Urban Growth Boundaries
The metropolitan Portland urban growth boundary (in red).
Image by Michele Dailey.
Without clearly defined and legally enforceable boundaries, towns and cities inevitably sprawl into the countryside, impairing land with agricultural, ecological, and historical significance.
An Urban Growth Boundary (UGB) is a zoning tool that maintains a relatively high density of housing and commercial development inside the boundary and a rural density outside the boundary. Ecologically and culturally sensitive areas inside the UGB should be set aside, and a mix of residential, commercial, and green industrial uses permitted. This encourages the formation of compact towns and cities, with all the advantages for transit, infrastructure, and human-scale neighborhoods they offer. At the same time, it removes development pressures from farms, forests, and wildlands located outside the boundary, helping to preserve productive rural areas and ultimately contributing to a broader matrix of connected wildlands.
UGBs can be implemented through (reversible) zoning laws or (irreversible) land purchases and conservation easements. Oregon's land-use planning laws, administered through the Department of Land Conservation and Development, require each town and city in Oregon to maintain a 20-year supply of residential, commercial, and industrial lands inside their UGBs. This ensures an orderly development pattern, working from the core out. Lands outside the boundary receive rural zoning types. However, these boundaries can be periodically extended outward in response to growth pressures, potentially reversing rural zoning in areas adjacent to existing UGBs.
Outright land purchases and conservation easements can maintain de facto UGBs by protecting continuous greenbelts and corridors or maintaining rural reserves with lands of special agricultural, ecological, or cultural significance. When comprehensive enough, such land purchases and easements provide effective barriers to new development. Conservation easements permanently remove certain development rights from parcels of land, allowing owners to stay on their land while decreasing their property tax. These strategies, unlike zoning laws, result in permanent land protection, but at great cost. Zoning laws have the virtue of being implemented at very little cost through popular vote, but have the corresponding vulnerability of being overturned in the next vote.
Ideally, an urban growth boundary creates a strong transition between urban and rural areas. The boundary itself should be a place of great beauty and integrity, forming a strong gateway inviting one both inward to the city and outward to rural areas and the wilderness beyond.
Create, either through zoning laws or land purchases and easements, an effective boundary around every city and town to channel residential and commercial development. Maintain a working rural landscape up to the edge of the city, providing additional protection as needed for land of special significance. Make the boundary itself a beautiful gateway to the city for rural dwellers and to the countryside for city dwellers.
Case Studies
Examples of this pattern in action:
Portland Metropolitan Area
We can all see the effects of rapid growth on our highways, housing, shopping and open spaces. But growth doesn't have to just happen. The Growth Management Services Department provides planning services and land-use information to local governments, policy makers and citizens of the region so that we can maintain our livability while planning for the next 50 years of growth.
Is The American Dream Endless Sprawl?
This is a speech given by Robert Liberty, Executive Director of 1000 Friends of Oregon regarding the detriments of urban sprawl and the benefits of smart growth.
Organizations whose work incorporate this pattern:
Milpitas Urban Growth Boundary Project
References:
American Planning Association. Staying Inside the Lines: Urban Growth Boundaries. American Planning Association. Chicago, IL. 1997.
Greenbelt Alliance. Urban Growth Boundaries Information Packet. Urban Growth Boundaries. San Francisco, CA.
