What Is Green Infrastructure?

W ebster's New World Dictionary defines infrastructure as “the substructure or underlying foundation, especially the basic installations and facilities on which the continuance and growth of a community depends.” When they hear the term infrastructure, most people think of roads, sewers, utility lines, and other gray infrastructure; or hospitals, schools, prisons, and other social infrastructure . Taken together, these types of facilities are often referred to as built infrastructure . If infrastructure is what society counts on to provide essential services, why should the green stuff – trees that scrub the air and sequester carbon dioxide, streams that filter runoff, fields that produce food-be mentioned in the same breath as the gray stuff. With the potential of global warming, green infrastructure is not an amenity; it's a necessity.

Green infrastructure may be a relatively new term, but it's not a novel concept. Park Planner Fredrick law Olmstead designed networks of connected parks over 100 years ago. And wildlife biologists have long known that linking parks and preserves with natural corridors is the best way to protect native plants and animals. As far back as the 1990's green infrastructure emerged as part of Florida 's Statewide Greenways System

At MJA Consulting we define Green infrastructure as:

An interconnected network of natural ecosystems and human influences ecosystems: greenways, parks and other conservation lands; working farms, ranches and forests; and other open spaces that support native species, maintain natural ecosystem values and functions, sustain air and water resources and provides associated benefits to human populations on which the continuance and growth of a community depends

The elements of a green infrastructure network need to be protected over the long term. This requires long-range planning and management, as well as an ongoing commitment.

What Does Green Infrastructure Look Like?

At the regional and local level green infrastructure encompasses a wide variety of natural and restored native ecosystems and landscape features that make up a system of “hubs” and “links.” At the site plan level it can include engineered systems such as green roofs, porous pavement gardens all engineered to link with the regional green infrastructure.

Supplementary or Engineered systems: These systems add to or serve as a supplement to natural ecosystem processes. An example of this is the EPA Green infrastructure program, a comprehensive plan to reduce polluted runoff and increase environmental and economic benefits for communities.

Common supplementary green infrastructure approaches include:

• Conservation Easements
• Grassed Swales
• Porous Pavements
• Green Roofs
• Infiltration Trenches
• Innovative Street Design
• Open Space design
• Rain Gardens/Bioretention
• Riparian Buffers/ Forested Buffers
• Stormwater wetlands
• Vegetated Filter Strips
• Low Impact Development
• On-Lot Treatment (e.g., rain barrels, cisterns, downspout disconnections0

Complimentary or natural systems: These systems fill out or complete the ecosystem and consist of Hubs and Links.

HUBS anchor green infrastructure networks and provide an origin or destination for wildlife and ecological processes moving to or through it. Hubs come in all shapes and sizes, including:

RESERVES — Large protected areas, such as national and state parks and wildlife refuges;

MANAGED NATIVE LANDSCAPES — Large publicly owned lands, such as national and state forests, managed for resource extraction as well as natural and recreational values;

WORKING LANDS — Private farms, forests, and ranches that are managed for commodity production yet remain in a predominantly open and undeveloped state;

REGIONAL PARKS AND PRESERVES — Less extensive hubs of regional ecological significance; and

COMMUNITY PARKS AND NATURAL AREAS — Smaller parks and other sites at the community level where natural features and ecological processes are protected and/or restored. Florida Greenways Commission

LINKS are the connections that tie the system together and enable green infrastructure networks to work. They range in size, function and ownership, including:

LANDSCAPE LINKAGES — Large protected natural areas that connect existing parks, preserves, or natural areas and provide sufficient space for native plants and animals to flourish while serving as corridors connecting ecosystems and landscapes. Landscape linkages may also provide space for the protection of historic sites and opportunities for recreational use;

CONSERVATION CORRIDORS — Less extensive linear protected areas, such as river and stream corridors that serve as biological conduits for wildlife and may provide recreational opportunities;

GREENWAYS — Protected corridors of land managed for resource conservation and/or recreational use;

GREENBELTS — Protected natural lands or working lands that serve as a framework for development while also preserving native ecosystems and/or farms or ranchland; and

ECOBELTS — Linear woody buffers that can ease the zone of tension between urban and rural land uses while providing ecological and social benefits for urban and rural residents.

On a regional basis power lines and pastures, freeways and forests connect with individual properties through green infrastructure. Parks, outdoor recreation and ecotourism opportunities are just a part of the Green Infrastructure. Beyond recreational uses, Green Infrastructure sequesters carbon, deals with stormwater runoff, cleans up air and water pollution, creates oxygen, promotes biodiversity and ensures that the environment can continue to deliver essential eco-services through strategic planning. Green Infrastructure is no longer an optional amenity, it's a necessity.