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| * Trench width of 2.0 metres. | | * Trench width of 2.0 metres. |
| * 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. |
− | * Trench depth of 580 mm and surface area of 198.73 m2 (I:P area ratio of 10:1) on 20 mm/h native soil (Full Infiltration Design) | + | * Trench depth of 580 mm and surface area of 198.73 m<sup>2</sup> (I:P area ratio of 10:1) on 20 mm/h native soil (Full Infiltration Design) |
− | * Trench depth of 290 mm and surface area of 366.58 m2 (I:P area ratio of 5.5:1) on 10 mm/h native soil (Partial Infiltration Design) | + | * Trench depth of 290 mm and surface area of 366.58 m<sup>2</sup> (I:P area ratio of 5.5:1) on 10 mm/h native soil (Partial Infiltration Design) |
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| ===Notes=== | | ===Notes=== |
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| ==Construction Costs== | | ==Construction Costs== |
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− | [[File:ConstructionTable InfilTrench Full Infil.PNG|thumb|left|615px|'''Construction Costs Per Unit Drainage Area (CAD$/m<sup>2</sup>) - Full Infiltration Design, 25 mm Retention''']] | + | [[File:ConstructionTable InfilTrench Full Infil 2023.PNG|thumb|left|615px|'''Construction Costs Per Unit Drainage Area (CAD$/m<sup>2</sup>) - Full Infiltration Design, 25 mm Retention''']] |
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| [[File:ConstructionTable InfilTrench Partial Infil.PNG|thumb|center|615px|'''Construction Costs Per Unit Drainage Area (CAD$/m<sup>2</sup>) - Partial Infiltration Design, 25 mm Retention''']] | | [[File:ConstructionTable InfilTrench Partial Infil.PNG|thumb|center|615px|'''Construction Costs Per Unit Drainage Area (CAD$/m<sup>2</sup>) - Partial Infiltration Design, 25 mm Retention''']] |
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− | <small>'''Note:''' Please click on each image to enlarge to view associated construction cost estimates.</small><br> | + | <small>'''Note:''' Click on each image to enlarge to view associated construction cost estimates.</small><br> |
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| + | Above you can find breakdowns of construction costs by expense type for each infiltration trench design scenario:<br> |
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− | Above you can find a cost breakdown of a 1000m<sup>2</sup> in two different configurations:<br>
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| #[[Infiltration trenches|Infiltration Trench: Full Infiltration]] | | #[[Infiltration trenches|Infiltration Trench: Full Infiltration]] |
| #[[Infiltration trenches|Infiltration Trench: Partial Infiltration]] | | #[[Infiltration trenches|Infiltration Trench: Partial Infiltration]] |
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− | As can be seen, regardless of design configuration, Material & Installation expenses represent the largest portion of total construction costs (75 to 76%). | + | As can be seen, regardless of design configuration, Material & Installation expenses represent the largest portion of total construction costs (76%). |
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| ==Life Cycle Costs== | | ==Life Cycle Costs== |
− | Below are capital and life cycle cost estimates for the two [[Infiltration trenches|infiltration trench]] configurations 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 38% of total life cycle costs over the 25-year evaluation period, and increase to 51% of total life cycle costs over the 50-year period, due to increased levels of litter removal, replacement of filter cloth and disposal of collected sediment (every 4 - 8 years), cleaning out the catchbasin and the [[Oil and Grit Separator|Oil and Grit Separator/Hydrodynamic Separator]] annually, as well as flushing inlet, distribution and outlet pipes every 10 years. | + | Below are capital and life cycle cost estimates for the two [[Infiltration trenches|infiltration trench]] configurations 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 52% of total life cycle costs over the 50-year period, due flushing of inlet, distribution and outlet pipes every 10 years. |
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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 InfilTrench Full Infil.PNG|thumb|left|615px|'''Infiltration Trench: Full Infiltration''']] | + | [[File:25yr LCCT InfilTrench Full Infil 2023.PNG|thumb|left|615px|'''Infiltration Trench: Full Infiltration''']] |
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− | [[File:25yr LCCT InfilTrench Partial Infil.PNG|thumb|center|615px|'''Infiltration Trench: Partial Infiltration''']] | + | [[File:25yr LCCT InfilTrench Partial Infil 2023.PNG|thumb|center|615px|'''Infiltration Trench: Partial Infiltration''']] |
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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 InfilTrench Full Infil.PNG|thumb|left|615px|'''Infiltration Trench: Full Infiltration''']] | + | [[File:50yr LCCT InfilTrench Full Infil 2023.PNG|thumb|left|615px|'''Infiltration Trench: Full Infiltration''']] |
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− | [[File:50yr LCCT InfilTrench Partial Infil.PNG|thumb|center|615px|'''Infiltration Trench: Partial Infiltration''']] | + | [[File:50yr LCCT InfilTrench Partial Infil 2023.PNG|thumb|center|615px|'''Infiltration Trench: Partial Infiltration''']] |
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| ==Cost Summary Tables== | | ==Cost Summary Tables== |
− | Total life cycle cost estimates for the two [[Infiltration trenches|infiltration trench]] configurations vary substantially with the [[Infiltration trenches|Infiltration Trench: Partial Infiltration]] design being highest ($85,288.88), followed closely by the [[Infiltration trenches|Infiltration Trench: Full Infiltration]] design being ($69,805.90).<br> | + | Total life cycle cost estimates over the 50 year evaluation period for the two [[Infiltration trenches|infiltration trench]] design configurations vary substantially with the [[Infiltration trenches|Infiltration Trench: Partial Infiltration]] design being highest ($183.197.71), followed closely by the [[Infiltration trenches|Infiltration Trench: Full Infiltration]] design being ($150,128.87).<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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| ===Full Infiltration=== | | ===Full Infiltration=== |
− | [[File:North Dakota State U infiltration trench.jpg|800px|thumb|Good use of geotextile, being limited to preventing fines from entering the trench from above. Read more about the performance of this feature in comparison to [[bioretention]]] BMPs 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:North Dakota State U infiltration trench.jpg|thumb|1000px|Good use of geotextile, being limited to preventing fines from entering the trench from above. Read about the performance of infiltration trenches in comparison to [[bioretention]]. (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>)]] |
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− | [[File:Design Table InfilTrench Full Infil.PNG|700px]]<br> | + | [[File:Design Table InfilTrench Full Infil 2023.PNG|700px]]<br> |
| </br> | | </br> |
| + | |
| ===Partial Infiltration=== | | ===Partial Infiltration=== |
− | [[File:Design Table InfilTrench Partial Infil.PNG|700px]]<br> | + | [[File:Design Table InfilTrench Partial Infil 2023.PNG|700px]]<br> |
| </br> | | </br> |
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| ==References== | | ==References== |