Low impact development treatment train tool

Screenshot of the LID TTT

Menu bar of the LID TTT

The Low Impact Development Treatment Train Tool (LID TTT) is designed to help developers, consultants, municipalities and landowners understand and implement more sustainable stormwater management planning and design practices in their watersheds.

The LID TTT focuses on the use of Low Impact Development best management practices (BMPs) to meet stormwater management criteria for the site and can be used to:

• analyze annual and event based runoff volumes,
  • including water budget information: surface evapotranspiration, surface runoff, and infiltration to soil
• provide estimates of water quality improvements.

The LID TTT is built upon the open source EPA SWMM5 hydrologic model providing a user-friendly interface for novice modelers and cross-compatibility with SWMM5 for further model development.

The LID TTT has been developed in partnership between Lake Simcoe Region Conservation Authority, Credit Valley Conservation, and Toronto and Region Conservation Authority.

Integration with this guide is through suggested 'starting point' values for design parameters for the following BMP types:

• Bioretention
• Vegetated filter strips
• Infiltration trenches
• Permeable pavements
• Rainwater harvesting
• Swales
• Dry ponds

This links to the project page, where you can download your free copy of the LID TTT.

How to download & install the Tool

View the Step-by-step instructional video below on how to download and install the LID TTT. This video covers how to set up your model, add LIDs and analyze results for pre- to post-development scenario

How to use the Tool

View the Step-by-step instructional video below on how to use the LID TTT for you LID BMP projects.

How to size your LID using an I:P ratio

View the Step-by-step instructional video below on how to use the LID TTT to route a simple residential sub-catchment to a bioswale feature, and shows users to consider the Impervious to pervious (or I:P) ratio in sizing the LID.

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.

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.

State of the art methods or techniques used to manage the quantity and improve the quality of wet weather flow. BMPs include Source, Conveyance and End-Of-Pipe Controls.

The portion of water precipitated onto a catchment area, which then flows as surface discharge from the catchment area past a specified point.

Water from rain, snow melt, or irrigation that flows over the land surface.

The mathematical expression of the water balance.

Best management practice. State of the art methods or techniques used to manage the quantity and improve the quality of wet weather flow. BMPs include: source, conveyance and end-of-pipe controls.

The land draining to a single reference point (usually a structural BMP); similar to a subwatershed, but on a smaller scale.

A hard surface area (e.g., road, parking area or rooftop) that prevents or retards the infiltration of water into the soil.