Controlling Sprawl in Boulder

Benefits and Pitfalls
Peter Pollock, Janeiro 1, 1998

Boulder, Colorado, has developed a national reputation for having dealt creatively with growth management issues. The city has developed a 27,000-acre greenbelt, a system for controlling the rate of population growth by limiting building permits, and a defined urban growth boundary managed in cooperation with Boulder County. Boulder’s approach to urban growth boundaries, called the service area concept, offers important lessons for controlling sprawl, preserving rural land uses outside the city, and extending urban services in a rational manner.

Located 27 miles northwest of Denver at the base of the Rocky Mountains, Boulder is a home-rule city of approximately 96,000 people. It is the Boulder County seat, the home of the University of Colorado, and a regional employment center with approximately 86,000 jobs. Its strong economy is founded on the university, federal laboratories, regional and local retail, and a dynamic industrial sector concentrated in the high tech industry and business services.

Colorado has no statewide, mandated planning program. Statutory and home-rule cities and counties are granted land use planning and regulatory powers directly by the state. The Denver Regional Council of Governments engages in general planning, clearinghouse, and federal funding allocation activities, but there is no real, effective regional planning effort. As a result, sprawling development, undifferentiated between cities and unincorporated areas of counties, is typical along most of Colorado’s Front Range.

In the decade of the 1950s, Boulder’s population grew from 25,000 to 37,000 and during the 1960s it grew by a whopping 29,000 to reach 66,000. Some initial efforts to manage this growth included the “Blue Line,” a citizen-initiated amendment to Boulder’s charter in 1959 that restricted the extension of city water service above an elevation of 5,750 feet. It was later extended by ordinance to sewer service. While a few exceptions have been granted at the ballot box, the effect of this measure was to limit the city from extending water service to properties along the mountain backdrop. Property owners can still develop in the county, but at much lower densities than is typical in the city and only with individual water and septic systems.

Another important growth management program began in 1967, when Boulder became the first city in the United States to pass a tax specifically dedicated to preserve open space. This open space system forms the outer extent of the Boulder Valley, a joint planning area between the city and county.

Boulder’s Service Area Concept

A concern that unwanted development was continuing to take place outside city limits in the county, sometimes with city water and sewer service, led to the implementation of Boulder’s urban growth boundary. In 1970 the city and county adopted a joint comprehensive plan that defined the intended geographic extent of city expansion into the plains. This plan was further refined in 1978 to limit the city from extending water and sewer services outside city service area boundaries and to limit the county from approving new subdivisions that would need “urban” levels of services and facilities.

What specifically does the service area boundary do? It defines that part of the Boulder Valley planning area where the City of Boulder either already provides a full range of urban services to annexed properties or will provide services upon annexation. Land outside the service area boundary remains in the county at rural densities until the city and county jointly agree to bring the property into the service area. Land can also be “moved” out of the service area.

The 1978 plan, thus, protected the city against development just outside its boundaries that would put demands on city services without the ability to collect taxes to finance those services. It was also aimed at controlling sprawl, protecting sensitive environmental areas and rural land uses, and planning, financing and providing urban services in a more rational way. By adopting the plan through an intergovernmental agreement, both the city and county gained better control over urban development and service provision, while accomplishing many other conservation objectives. This approach owes much to the phased growth control ordinance pioneered in 1969 by the Township of Ramapo, New York.

What Are the Benefits?

  • The service area concept creates an identifiable urban/rural edge. Unlike many cities that have either sprawled into the countryside or facilitated leapfrog development, Boulder has created a real edge between urban and rural development.
  • It provides for the rational extension of urban services. The definition of areas where services are to be provided (along with initial designations of land use) allows a direct link between land use planning and infrastructure planning. Parks, recreation, police, fire, transportation, water, sewer and flood control service providers can develop their master plans knowing where services are to be extended, over what time frame, and for what types of land uses.
  • It helps preserve rural lands outside the city. Boulder’s service area policy has sent a clear signal to the land markets that land outside of Boulder’s service area is not likely to be urbanized in the near future. This has lessened land speculation for urban development purposes and facilitated the acquisition of open space.
  • It helps focus development within the city. Through redevelopment of underutilized areas and infill development, the city has been able to capitalize on existing public investments in infrastructure.
  • It eliminates competition from the county for retail development and the loss of associated tax revenues.
  • It provides both flexibility and certainty to the planning process. As the community experiences change over time, land can be added to or deleted from the service area, and property owners inside and outside the service area can act accordingly.

What Are the Pitfalls?

  • Boulder’s region encompasses the whole county. Therefore, the city’s surging job growth and limitations on residential growth have had a significant impact on housing demand in adjoining communities. The most striking example is the nearby town of Superior. In 1990 the population of Superior was 255; in 1996 it was 3,377. It has practically no jobs and no sales tax base. This regional imbalance between jobs and housing has created tremendous problems with traffic congestion, lack of affordable housing and school facility needs.
  • Getting a hold on sprawl is only half the equation. What happens within the urban service area is the other. In Boulder’s initial planning efforts, there was a clear expression of a preference for infill and redevelopment over sprawl. Since there is no requirement that a certain amount of land be contained within its service area (such as the 20-year required land supply within Oregon’s urban growth boundaries), Boulder does not have to make a trade-off between expansion versus infill and redevelopment. However, it is increasingly difficult to convince specific neighborhoods and the community as a whole that additional density is in their best interests. The community can choose to not expand the service area, maintain current densities and simply not grow.

Is that good or bad? On the good side, it has allowed Boulder to determine its own ideal city size, with consideration of how much congestion is tolerable, what sized city leads to a high quality of life, and what is sustainable over time. On the bad size, it holds Boulder back from capturing some of the benefits that additional development could bring, such as more affordable housing and less dependence on the automobile by building mixed use, transit-oriented neighborhood centers.

There is no real ending to this story. Land use planning is a major fixation for Boulder, and these issues are continuously analyzed, discussed, and often hotly debated. Nevertheless, Boulder has maintained a central vision of a compact city with a clear identity in the midst of a rural area. The growth management techniques used in Boulder may vary from those used by other cities, and they may be changed from time to time to meet local conditions, but the vision has remained intact.


Peter Pollock, AICP, is the director of the Community Planning Division for the City of Boulder, Colorado. This year he is a Loeb Fellow at the Harvard University Graduate School of Design and a visiting fellow at the Lincoln Institute. This article is based in part on his presentation of the Fourth Annual David R. Fullmer Lecture, “Tools and Techniques for Managing Growth in the Boulder Region,” at the Institute in October 1997.