Low Impact Development Planning (LID) is an innovative urban planning method that aims to imitate the natural infusion of water into the ground. It involves creating infrastructure that facilitate water to infiltrate, evaporate, and transpire while limiting runoff.
Basically, LID involves innovative stormwater technologies that allow water infiltrate the ground and evapotranspire into the air.
In the LID approach, green or living infrastructure features predominantly and also includes permeable pavements and engineered soils. Toronto, New York, and Canberra (Australia) are the few cities that have started adopting this approach.
The Convesation reports:
“In North America, urban communities built before 1980 often were not designed with any neighborhood stormwater management. Since 1980, the traditional approach to stormwater management has been an end-of-pipe system. End-of-pipe systems use centralized infrastructure located at the end of a sewer line to provide flood control and pollution management. In North America, the most popular end-of-pipe approach has been stormwater management ponds that provide temporary storage for stormwater and improve water quality through sedimentation. When these systems fail or are overloaded, residents experience flooding, and polluted stormwater is released downstream. Changing climate demands new stormwater infrastructure.
Decentralizing stormwater infrastructure creates the opportunity to build resilience and redundancy into urban planning and design, helping communities better prepare for extreme weather events, such as droughts or deluges. Integrating stormwater management throughout a neighborhood – through the use of green roofs, rainwater harvesting, infiltration systems and so on – in combination with traditional conveyance and end-of-pipe infrastructure, allows communities to simultaneously manage stormwater for both everyday and extreme events.
Cities must implement stormwater practices that are climate-appropriate. In the southwestern US, this is occurring through the proliferation of rainwater-harvesting and water-recycling infrastructure. San Diego’s pure water program is aiming to produce one-third of the city’s drinking water supply locally through water recycling by 2035. Space-limited cities such as Chicago and Toronto are experiencing green roof construction booms, which has reduced runoff. In coastal regions, we see an increase in natural infrastructure including wetlands and sand dunes.
Low Impact Development is about customizing technology to address the unique needs of a city. A well-planned community combines small, medium and large infrastructure. By sustaining naturalized water processes within urban environments, we can reduce the impact of the built environment on our water resources. Ultimately, LID combined with green infrastructure will protect citizens during extreme weather events and support healthy urban rivers and lakes.”
As more and more cities turn to green stormwater infrastructure technology, it will be interesting the measure the impact it has on both supply and resiliency.
It is important to note that some LID infrastructure have higher long term operations and maintenance costs, and if this infrastructure is being planned, this needs to be accounted for in your asset lifecycle management planning, and related expenditure projections.
PHOTO CREDIT: The image was grabbed from “NYC Green Infrastructure” video.