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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 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, 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 (where applicable) | + | * 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. |
| *Maximum impervious drainage area to permeable surface area (I:P area) ratio of 20:1. | | *Maximum impervious drainage area to permeable surface area (I:P area) ratio of 20:1. |
| * Length to width ratio of bioretention area is 10:1. | | * Length to width ratio of bioretention area is 10:1. |
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| ==Cost Summary Tables== | | ==Cost Summary Tables== |
− | Total life cycle cost estimates for the three [[Bioretention]] configurations vary substantially with the [[Bioretention: Partial infiltration| Partial Infiltration]] design being highest ($113,800.83), followed closely by [[Stormwater planter| No Infiltration]] design ($109,113.76), and [[Bioretention: Full infiltration| Full Infiltration]] design being the lowest ($80,392.33).<br> | + | Total life cycle cost estimates over the 50 year evaluation period for the three [[Bioretention]] configurations vary substantially with the [[Bioretention: Partial infiltration| Partial Infiltration]] design being highest ($190,132.53), followed closely by [[Stormwater planter| No Infiltration]] design ($185,304.84), and [[Bioretention: Full infiltration| Full Infiltration]] design being the lowest ($153,805.69).<br> |
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| It is notable that a sensitivity analysis was conducted in 2019 to compare construction cost estimates generated by the tool to actual costs of implemented projects. '''The analysis found that tool estimates were typically within ±14% of actual construction costs'''<ref>Credit Vally Conservation (CVC). 2019. Life-cycle costing tool 2019 update: sensitivity analysis. Credit Valley Conservation, Mississauga, Ontario. https://sustainabletechnologies.ca/app/uploads/2020/04/LCCT-Sensitivity-Analysis_March2020.pdf</ref> | | It is notable that a sensitivity analysis was conducted in 2019 to compare construction cost estimates generated by the tool to actual costs of implemented projects. '''The analysis found that tool estimates were typically within ±14% of actual construction costs'''<ref>Credit Vally Conservation (CVC). 2019. Life-cycle costing tool 2019 update: sensitivity analysis. Credit Valley Conservation, Mississauga, Ontario. https://sustainabletechnologies.ca/app/uploads/2020/04/LCCT-Sensitivity-Analysis_March2020.pdf</ref> |
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| [[File:Picture for page.PNG|thumb|700px|STEP staff member conducting performance analysis of a bioretention feature at Kortright Centre in Vaughan, ON. (Source: STEP, 2016<ref>Performance Comparison of Surface and Underground Stormwater Infiltration Practices - TECHNICAL BRIEF. Low Impact Development Series. https://sustainabletechnologies.ca/app/uploads/2016/08/BioVSTrench_TechBrief__July2015.pdf</ref>)]] | | [[File:Picture for page.PNG|thumb|700px|STEP staff member conducting performance analysis of a bioretention feature at Kortright Centre in Vaughan, ON. (Source: STEP, 2016<ref>Performance Comparison of Surface and Underground Stormwater Infiltration Practices - TECHNICAL BRIEF. Low Impact Development Series. https://sustainabletechnologies.ca/app/uploads/2016/08/BioVSTrench_TechBrief__July2015.pdf</ref>)]] |
| | | |
− | [[File:Design Table Bio Full Infil Update.PNG|700px]]<br> | + | [[File:Design Table Bio Full Infil Update 2023.PNG|700px]]<br> |
| </br> | | </br> |
| | | |
| ===Partial Infiltration=== | | ===Partial Infiltration=== |
− | [[File:Design Table Bio Partial Infil update.PNG|700px]]<br> | + | [[File:Design Table Bio Partial Infil update 2023.PNG|700px]]<br> |
| </br> | | </br> |
| | | |
| ===No Infiltration (Filtration Only)=== | | ===No Infiltration (Filtration Only)=== |
− | [[File:Design Table Bio No Infil Update.PNG|700px]]<br> | + | [[File:Design Table Bio No Infil Update 2023.PNG|700px]]<br> |
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| ==References== | | ==References== |