Why Green Infrastructure?

Green infrastructure is a term that is appearing more and more frequently in land conservation and land development discussions across the United States and the world. The term, however, means different things depending on the context in which it is used: for some it refers to trees that provide ecological benefits in urban areas; for others it refers to engineered structures (such as storm water management or water treatment facilities) that are designed to be environmentally friendly.

Our definition of green infrastructure is loftier and broader. We define it as an interconnected network of natural areas and other open spaces that conserves natural ecosystem values and functions, sustains clean air and water, and provides a wide array of benefits to people and wildlife. Used in this context, green infrastructure is the ecological framework for environmental, social, and economic health—in short, our natural life-support system.

Green infrastructure challenges popular perceptions about green-space planning and protection. To many people, open space is simply land that is not yet developed, and green space refers to isolated parks, recreation sites, or natural areas. Webster's Dictionary defines "infrastructure" as "the substructure or underlying foundation on which the continuance and growth of a community or state depends." Green infrastructure emphasizes the importance of open and green space as parts of interconnected systems that are protected and managed for the ecological benefits they provide. While green space is often viewed as something that is nice to have, green infrastructure implies something that we must have. Protecting and restoring our natural life-support system is a necessity, not an amenity. While green space is often viewed as self-sustaining, green infrastructure implies that green space and natural systems must be actively protected, managed, and in some cases restored.

Green infrastructure differs from conventional approaches to land conservation and natural resources protection because it looks at conservation in concert with land development and man-made infrastructure planning. Other conservation methods typically are undertaken in isolation from—or even in opposition to—development, but green infrastructure provides a framework for conservation and development that acknowledges the need for providing places for people to live, work, shop, and enjoy nature. Green infrastructure helps communities identify and prioritize conservation opportunities and plan development in ways that optimize the use of land to meet the needs of people and nature.

WHAT IS GREEN INFRASTRUCTURE?

Used as a noun, green infrastructure refers to an interconnected green space network (including natural areas and features, public and private conservation lands, working lands with conservation values, and other protected open spaces) that is planned and managed for its natural resource values and for the associated benefits it confers to human populations. Used as an adjective, green infrastructure describes a process that promotes a systematic and strategic approach to land conservation at the national, state, regional, and local scales, encouraging land-use planning and practices that are good for nature and for people.

Taking a green infrastructure approach provides benefits both as a concept and as a process. As a concept, the planning and management of a green infrastructure network can guide the creation of a system of open space hubs and links that support conservation and associated outdoor recreational and other human values, connect existing and future green space resources, and "fill in" gaps. As a process, the approach provides a mechanism for diverse interests to come together to identify priority lands for protection. Green infrastructure provides a framework that can be used to guide future growth and future land development and land conservation decisions to accommodate population growth and protect and preserve community assets and natural resources. Taking a green infrastructure approach facilitates systematic and strategic conservation activities, adds value to project results, and provides predictability and certainty for both conservationists and developers. In areas anticipating growth, a green infrastructure plan can pre-identify key lands for future conservation and restoration efforts and help shape the pattern and location of future growth.

Green infrastructure uses planning, design, and implementation approaches similar to those used for roads, water management systems, and other community support facilities. The approach can be applied at multiple scales (e.g., across landscapes, watersheds, regions, jurisdictions) and can help move communities beyond jurisdictional and political boundaries.

Green infrastructure also provides a strong rationale for funding green space conservation and management. Just as roads, sewer systems, hospitals, and other aspects of the built or gray infrastructure provide for the critical needs of communities, green infrastructure is integral to a community's health and viability. Like gray infrastructure, green infrastructure has evolved to meet specific needs that have resulted from growth (see Table 1.1).

The Need for a New Approach to Conservation and Development

The first European explorers who saw the New World wrote poetically about its vast wilderness. Land was plentiful; the challenge was to tame it, to make way for towns, roads, and farms. Americans today experience a far different landscape from that seen by these explorers. Wilderness and natural areas are no longer plentiful; in fact, they have become scarce. Less than 10 percent of the land in the United States remains in a wild state, and only 4 percent has been set aside in nature reserves.

While previous generations of Americans had the foresight to protect some of America's most beautiful and vital landscapes, our public lands have proven to be inadequate to meet the needs of both people and wildlife. The conditions that existed when the National Park Service and other resource agencies were founded have changed dramatically, but the assumptions that guide our land conservation decisions remain stuck in the past. The rural lands that once surrounded public lands are fast disappearing. National and state parks and wildlife refuges are becoming ecological islands in an increasingly fragmented landscape. Population growth and development in communities that serve as gateways to...