Spiro Agnew squirmed in his chair as he listened to consultants in April 1964 describe their plan for preserving the mostly rural valleys of northern Baltimore County. They had been hired by a wealthy group of landholders to develop the strategy, and Agnew, then the head of Baltimore County government, didn’t mask his impatience with their exquisite maps and data projections.

“Gentlemen, don’t go any further,” Agnew halted the consultants, recalled Bill Roberts, one of them. “I’ve had enough.  If I honored this, everyone with a T-square and a pencil would be doing the county plan for us.”

But if Agnew coldly received what became known as the Plan for the Valleys, he didn’t block continued discussions by county officials with Roberts and his partners Ian McHarg, David Wallace and Thomas Todd.

Agnew became governor of Maryland two years later and vice president under Richard Nixon two years after that. And the plan that irritated him initially went on to become a seminal work in environmental planning. It shaped not only growth in the county that surrounds Baltimore, but influenced generations of planners whose studies typically required McHarg’s acclaimed book “Design with Nature,” which described the valleys plan.

Even in the Baltimore area, the plan is still virtually unknown compared with other projects that same firm helped shape such as the Inner Harbor and the Camden Yards sports complex. But it will receive overdue accolades on Monday (April 12) in New Orleans when the American Planning Association recognizes it with a National Planning Landmark Award.

“I don’t know of any other instance where the private sector took the initiative for such a large area and having it based so literally on environmental factors,” said Roberts, who retired after 40 years as a principal with WRT, the firm that evolved from the original Wallace-McHarg Associates.  A half-century ago, environmental planning was already underway in communities from Hawaii to Maine, but not in an area under great suburban pressure from a major city, Roberts said.

Property owners in the hunt country of northwest Baltimore County had commissioned the Plan for the Valleys in 1963 because they feared further development eating into the Green Spring, Worthington and Caves valleys where they lived. Although many of the residents were well-connected to the political and institutional establishment of the Baltimore area, they felt they needed the heft of a professional consultant – in this instance, with an Ivy League pedigree – to make their case.

To read the plan is to grasp how difficult it is to project several years ahead, much less several decades. The authors couldn’t foresee the race riots years later that would fuel the suburban exodus nor accurately predict market forces. They projected a boom of single-family homes for “less than $20,000” by 1980.

One recent spring day, Arnold F. (Pat) Keller III, director of the Baltimore County Office of Planning, unfurled a large map of his county across a conference table in Towson.  The green crab-like form of Baltimore County looked as if someone had smeared yellow and orange paint across it. “This is what they were reacting to,” he says. “They said, ‘Holy crap, do you see what’s happening here?”

The map was the official 1960 vision for the county, based on the out-migration that had been occurring since the end of World War II. County officials envisioned many things that never came to pass: a second upper bay bridge, a second shipping port, a second “outer” Beltway and enough housing to accommodate 10,000 new residents a year – all those orange and yellow splotches on the map. In fact, that 1960 population projection for 20 years later has barely been reached yet, with about 785,000 residents in the county today.

The potential at the time, however, seemed real and menacing, especially to about 250 property owners with the means to slow things down.  Peter Fenwick, current president of the Valleys Planning Council, said the organization’s founders particularly feared plans by James Rouse to option 100 acres – an irony given that Rouse later became widely admired as the progressive, visionary developer of Baltimore’s Inner Harbor, Boston’s Faneuil Hall, New York’s South Street Seaport and the planned “new town” of Columbia, Md. Other merits of their argument notwithstanding, the most unassailable point for safeguarding the valleys was that they sit atop limestone aquifers that feed the source of clean drinking water for the residents of Baltimore.

A diary that the plan’s authors kept during their work offers a fascinating window into various obstacles. The consultants wanted stronger language than their clients to oppose racial discrimination in housing. McHarg had envisioned “hamlets” along the ridge tops above the valleys to accommodate future growth, but the clients wanted none. And after a year, some clients were chafing that the plan wasn’t spurring legislative change fast enough. They wanted more for their $125,000 investment — equivalent to $875,000 today — than “a pretty, little green book.”

“Within county government, there were folks who said, ‘It’s just rich people trying to protect their backyard’ and some of that was true, but there was also a legitimate concern about preserving the integrity of a very beautiful area that was an asset to the county and the state,” said Jack Dillon. He witnessed the argument from both sides as a county planner during the 1970s and ’80s and as executive director of the Valleys Planning Council from 1996 to 2004.

By the mid-1970s, the plan’s vision influenced county leadership to greatly constrict development potential across roughly 90 square miles. Zoning went from one house per one acre to a series of “resource conservation” areas that ranged from one house per 1 1/2 acres to one house per 50 acres.

“The actual change generated by the plan was the changing of public opinion and the desire to do something different. The plan generated a course correction,” said Keller, who’s been with the county planning department since 1988.

Officials also drew a hard boundary across the top third of Baltimore County beyond which public water and sewer would be forbidden. The so-called URDL, for Urban-Rural Demarcation Line, also became a model for planning nationwide. When you drive north on Interstate 83 from Baltimore, the interchanges in the last dozen or so miles before the Pennsylvania border don’t beckon with the neon of commerce, in fact not a single fast-food stop or gas station. The URDL is why.

But the uncommon darkness along the interstate just north of the Baltimore suburbs is matched by the luminance of the prose that begins the Plan for the Valleys. The plan itself is 62 pages, with an olive cover, a few black and white photographs and simple sketches. It’s a technical document, not a marketing one. McHarg’s introductory preamble to the report is anything but drab, however.

“The American dream has been substantially achieved. Banishment of hunger, control of disease, increased freedom, widened opportunity, accumulation and distribution of wealth, are testimonies to the American way and its success. Yet the dream of life, liberty and the pursuit of happiness do not yet have a physical expression, unless perhaps a nightmare. … Today, careless building in city and suburb destroys natural beauty. Too often, tawdriness, discontinuity, disorder and even anarchy are the result. Nature is destroyed, the image of man in the artifice of city and suburb is tragically distant from the dream. The image of happiness eludes.”

Baltimore County’s valleys remain largely unchanged from when McHarg wrote that. Keller, the county planning director, and others acknowledge that the plan didn’t have to power to stop unbridled growth — it leapfrogged to places like southern Pennsylvania and Harford County. But it did protect a fragile area that otherwise would probably be indistinguishable today.

The plan gained some national press initially, including in Fortune and Landscape Architecture magazines.  But the highest praise came from Lewis Mumford, one of the 20th century’s preeminent architectural critics and technology essayists. Mumford described the Plan for the Valleys as the most important contribution to regional planning in America since the 1920s.

Mumford wrote, “Before we convert our rocks and rills and templed hills into one spreading mass of low grade urban tissue under the delusion that because we accomplish this degradation with the aid of bulldozers, atomic piles and electronic computer we are advancing civilization, we might ask what all this implies in terms of the historic nature of man.”

(Illustrations credit: WRT, Valleys Planning Council, Baltimore County Office of Planning)