Changes

[[File:Infiltration trench Honda.PNG|thumb|500px|Infiltration trench located at the Honda Campus, Markham, ON. Read about the performance of this practice in the [https://sustainabletechnologies.ca/app/uploads/2015/07/Honda_TechBrief_July2015.pdf technical brief] (Source: STEP, 2015)<ref>Hydrologic Assessment of LID Honda Campus, Markham, ON - TECHNICAL BRIEF. Accessed Dec 19 2022. https://sustainabletechnologies.ca/app/uploads/2015/07/Honda_TechBrief_July2015.pdf</ref>.]]

[[File:Image from StormTech.jpg|[[Infiltration chambers]] being installed (Source: StormTech, 2015).|thumb|500px|Read about the performance of this practice in the [https://sustainabletechnologies.ca/app/uploads/2013/03/Infiltration-Chambers-and-Trenches_2013-Final.pdf following final report published by STEP] (Source: Young et al. 2013<ref>Young, D. Van Seters, T., Graham, C. 2013. Evaluation of Underground Stormwater Infiltration Systems. Toronto and Region Conservation Authority. Toronto, Ontario. https://sustainabletechnologies.ca/app/uploads/2013/03/Infiltration-Chambers-and-Trenches_2013-Final.pdf</ref>).]]

===Notes===

===Notes===

* Designs include [[pretreatment]] through hydrodynamic separator ([[Oil and Grit Separator]]).

* Designs include [[pretreatment]] through hydrodynamic separator ([[Oil and Grit Separator]] and A "Sediment Trap" or Isolated chamber row).

* Operation and maintenance cost estimates assume rehabilitation of the filter media bed 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.  

** 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.

** The tool adds 10% contingency and additional overhead as default.

** The tool adds 10% contingency and additional overhead as default.

* All cost estimates are in Canadian dollars and represent the net present value (NPV) as the tool takes into account average annual interest and discount rates over the 25 and 50 year operating life cycle periods.

* All cost estimates are in Canadian dollars and represent the net present value (NPV) as the tool takes into account average annual interest and discount rates over the 25 and 50 year operating life cycle periods.

* Unit costs are based on 2018 RSMeans standard union pricing.

* Unit costs are based on 2018 RSMeans standard union pricing.

* Additional costs associated with retrofit or redevelopment contexts is assumed to be 16% of the cost estimate for new (greenfield) construction contexts.

* Additional costs associated with retrofit or redevelopment contexts is assumed to be 16% of the cost estimate for new (greenfield) construction contexts.

** Retrofit construction cost estimates are included in the 'Costs Summary' section for comparison.<br>

** Retrofit construction cost estimates are included in the 'Costs Summary' section for comparison.<br>

==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 Treatment''']]

[[File:ConstructionTable InfilChamb Full Infil.PNG|thumb|left|610px|'''Construction Costs Per Unit Drainage Area (CAD$/m²) - Full Infiltration Design, 25 mm Treatment''']]

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

Above you can find a cost breakdown of a 1000m² in two different configurations:<br>

Above you can find a cost breakdown of a 1000m² in two different configurations:<br>

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

#[[Infiltration chambers|Infiltration Chamber: Full Infiltration]]  

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

#[[Infiltration chambers|Infiltration Chamber: 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 (75%).

==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 the internal pipes every 10 years.  

Below are capital and life cycle cost estimates for the two [[Infiltration chambers|infiltration chamber]] 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 36% of total life cycle costs over the 25-year evaluation period, and increase to 48% of total life cycle costs over the 50-year period, due to increased levels of litter removal, clean out and disposal of collected sediment from the Isolated chamber row (every 4 - 8 years), cleaning out the catchbasin and the [[Oil and Grit Separator|Oil and Grit Separator/Hydrodynamic Separator]] annually.  

===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 InfilChamb Full Infil.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 InfilChamb Partial Infil.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 InfilChamb Full Infil.PNG|thumb|left|615px|'''Infiltration Chamber: Full Infiltration''']]

[[File:50yr LCCT InfilTrench Partial Infil.PNG|thumb|center|615px|'''Infiltration Trench: Partial Infiltration''']]

[[File:50yr LCCT InfilChamb Partial Infil.PNG|thumb|center|615px|'''Infiltration Chamber: 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 for the two [[Infiltration chambers|infiltration chamber]] configurations are the exact same with the total being ($60,831.76).<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:East Gwillimbury.png|800px|thumb|Example of "crate style" [[Infiltration chambers]] being installed in East Gwillimbury. Photo credit: [https://www.makeway.ca/products/stormwater-management-systems/ Make-Way Environmental Technologies Inc.]]

[[File:Design Table InfilTrench Full Infil.PNG|700px]]<br>

[[File:Design Table InfilChamb Full Infil.PNG|700px]]<br>

</br>

</br>

===Partial Infiltration===

===Partial Infiltration===

[[File:Design Table InfilTrench Partial Infil.PNG|700px]]<br>

[[File:Design Table InfilChamb Partial Infil.PNG|700px]]<br>

</br>

</br>

==References==

==References==