The concept of green infrastructure is about creating infrastructure that mimics, restores or maintains natural hydrology. Green infrastructure includes a wide array of practices at multiple scales that manage wet weather and that maintains or restores natural hydrology by infiltrating, evapotranspiring, or harvesting and using stormwater. On a regional scale, green infrastructure is the preservation or restoration of natural landscape features, such as forests, floodplains and wetlands, coupled with policies such as infill and redevelopment that reduce overall imperviousness in a watershed. On the local scale, green infrastructure consists of site and neighborhood-specific practices, such as bioretention, trees, green roofs, permeable pavements and cisterns
In other words, the idea is to improve and maintain water quality by using less concrete / pipes and more native landscaping to achieve good water quality. There is a certain natural aesthetic tied into the concept of green infrastructure. A turf covered depression may function close to the same as a rain garden. But the natural aesthetic of the garden with native plants makes the rain garden infrastructure more closely mimic the natural (pre-development) hydrology. As will be detailed in the articles below beyond the benefits of infiltrating stormwater runoff in a rain garden there are other benefits to a rain garden being a garden.
Water is continually on the move on, above and below the surface of the earth. This movement is called the water cycle (AKA: hydrological cycle or H2O cycle). The water moves by the physical processes of evaporation, condensation, precipitation, infiltration, surface runoff, and subsurface flow. In doing so, the water goes through different phases: liquid, solid (ice) and vapor. To talk about the water cycle is to talk about:
The total amount of water on earth is considered to have been more or less constant for hundreds of millions of years. What is not constant is the amount of water that is liquid, gas or solid that is below, on or above the surface at a particular location. Again in plain language less ice means more liquid water (higher sea levels) and / or more humidity. Pumping out groundwater means more surface water and / or more humidity. There are many scenarios which would illustrate how the balance in the water cycle changes yet the total amount of water on earth does not change.
Water is requirement for all known living organisms. The trick is to the water supporting life is the water has to be of a certain range quality. Fish needs some oxygen to be dissolved in the water to survive. Thousands of species of fish live in the saline oceans but humans cannot survive drinking ocean water because of the saline. Water quality is about the concentration of what is suspended or dissolved in the water. When we talk about water quality it is relative to ability to support various uses of the water. Water is an excellent solvent. The list of things that will dissolve in water is very long. Even many things that don't dissolve in water will suspend in water.
In the past several centuries, man has changed the natural hydrology by adding infrastructure. For example:
The result of these activities has adversely affected the water quality and changed the hydrologic balance. The goal of Green infrastructure is to move back to a more natural hydrology while supporting the needs of our civilized world.
This portal has links to numerous articles relating to various aspects of using natural hydraulic methods to preserve and restore good water quality. In other words, this portal is about providing information about the use of green infrastructure.
Conceptually Green Infrastructure is about using natural hydrology and topography to benefit water quality. The articles below should help provide a base of high level information which is in turn linked to more detailed technical information to assist in creating "Green Infrastructure".
'Definition of GI:' this is what’s in the manual now:
green infrastructure -means a wide array of practices at multiple scales that manage wet weather and that maintains or restores natural hydrology by infiltrating, evapotranspiring, or harvesting and using stormwater. On a regional scale, green infrastructure is the preservation or restoration of natural landscape features, such as forests, floodplains and wetlands, coupled with policies such as infill and redevelopment that reduce overall imperviousness in a watershed. On the local scale, green infrastructure consists of site and and neighborhood-specific practices, such as bioretention, trees, green roofs, permeable pavements and cisterns
Notice all the green call-out boxes for green infrastructure.
'GI BMP’s: '
'GI and Climate Change/Adaptation/Resiliency'
The MPCA’s Stormwater Program has been addressing the issues related to climate change adaptation since 2005 with the first issuance of the Minnesota Stormwater Manual. It advanced the concept of treating water on site, using low impact design, and volume control best management practices (BMPs). Since then, stormwater permits have advanced these BMPs, and MPCA has worked to set goals and quantify credits for using these BMPs through the Minimal Impact Design Standards (MIDS) Project. Consistent with MIDS are BMPs that can increase infiltration and reduce runoff (including green infrastructure like rain gardens, urban forestry/trees, pervious pavement, swales, etc.) Local units of government have traditionally worked to get water off the landscape as quickly as possible. In the last couple of decades, the MPCA has started addressing pollutant and rate control. We are now beginning to address volume control. Volume control, and working to mimic natural hydrology, helps to result in less dramatic runoff events, which reduces stream erosion and scouring. Impervious surfaces are increasing faster than population growth. This increase in impervious surface coupled with larger storm events will have a significant impact on receiving waters. Stormwater capture and reuse is an opportunity to reduce runoff and reap benefits from heavier rainfalls while reducing demands on the potable water supply.
NOAA Atlas 14 updates are being utilized to more accurately reflect precipitation intensities and durations. NOAA Atlas 14 incorporates 50 additional years of data into the estimate of precipitation 27 intensity and durations, and could account for changes that may be related to climate change. These estimates, used as an engineering standard, are vital to ensure proper design of culverts, storm sewers, and water quality devices.
In August 2013, the reissued Municipal Separate Storm Sewer System (MS4) General Permit became effective, which regulates stormwater discharge from counties, cities, townships and other publicly owned entities in urbanized areas. The goal of the MS4 program is to prevent or reduce the discharge of pollutants to stormwater, and ultimately, surface waters. This permit’s provisions will help to address problems of erosion and water pollution associated with heavy precipitation events.
'GI and health benefits:'
'GI and sustainable communities:' EPA: Enhancing Communities with Green Infrastructure: https://www.epa.gov/smartgrowth/enhancing-sustainable-communities-green-infrastructure
'For municipalities: '
Integrating GI : EPA: GI Opportunities that Arise During Municipal Operations: https://www.epa.gov/sites/production/files/2015-09/documents/green_infrastructure_roadshow.pdf Meet permit requirements with GI:
GI and brownfield development:
'Link to other reports:' EQB