Many municipalities are dealing with growing communities that are supported by inadequate and aging stormwater infrastructure. The traditional system of concrete curbs, gutters, and pipes is referred to as gray infrastructure. Municipalities are also challenged with meeting more stringent federal, state and local regulations in place to protect human health and safety, as well as the environment.
To meet these demands, municipalities are learning to implement more sustainable stormwater management techniques that utilize nature’s capacity to reduce runoff and improve water quality. This innovative approach to stormwater management is commonly referred to as green infrastructure.
This website is not meant to be an extensive resources of all green infrastructure topics, but a tool to help municipal decision-makers choose the most effective way to implement green infrast
ructure and promote education about stormwater issues. We encourage you to explore the information on this website, and we would like to have your feedback to inform us about topics you would like to learn more.
Storm sewer outfall
Aging stormwater infrastructure
Construction of storm sewer system
Untreated sanitary sewage overflowing into creek
What is Green Infrastructure?
The green infrastructure approach is an integration of natural processes and man-made structures to control storm water management. Green infrastructure is the practice of reducing the volume of stormwater runoff that leaves an individual site by implementing structures that mimic natural landscapes by encouraging the processes of infiltration, plant uptake (transpiration), and evaporation. These processes help retain stormwater onsite as much as possible, but also slows the flow of stormwater that does leave the site.
Parking lot with bioretention
GI is often used interchangeably with Low Impact Development (LID), but both techniques employ methods that are very similar if not identical. However, LID is often used when referring to new developments, whereas green infrastructure encompasses new developments and redevelopments. GI is an alternative to conventional stormwater controls (sometimes referred to as gray infrastructure) that utilize concrete curbs, gutters, catchbasins and pipes to collect and convey stormwater from a site. The conventional practice has been to convey stormwater from a site as quickly as possible, to prevent local ponding and flooding.
Green Infrastructure emphasizes a different approach. GI techniques attempt to mimic a site’s predevelopment hydrology by using distributed landscape features and engineered devices such as bioretention, grass swales, vegetated rooftops, rain barrels, and permeable pavements to reduce runoff, reduce pollutant discharges, decrease erosion, and maintain base flows of receiving streams.
Green infrastructure is the practice of capturing and infiltrating rainwater at the site of origin, before it accumulates, collects pollutants and leaves the site where it may discharge to the local stream. Plants are used for their ability to uptake water from soil in a process called transpiration. Transpiration draws water to the green surface of the plant where it can evaporate to the atmosphere.
In comparison to conventional gray infrastructure, green infrastructure has a greater capacity to reduce the volume of stormwater before it has a chance to leave a site. Green infrastructure also enhances the ability of microorganisms to breakdown the chemical constituents associated with stormwater pollution. The additional benefit of GI is that it can be implemented in a manner that is less expensive than conventional stormwater collection and conveyance systems.
This website has been designed to provide information and resources that will help make an informed decision to use green infrastructure for stormwater management. We have also included several examples of green infrastructure that have been implemented in Kentucky. We hope to regularly update this site with new examples of green infrastructure in Kentucky and information to help municipal decision-makers.