Engineering hub

Low Impact Development's most powerful concepts are in the drainage planning of the entire site, at any scale.

• Reject dated ideas of concentrating all of the stormwater together in one corner.
• Argue against levelling every site into a generic, difficult to drain flatness.

When water is permitted to flow in a greater number of directions, each structural practice or BMP becomes much more efficient and cost effective. Ideas for contemporary site planning strategies can be found in:

• Existing hydrology
• Natural drainage

LID BMPs are like a toolbox from which engineers can pick and choose depending on site constraints. But this has to come after a larger scale planning strategy to manage water and other ecosystem spaces.

Selection of suite of LIDs: the Treatment Train Tool

LID Treatment Train Tool

In order to assess if the selected suite of BMPs effectively meet the design criteria, use either computer models or simple spreadsheet models. Base Mmdel selection on the size and type of development. A wide range of simple to complex computer models such as Visual OTTHYMO, SWMM, SWMMHYNO, HSP-F and QUALHYMO are available. See Modeling.

STEP have developed the Low Impact Development Treatment Train Tool to help developers, consultants, municipalities and landowners understand and implement sustainable stormwater management planning and design practices.

Mathematical notation used throughout the site.

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.

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.

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.

A biological community, including humans and their natural environment.

Sustainable Technologies Evaluation Program