNG|thumb|center|950px|'''Construction Costs Per Unit Drainage Area (CAD$/m<sup>2</sup>) - Full Infiltration Design, 25 mm Treatment''']] |
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| ==Life Cycle Costs== | | ==Life Cycle Costs== |
− | Below are capital and life cycle cost estimates for the [[Enhanced swales]] Full Infiltration configuration over 25- and 50-year time periods. The estimates of maintenance and rehabilitation (life cycle) costs represent net present values. Operation and maintenance costs are predicted to represent 45% of total life cycle costs over the 25-year evaluation period, and increase to 59% of total life cycle costs over the 50-year period, due to increased levels of litter removal, watering (establishment period - years 1 & 2 / annually and / drought watering) cleaning out and vacuuming of the catchbasin, mowing, replacement of sod, weeding and pruning of the BMP's planted [[vegetation]]. | + | Below are capital and life cycle cost estimates for the [[Enhanced swales]] Full Infiltration configuration over 25- and 50-year time periods. The estimates of maintenance and rehabilitation (life cycle) costs represent net present values. Operation and maintenance costs are predicted to represent 39% of total life cycle costs over the 25-year evaluation period, and increase to 54% of total life cycle costs over the 50-year period, due to swale surface rehabilitation costs assumed to be required after 25 years of operation. |
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| ===25-Year life cycle cost break down=== | | ===25-Year life cycle cost break down=== |
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− | [[File:25yr LCCT EnhancedSwales Full Infil.PNG|thumb|center|900px|'''Enhanced Swales: Full Infiltration''']] | + | [[File:25yr LCCT EnhancedSwales Full Infil 2023.PNG|thumb|center|900px|'''Enhanced Swales: Full Infiltration''']] |
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| <small>'''Note:''' Click on each image to enlarge to view associated life cycle cost estimate.</small><br> | | <small>'''Note:''' Click on each image to enlarge to view associated life cycle cost estimate.</small><br> |
| + | </br> |
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| ===50-Year life cycle cost break down=== | | ===50-Year life cycle cost break down=== |
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− | [[File:50yr LCCT EnhancedSwales Full Infil.PNG|thumb|center|900px|'''Enhanced Swales: Full Infiltration''']] | + | [[File:50yr LCCT EnhancedSwales Full Infil 2023.PNG|thumb|center|900px|'''Enhanced Swales: Full Infiltration''']] |
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| <small>'''Note:''' Click on each image to enlarge to view associated life cycle cost estimate.</small><br> | | <small>'''Note:''' Click on each image to enlarge to view associated life cycle cost estimate.</small><br> |
| + | </br> |
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| ==Cost Summary Tables== | | ==Cost Summary Tables== |
− | Total life cycle cost estimates for the [[Enhanced swale]] Full Infiltration design configuration is ($23,451.36), makign it one of the cheapest LID BMP options.<br> | + | Total life cycle cost estimate over the 50 year evaluation period for the [[Enhanced swale]] Full Infiltration design configuration is ($65,021.40), making it one of the cheapest LID BMP options.<br> |
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| ===Full Infiltration=== | | ===Full Infiltration=== |
− | [[File:CVC Office, Grass Swale.JPG|500px|thumb|Enhanced Grass [[swale]] in CVC headquarters parking lot, Mississauga ON.]] | + | [[File:CVC Office, Grass Swale.JPG|650px|thumb|Enhanced Grass [[swale]] in CVC headquarters parking lot, Mississauga ON.]] |
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− | [[File:Design Table EnhancedSwales Full Infil.PNG|700px]]<br> | + | [[File:Design Table EnhancedSwales Full Infil 2023.PNG|700px]]<br> |
| </br> | | </br> |