What is Low Impact Development?
Low Impact Development (LID) is an ecologically friendly approach to site development and stormwater management that aims to mitigate development impacts to land, water, and air. The LID approach emphasizes the integration of site design and planning techniques that conserve natural systems and hydrologic functions on a site. The practice has been successfully integrated into many municipal development codes and storm water management ordinances throughout the United States. Specifically, LID aims to:
Preserve open space and minimize land disturbance
Protect natural systems and processes (drainage ways, vegetation, soils, sensitive areas)
Reexamine the use and sizing of traditional site infrastructure (lots, streets, curbs, gutters, sidewalks) and customize site design to each site
Incorporate natural site elements (wetlands, stream corridors, mature forests) as design elements
Decentralize and manage stormwater at its source
Utilizing LID techniques can offer many benefits to a variety of stakeholders:
Protect regional flora and fauna
Balance growth needs with environmental protection
Reduce municipal infrastructure and utility maintenance costs
Increase collaborative public/private partnerships
Reduce land clearing and grading costs
Potentially reduce infrastructure costs (streets, curbs, gutters, sidewalks)
Reduce stormwater management costs
Potentially reduce impact fees and increase lot yields
Increase lot and community maketability
Preserve integrity of ecological and biological systems
Protect site and regional water quality by reducing sediment, nutrient, and toxic loads to water bodies
Reduce impacts to local terrestrial and aquatic plants and animals
Preserve trees and natural vegetation
Structural Low Impact Development Practices
Planners select structural LID practices for an individual site in consideration of the site's land use, hydrology, soil type, climate, and rainfall patterns. Frequently-used practices include:
Stormwater wetlands can be used to treat large areas and are often selected as a stormwater management practice because of their ability to remove excess nutrients and suspended solids from stormwater runoff. Stormwater wetlands provide similar habitat to natural wetlands. Wetlands are home to a variety insects and amphibians, many of which feed on mosquitoes and mosquito larvae.
Raingardens are an ideal method of treating stormwater on-site in urbanized settings. Raingardens are depressions in the ground that consist of loose, deep soils and are planted with colorful native vegetation.
Unlike traditional pavement, permeable pavement allows rainwater to move vertically, down through the parking surface and into the underlying soils.
Bioswales are landscape elements designed to remove pollution from surface runoff water. The bioswale filters sheet flow from the porous pavement system during excessive rainfall events and also provide a snow storage area with treatment capacity.
Rain barrels are water tanks which are used to collect and store rain water runoff, typically from rooftops via rain gutters. Storing this water reduces stormwater runoff, and also provides a free source of water that can be used for watering gardens, washing cars, flushing toilets, and doing laundry.
- Mountaintop Better Site Design Roundtable
- GCSWCD stormwater retrofit projects utilizing LID techniques
Online Seminars, Training, and Webcasts on Stormwater and LID
- EPA Watershed Academy- free online courses and information on watershed management
- EPA National Pollution Discharge Elimination System (NPDES) Training Courses and Workshops
- Using Stimulus Funds to Finance Green Water Projects
Additional Resources on Stormwater and LID
- Building Regulations Info Sheet
- DEC Stormwater Construction Permit Regulations
- Low Impact Development Center
- Stormwater Managers Resource Center
- Promoting Low Impact Development in Your Community
- Nonpoint Education for Municipal Officials: Driveways
- Managing Wet Weather with Green Infrastructure (877 Kb pdf)
- Low-Impact Development Design Strategies (8.6 Mb pdf)
- NYS DEC Better Site Design (2.2 Mb pdf)
- Massachusetts Low Impact Development Toolkit
- Better Site Design: A Handbook for Changing Development Rules in Your Community (10 Mb pdf)
- Addressing Imperviousness In Plans, Site Design and Land Use Regulations