Low Impact Development (LID) is a stormwater management practice aiming to reduce runoff and pollutant loadings by managing runoff as close to its source(s) as possible. LID includes overall site design and individual small-scale stormwater management practices (isolated LID practices) that promote the use of natural systems for infiltration, evapotranspiration and the harvesting and use of rainwater.

LID and Preserving Natural Landscapes

LID should emphasize “preserving […] natural landscape features, minimizing effective imperviousness to create functional and appealing site drainage that treat stormwater as a resource rather than a waste product” through natural site hydrology rather than installation of infrastructure. This includes the preservation of intact forests, wetlands, meadows, riparian areas, and more, which can prevent the creation of stormwater runoff through rainwater absorption while also recharging and filtering groundwater supplies.  

Photo credit: Protection of Ain Sokna -Zafrana Road From Flood Hazard

While LID aims to mimic natural landscape features, it should be considered second to preservation, as there is no replacement for the ecosystem benefits that naturally formed landscapes provide.

Green Stormwater Infrastructure (GSI)

According to the EPA, Green Stormwater Infrastructure (GSI) is an integrated system of natural elements and LID practices that provide broad environmental benefits. GSI includes applied practices such as green roofs, porous pavement, swales and rain gardens (which are also LID practices) that largely rely on using soil and vegetation to infiltrate, evapotranspiration, and/or harvest stormwater runoff and reduce flows to drainage collection systems. For many, GSI is becoming an umbrella term under which other terms, such as LID, fit.

Benefits:

  • Provides more ecological benefits when compared to traditional stormwater and sewer systems
  • Mitigates flooding
  • Improves water quality
  • Improves aesthetics of a community
  • When properly implemented and maintained, may result in cost-savings

GSI shifts away from conventionally engineered drainage systems and impervious infrastructure to more natural stormwater management practices.

Here are some examples from a construction projects in the Naugatuck Valley Region:

Permeable brick pavers being installed in Derby, CT. These pavers allow water to infiltrate through the spaces between the pavers/bricks and filter into the ground below, reducing stormwater runoff and minimizing erosion.
Rain Garden adjacent to a permeable parking lot along Route 34 in Derby, CT. These are cost-efficient depressions in the landscape that typically include native plants or trees and a mulch layer or ground cover. This includes curb cuts for stormwater runoff to flow into the rain garden from the parking lot and drainage to prevent overflow.
Covered tree trenches along East Main Street, Waterbury that will absorb stormwater and allow infiltration into the soil.
Rain Garden installed at the Byam Rd. Fire Station in Cheshire, CT that allows infiltration and filtration of stormwater.

NVCOG Support Services

  • MS4 and LID Local Regulation Assessment

NVCOG staff assist municipalities in meeting MS4 permit requirements by providing regulation assessments, regulatory recommendations, and ongoing technical support. Assistance is available upon request, please contact tdougherty@nvcogct.gov.

  • Complete Streets Planning

NVCOG is committed to creating safer, more inclusive streets that serve all road users. The Complete Streets Guidebook (October 2024) offers strategies, including Green Stormwater Infrastructure and Low Impact Development interventions, to help municipalities make safer, greener streets. Please contact kellis@nvcogct.gov for more information.

  • Public Outreach and Education

NVCOG has contracted with the Pomperaug River Watershed Coalition to provide public outreach materials through the RiverSmart program. Use the links to navigate to locate materials your municipality can share and distribute. 

  • Site Plan Reviews

NVCOG transportation and environmental departments can review site plans for new development and redevelopment projects to suggest LID and GSI implementation. Please contact tdougherty@nvcogct.gov for assistance.

Additional Resources

Maine Audubon and partners have promoted their “Stream Smart” program since 2011. They host workshops and field trainings for organizations, local officials, and the public across New England. This practice reconnects stream habitat for wildlife and enhances culvert construction practices to improve infrastructure and environmental degradation.

This manual is intended for use as a planning tool and design guidance (GSI/LID) document by the regulated and regulatory communities involved in stormwater quality management.

NVCOG teamed up with members of UConn CLEAR staff to show municipalities various GSI examples and what it takes to maintain this infrastructure.

This webpage illustrates various examples of GSI, case studies throughout the state, and a rain garden certificate course for interested parties.