Food substitution is among the household arts that make daily living possible. One cup of buttermilk, for example, can be substituted with a tablespoon of lemon juice or vinegar plus enough whole milk to make one cup. Or two cups of tomato sauce can be replaced with three-quarters cup of tomato paste, plus one cup of water. A few substitutions do not spoil the dish. They may even improve the taste.
At a certain point, however, the cook can substitute no further, or the dish will be spoiled. At very least, the dish will end up very differently from the one the cook originally set out to make.
It is a matter of opinion whether downtown Pleasant Hill is a dish that has been spoiled. What is indisputable is that the final product, from a site-planning perspective, looks very different than the original site plan.
One might ask why we should care. This five-block area in little Pleasant Hill a city 30 miles east of San Francisco with a population of 32,000 accomplishes most of its original aims: The city now has a readily identifiable center, and provides a walkable downtown area where one did not exist before.
Still, something is troubling here. The final, built version of downtown Pleasant Hill has lost much of the coherence, and possibly the charm, that was promised in the original site plan. A clear arrangement of streets and open spaces has been replaced by something that looks very much like a conventional power center.
The story of downtown Pleasant Hill, in short, is an object lesson in the depredations that developers can inflict on urban design if not constrained by firm guidelines. The experience of the Bay Area city might provide an argument against the time-honored practice of cities relying wholly on retail developers to design pedestrian-oriented downtowns.
If not a masterpiece, the original site plan of downtown Pleasant Hill designed, in succession, by Heller Leake and Field Paoli was intriguing. Much, perhaps too much, was going on in this plan. It incorporated in a very small area some of the fanciest moves in city planning. Small shops are arranged along a crescent-shaped street. Influenced by Hollywood set design, curving streets provide the intriguing illusion of an endless vista, with something new always emerging around the corner.
Another powerful device is a diagonal street, which creates a visual connection between the shopping center and City Hall to the northeast. Two plazas one in the center of the shopping area and one directly in front of City Hall are oriented along this diagonal axis. The plan can be faulted for striving for spectacular effects rather than focusing on the already difficult task of creating a set of attractive, coherent streets. Notwithstanding, the original site plan was clear in its intent: The quality of the pedestrian experience was paramount, and that buildings should be molded around open spaces, rather than the opposite.
Were the developers and the money-men the culprits? It is hard to say. A presentation by the city's redevelopment director, Rich Bottarini, outlines the general requirements of commercial development. There are few surprises here. The developers need to realize an "acceptable" return on investment. To do so, they need to lease space to a certain number of "national credit" tenants. The developer and retailers both need flexibility meaning that the city's plans must be altered to meet the inflexible needs of retailers for both architecture and signage. Naturally, retailers want "an abundance of convenient parking," while both retailers and lenders want a shopping area to offer a mix of local and national tenants.
As in any large commercial project, city officials compromised with the developers. Architecture is part of the branding of national credit tenants, so the site plan must bend to accommodate them. In Pleasant Hill, the developer and major tenants substituted their own designs for the city's own site plan. There is nothing wrong with this, as long as the integrity of the site plan was preserved. But without firm planning principals, the recipe was quickly adulterated.
Tenants demand abundant parking, so the site plan opened up hundreds of spaces of additional surface parking. But there was plentiful surface parking in the original scheme. So the final, built version of downtown Pleasant Hill offers the familiar sight of buildings floating on a sea of asphalt, like any other suburban shopping center. Here, "accidental," undesigned open space that is, the space between big box retail buildings competes with the designed plazas. The crescent street fares little better. For reasons I do not understand, the promise of curving, Piccadilly Circus-type buildings along the crescent become a series of irregularly shaped lumps that do not deliver the charming novelty of the curved faηade. And the central plaza that was a centerpiece of the original site plan has been eaten away by irregularly shaped retail buildings.
Compromise does not in itself savage good planning. Planning thrives on a certain amount of irregularity, even some dissonance, as long as there is a well-established harmony from which we make a brief departure. In downtown Pleasant Hill, however, there is neither harmony nor dissonance. There is just retail. A pedestrian-oriented plan has turned into an automobile-oriented plan. The use of structured parking would have prevented the sprawling parking lots, and helped preserve the continuity of the "walk streets." True, retailers often ask for surface parking in suburban areas, but the same retailers have learned to live with structured parking in other cities, as long as customers show up.
More to the point, the city itself should have built the streets and the plazas, and subsequently invited in the retail developers. There are ingredients streets and open space that cannot be sacrificed in urban design. But in downtown Pleasant Hill, too many cooks have substituted their own agenda in place of coherent urbanism. In doing so, they have spoiled the broth.