Low Impact Development Life Cycle Costing Tool

The msot recent version of the LID Life Cycle Costing Tool that was updated in December of 2021. (TRCA, 2019))

Overview

Accurately estimating the life cycle costs for low impact development (LID) practices can be a costly and time-consuming process. The LID life cycle costing tool (LCCT) facilitates this process and allows users to produce realistic cost estimates based on user-specified LID design and economic information. The LCCT provides cost estimates for the construction, inspection, and maintenance of LID stormwater practices.

Originally released in 2013, the most recent version of the excel-based tool (Version 3.0) includes the following new features and updates:

• Increased transparency and usability. Users can now access the tool’s back-end to modify assumptions, unit costs, design defaults, etc.
• Porous asphalt was added as a LID practice. Additionally, this tab allows for cost estimations for conventional asphalt so that direct comparisons can be made with LID practices.
• Cost estimation for dry ponds has been added to LID practices. Wet ponds are also included as a traditional stormwater management strategy in order to facilitate direct comparisons with LID.
• Updated line costs to 2018 based on RS Means data and information obtained through consultation with suppliers and project managers.
• Refined algorithms to reflect line cost updates and construction practices (i.e., Bioretention: Sizing:bioretention sizing algorithm based on latest guidance).
• Added a land value option to all BMPs. This allows users to account for land acquisition when required and for opportunity costs when otherwise developable land is used for stormwater management.
• Updated maintenance task schedules using “discretionary maintenance options” and defaults that were based on observations in the field.
• Added a costing curve development module that enables users to develop their own costing curves to be input into the LID-TTT.
• A sensitivity analysis that uses constructed projects to test the tool’s accuracy.
• An LCCT user guide provides a brief introduction to the tool and a demonstration of how it can be used to suit their purposes.
• The LID practices evaluated in the report include bioretention cells, permeable pavement, infiltration trenches and infiltration chambers, enhanced swales, rainwater harvesting and green roofs.  bioswales and perforated pipe systems or exfiltration trenches were considered to be similar to bioretention and infiltration trenches, respectively, and therefore were not evaluated as separate practices.  The tool does not assess LID-related cost savings related to improved aesthetics, air quality, community livability and other public benefits, as these savings are best evaluated in relation to specific case study examples.

STEP encourages feedback on the LCCT from users and they can provide them below on this page or here at the team's email address: STEP@trca.ca

Low Impact Development. A stormwater management strategy that seeks to mitigate the impacts of increased urban runoff and stormwater pollution by managing it as close to its source as possible. It comprises a set of site design approaches and small scale stormwater management practices that promote the use of natural systems for infiltration and evapotranspiration, and rainwater harvesting.

Toronto and Region Conservation Authority

A stormwater management strategy that seeks to mitigate the impacts of increased urban runoff and stormwater pollution by managing it as close to its source as possible. It comprises a set of site design approaches and small scale stormwater management practices that promote the use of natural systems for infiltration and evapotranspiration, and rainwater harvesting.

A mixture of mineral aggregates bound with bituminous materials, used in the construction and maintenance of paved surfaces.

A shallow excavated surface depression containing prepared filter media, mulch, and planted with selected vegetation.

Sustainable Technologies Evaluation Program

Low impact development is a stormwater management and land development strategy applied at the parcel and subdivision scale that emphasizes conservation and use of on-site natural features integrated with engineered, small scale hydrologic controls to more closely mimic pre-development hydrologic functions.

A stormwater management strategy that seeks to mitigate the impacts of increased urban runoff and stormwater pollution by managing it as close to its source as possible. It comprises a set of site design approaches and small scale stormwater management practices that promote the use of natural systems for infiltration and evapotranspiration, and rainwater harvesting.