Changes

* 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.

===Notes===

===Notes===

* Designs include [[pretreatment]] through two (2) hydrodynamic separators ([[Oil and Grit Separator]]) located upstream of trench inlets, and two (2) 150 mm diameter monitoring wells per trench.

* Designs include [[pretreatment]] through two (2) hydrodynamic separators (i.e., [[Oil and Grit Separator| oil and grit separators]]) located upstream of trench inlets, and two (2) 150 mm diameter monitoring wells per trench.

* 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.

==Construction Costs==

==Construction Costs==

[[File:ConstructionTable InfilTrench Full Infil.PNG|thumb|left|615px|'''Construction Costs Per Unit Drainage Area (CAD$/m²) - Full Infiltration Design, 25 mm Retention''']]

[[File:ConstructionTable InfilTrench Full Infil 2023.PNG|thumb|left|615px|'''Construction Costs Per Unit Drainage Area (CAD$/m²) - Full Infiltration Design, 25 mm Retention''']]

[[File:ConstructionTable InfilTrench Partial Infil.PNG|thumb|center|615px|'''Construction Costs Per Unit Drainage Area (CAD$/m²) - Partial Infiltration Design, 25 mm Retention''']]

[[File:ConstructionTable InfilTrench Partial Infil.PNG|thumb|center|615px|'''Construction Costs Per Unit Drainage Area (CAD$/m²) - Partial Infiltration Design, 25 mm Retention''']]

<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>

#[[Infiltration trenches|Infiltration Trench: Full Infiltration]]  

#[[Infiltration trenches|Infiltration Trench: Full Infiltration]]  

#[[Infiltration trenches|Infiltration Trench: Partial Infiltration]]

#[[Infiltration trenches|Infiltration Trench: Partial Infiltration]]

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%).

==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.  

===25-Year life cycle cost break down===

===25-Year life cycle cost break down===

[[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''']]

[[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''']]

===50-Year life cycle cost break down===

===50-Year life cycle cost break down===

[[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''']]

[[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''']]

==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>

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>

===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>)]]

[[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>

==References==

==References==