Low impact development, or LID, is a method of developing the land that minimizes the disruption of natural water flow. It’s a method of stormwater management that allows developed land to work as naturally with Mother Nature as possible.
In case you’re in charge of developing a plot of land and you want it to be as eco-friendly as possible, let’s take a look at 6 LID strategies you can utilize:
The Basic Goal of LID Strategies
Environmental concerns, the heat island effect in urban areas, and water pollution have all prompted the increased use of LID when developing new land. The main goal of LID is to implement source control over stormwater, which means, instead of directing all stormwater and runoff into a sewer or single pipeline for a city to deal with, the stormwater is dispersed and directed back into the ground at the source. This keeps water tables replenished and prevents storm systems from becoming overloaded.
There are 3 levels to LID strategies. They are distribution, hardscape material and curb replacement, and recycling runoff and rainwater.
Distribution is typically achieved by using open areas of vegetation intended to allow stormwater to soak directly into the ground. This includes sustainable and native plants, tree box filters, bioswales, structural soil, bioretention cells, and soil amendments.
Level 2 LID strategies replace impermeable materials with permeable materials wherever feasible. This includes parking lots, alleyways, and sidewalks. This is accomplished by implementing permeable materials like porous concrete and, for maximum efficiency, gravel or grass-filled plastic grid permeable pavement. Roads are sloped towards these permeable areas and curbless parking lot islands are used to allow for the easiest flow of stormwater into these areas.
Level 3 LID strategies are used to recycle runoff and rainwater from roofs, sidewalks, and roads. It is then directed to subsurface facilities where it’s treated and reused for non-potable purposes. Some tools for implementing this strategy include disconnected roof drains, retention facilities below parking lots, cisterns, rain barrels, and rooftop channels.
6 Effective LID Strategies
1. Green Roofs
With a focus on commercial properties, green roofs are an effective way to filter and retain stormwater. They use entire roofs filled with greenery, like plants and shrubs that help absorb rainfall as well as slow the flow into storm systems. This method is considered a level 1 LID strategy.
2. Shrubs and Trees
They are not very effective on a residential or individual scale, but using trees and shrubs on commercial properties can act as a vertical rain garden. Trees help capture runoff and rainwater and can be a very effective strategy or even just a nice supplementive boost to LID efforts when planted correctly. This is another example of a level 1 LID strategy.