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==Overview==
==Overview==
Given that [[Bioretention]] is a widely used name and a general "catch-all" term for most vegetated LID practices that temporarily store stormwater runoff in depressed planting beds there are a number of configurations of the feature that can be used in various contexts and environments. Depending on native soil infiltration rate and physical constraints, the facility may be designed without an [[underdrain]] for [[Bioretention: Full infiltration|full infiltration]], with an underdrain for [[Bioretention: Partial infiltration|partial infiltration]], or with an impermeable [[liner]] and underdrain for [[Stormwater planters|no infiltration/filtration only]] (i.e., [[stormwater planters]] or biofilter) design. STEP has prepared life cycle costs estimates for each design configuration, based on a 2,000 m<sup>2</sup> asphalt drainage area, runoff control target of 25 mm depth and 72 hour drainage period, for comparison which can be viewed below. To generate your own life cycle cost estimates customized to the development context, design criteria, and constraints applicable to your site, access the updated [https://sustainabletechnologies.ca/lid-lcct/ LID Life Cycle Costing Tool (LCCT) here].
Given that [[Bioretention]] is a widely used name and a general "catch-all" term for most vegetated LID practices that temporarily store stormwater runoff in depressed planting beds there are a number of configurations of the feature that can be used in various contexts and environments. Depending on native soil infiltration rate and physical constraints, the facility may be designed without an [[underdrain]] for [[Bioretention: Full infiltration|full infiltration]], with an underdrain for [[Bioretention: Partial infiltration|partial infiltration]], or with an impermeable [[liner]] and underdrain for [[Stormwater planters|no infiltration/filtration only]] (i.e., a [[stormwater planters]] or biofilter) design. STEP has prepared life cycle costs estimates for each design configuration, based on a 2,000 m<sup>2</sup> asphalt drainage area, runoff control target of 25 mm depth and 72 hour drainage period, for comparison which can be viewed below. To generate your own life cycle cost estimates customized to the development context, design criteria, and constraints applicable to your site, access the updated [https://sustainabletechnologies.ca/lid-lcct/ LID Life Cycle Costing Tool (LCCT) here].
==Design Assumptions==
==Design Assumptions==
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* 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 contents is assumed to be 16% higher than the cost for new (greenfield) development 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>
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#[[Bioretention: Full infiltration]]
#[[Bioretention: Full infiltration]]
#[[Bioretention: Partial infiltration]]
#[[Bioretention: Partial infiltration]]
#[[Stormwater planters| Bioretention: No infiltration]],
#[[Stormwater planters| Bioretention: No infiltration]]
As can be seen, regardless of design configuration, Material & Installation expenses represent the largest portion of total construction costs (75 to 79%).
As can be seen, regardless of design configuration, Material & Installation expenses represent the largest portion of total construction costs (75 to 79%).