The Blue Line: How Boulder Learned to Say No

The mountain backdrop west of Boulder, the long slope rising from the city's residential streets toward the base of the Flatirons, looks undeveloped because someone decided, in nineteen fifty-nine, to keep it that way.

By the late nineteen fifties, housing was beginning to creep up the hillsides above University Hill. Landowners were willing to build. The city was growing with the university, and the mountain slopes offered attractive views and cooling breezes. A group of University of Colorado professors, including mathematician Robert McKelvey and physicist Albert Bartlett, organized a campaign to stop it.

What they proposed was remarkably simple: an amendment to the city charter prohibiting the extension of city water service above an elevation of five thousand seven hundred and fifty feet. No water service meant no reliable plumbing. No reliable plumbing meant no practical construction. Property owners could still build above the line if they provided their own water and sewer systems, but that constraint effectively preserved the mountain backdrop.

The charter amendment passed in nineteen fifty-nine and was called the Blue Line. The activists who had organized the campaign immediately recognized that the same civic infrastructure they had built could be applied to other land use problems. In the fall of that year, they formed PLAN Boulder County, the advocacy group that would, eight years later, campaign for the open space sales tax.

The Blue Line is still in effect. If you look at the slope behind this neighborhood, you are looking at a decision made sixty-seven years ago, and at what Boulder chose to forgo.