Citizens frequently advocate creating open space — sometimes called green space — as the preferred land use when development or redevelopment of a familiar place or parcel is contemplated. Open space is often the default choice, presumed by many to be the always desirable, indisputably safe alternative to building.  Yet creating open space, a kind of one-size-fits-all idea, may be the wrong idea.  Open space is a simplistic, blanket term. It fails to describe and account for the full range of open space types, sizes, design qualities and functional attributes. Land open to the sky can be highly diverse not only in scale, form, purpose and relation to context, but also in who finances, owns, manages, programs and maintains such space.  Open spaces can be many things: intimate, passive greens or lushly planted gardens for visual delight and contemplation; simple lawns; extensive, multipurpose parks; playgrounds for children; fields for sports and recreation; and animated, programmable plazas. Open-space topography and vegetation can vary tremendously and encompass walls, terraces, benches, sculptures and water features.  [More Lewis: For D.C.’s middle class, reality can stifle the American Dream]  Over time an existing open space — park, urban plaza, preserved landscape — may need rethinking. The surrounding environment may have evolved in ways that alter use and perceptions of the space, and not necessarily for the better. The original need and justification for the open space may have diminished. Vegetation and other physical components of the space may need restoration, replacement or elimination.  A monumental public open space — the Mall — was the centerpiece of the L’Enfant plan for the nation’s capital. The L’Enfant street-block grid pattern, traversed diagonally by avenues, also envisioned numerous circles and rectangular civic parks. But it was a framework plan that neither prescribed in detail nor predicted how the city’s public open spaces would develop.  Consequently, over time, the layout, planting, furnishing and function of the Mall and the District’s civic squares, circles and parks continually changed and will continue changing.  Franklin Square, bounded by 13th, 14th, I and K streets NW, is among the largest downtown parks. Large shade trees, lawns, walkways and benches make the park attractive. But for decades the space was an outdoor haven for the homeless and was deemed unsafe. Under stewardship of the National Park Service, this commodious, favorably located federal park was underutilized.  Franklin Square may have a new life soon, thanks to efforts underway to revitalize the five-acre park. The Park Service, in partnership with the city and the Downtown Business Improvement District, has generated a new vision for Franklin Square. Makeover proposals include a park information and management pavilion with cafe and restrooms; a children’s garden and tot lot; a redesigned interactive fountain; new historical interpretive elements; and landscaping and paving upgrades.  When open space is set aside or created, the amount of space can be excessive. This is especially unfortunate when open space is provided at the expense of other desirable uses.  The attractively landscaped federal park stretching for a quarter mile along Georgetown’s waterfront is a desirable amenity for both Georgetown and the city. But this long, linear park is more than large enough to have accommodated a pavilion or two along the river’s edge, giving visitors access to food, beverages and bathrooms.  Boston’s $14.6 billion “Big Dig” demolished the old, elevated Interstate 93 expressway, a looming visual barrier between downtown and the city’s waterfront area. Replacing it is a decked-over, below-grade highway. Atop the deck is the 1.5-mile long Rose Fitzgerald Kennedy Greenway, a series of park spaces and cross streets intended to knit back together the previously divided downtown neighborhoods.  [More Lewis: Montgomery County’s design awards set laudable example for D.C. area]  Yet this was a missed opportunity. The amount of park space is more than ample. The deck structure could have been engineered to enable air-rights development spaced appropriately at intervals along the deck, overlooking the landscaped parks. The development also would have helped finance the Big Dig.  All zoning ordinances have open-space requirements for buildings and lots. Minimal yard sizes and street setback dimensions, and maximum lot coverage percentages, are intended to foster health, safety and environmental sustainability. Open spaces around buildings ensure adequate daylight, air, natural ventilation and groundwater absorption, as well as emergency egress and emergency vehicle access.  But zoning regulations are mute about design or daily use of required open space. And they sometimes grant density and height bonuses if developers provide more than required amounts of open space, regardless of actual open-space needs.  For example, along mid-town Manhattan avenues, developers once were able to construct taller high-rise office buildings if buildings were set back from the avenue to create large, paved, unencumbered entry plazas.  But these barren plazas — heat sinks in summer, cold and wind-swept in winter — were used mostly for entering and exiting buildings. New York City ended up with an excess of density-bonus plazas deadening rather than animating avenue activity.  Regrettably, open space often ends up being merely residual space, purposeless areas left over after buildings, drives and parking have been sited on a tract of land.  Reflexively calling for generic open space as the default land use should be avoided. Instead open spaces should be thoughtfully and rationally conceived. And planning always should begin with basic questions about need, context, size and scale, function, landscape design, sustainability, finance, ownership and maintenance.  Roger K. Lewis is a practicing architect, a professor emeritus of architecture at the University of Maryland and a regular guest commentator on “The Kojo Nnamdi Show” on WAMU (88.5 FM).
Without consideration of vital factors, many a plaza or other open area can become a frightful dead zone.