Low Impact Development Explained
Low impact development, often shortened to LID, uses site design and distributed practices to manage stormwater closer to where rain falls.
Key points
- LID may include minimizing impervious cover, preserving vegetation, disconnecting runoff, and using small-scale controls throughout a site.
- Common practices include rain gardens, bioswales, permeable pavement, green roofs, infiltration systems, and soil restoration.
- LID works best when integrated early into site planning rather than added as decoration at the end.
- It still needs engineering, maintenance, overflow planning, and local design review.
The basic idea
Instead of treating stormwater as a waste product to pipe away immediately, LID tries to keep the developed site closer to its natural water balance where possible. That can mean reducing runoff volume, slowing flow, filtering pollutants, and spreading controls across a site.
Design before decoration
A rain garden placed after a site is fully designed may have limited effect. LID is strongest when roads, lots, buildings, parking, grading, open space, soil protection, and drainage are planned together. The goal is functional stormwater performance, not only attractive landscaping.
Long-term performance
Distributed controls can be effective, but they create many small assets that must be maintained. A community or property owner needs to know where they are, what they do, who owns them, how they are inspected, and what happens if they fail or are removed.
Questions to ask when reviewing low impact development
A useful review starts with the basics: where does the water come from, where does it go, who owns the asset, what storm was the system designed for, how is overflow handled, and what maintenance has actually been completed? These questions help separate a visible symptom from the underlying drainage problem.
For public assets, the responsible municipality, utility, road authority, conservation body, environmental regulator, or property owner may each have different roles. For private sites, design professionals and local authorities should be consulted before changing drainage, filling ditches, modifying outlets, or redirecting runoff.
Common misunderstanding
The biggest misunderstanding is assuming that stormwater infrastructure is either working or failing in a simple way. In reality, many systems work for frequent storms, struggle during larger storms, and depend heavily on maintenance, upstream land use, downstream water levels, and safe overflow paths. A problem seen at one location may be caused somewhere else in the drainage area.