Images of flooding New Orleans – literally the destruction of a major American city and loss of much of its population – have increased awareness of flood risk in the US. In California, the Sacramento-San Joaquin Delta has been much in the news recently, as the fragility of its levees (long understood by experts, but only recently appreciated by the public) has attracted the governor’s attention, leading him to propose massive re-investment. But even with higher, heavier levees, will the Delta be safe from flooding? Given the unique characteristics of the Delta, does it make sense in the long run for us to build houses below sea level there? Or could alternative scenarios that preserve open-space and infrastructure values provide more benefit and less risk to the San Francisco-Sacramento-Stockton metropolitan region of the future?
In hopes that this fresh experience created a ‘teachable moment,’ the Department of Landscape Architecture and the College of Environmental Design held a two-day symposium, ReEnvisioning the Delta, to consider the implications of the Delta’s ongoing urbanization and to explore alternative futures for the region. The symposium featured presentations on the physical characteristics and unique functions of the Delta, emphasizing its key role for infrastructure, agriculture, and open space within the San Francisco-Sacramento-Stockton metropolis, and on the dynamics of urbanization in the Delta and the surrounding region.
Urbanizing lands below sea level in the Delta strikes many as manifestly unwise and dangerous. Nonetheless, it is occurring now, at a rapid rate. Hans Johnson presented population data showing that the Delta is the fastest growing region in California, with population increasing at rates even faster than developing nations. Panel presentations by Carol Whiteside (former mayor of Modesto), Marci Coglianese (former mayor of Rio Vista and member of the Delta Protection Commission), and John Cain (Natural Heritage Institute) explained how escalating housing prices and a pro-growth political environment in local government are creating the enormous pressure to urbanize flood-prone lands. The author of the Delta Protection Act, former State Senator Patrick Johnson, showed how even the Delta Protection Commission established by the Act is not immune from these incentives to sprawling growth.
Bob Twiss presented an overflight of the Delta landscape that showed how these developments are consuming critical lands at the edge of the Delta that may be essential for future ecosystem management. Graduate student research completed for this symposium also projected future urbanization from general plans, proposed development footprints, aerial imagery, and other relevant GIS data layers. This is the first spatially explicit analysis of urbanization below sea level in the Delta and the likely consequences of that urbanization in the event of catastrophic flooding.
And that disaster potential is escalating. UCB Engineering Professor Ray Seed, who has just completed an NSF-funded study of levee failures in New Orleans, argued that the levees in the Delta are extraordinarily vulnerable to an earthquake-induced mass failure (although techniques exist to make them safe through extended public investment). The current 100-year flood protection standard to which the levees are built, meanwhile, leaves a very significant “residual risk” of a larger-than-100-year flood that could be immensely destructive. Tom Philp of the Sacramento Bee moderated panelists Mike Webb (California Building Industry Association), Ron Baldwin, (Director San Joaquin County Emergency Operations), and Tom Zuckerman (University Pacific, former counsel Central Delta Water District) in a discussion of the varying opinions on how to moderate disaster risks and who should be responsible for levee safety and potential liability.
The second day examined potential futures for the Delta, focusing on the Delta not as a set of problems, but as a place with its own unique history and character. As Jane Wolff, author of the Delta Primer, pointed out, it is a place that can be seen in several different ways — as at once an open space, an agricultural region, a wetland habitat, a recreational region, and an economic resource.
Subsequent talks shared the experience of land conservation efforts for each of these types of landscapes. Louise Mozingo argued that the creation of Central Park in New York and the Emerald Necklace in Boston show that recreational open spaces can be formed in advance of urbanization. Phyllis Faber showed that the history of agricultural land conservation in Marin County contains valuable lessons for the situation Delta farmers are facing. Bob Twiss talked about the land-use controls undertaken at Lake Tahoe to protect water quality, another pressing issue for the Delta today. Santa Monica Mountains Conservancy director Joe Edmiston advocated the use of a state-sponsored Conservancy model to protect conservation values in the Delta. Joe Bodovitz recounted the balancing of conservation and development in San Francisco Bay planning, and Pete Rhoads talked about the enormous planning effort underway to restore the Everglades. The Delta bears important similarities to each of these cases. Other panels, including such notables as John King of the San Francisco Chronicle, Margit Aramburu, formerly of the Delta Protection Commission, and Tom Waters of the US Army Corps of Engineers, expounded on some of these similarities and offered suggestions for moving forward in the Delta.
Innovative ideas for preservation of the Delta’s critical infrastructure, agriculture, and open-space access were also presented by Jennifer Brooke on behalf of the graduate students involved in the annual Tommy Church Design Competition. Interdisciplinary student teams developed plans and designs for a Delta park, recognizing its central role in the San Francisco-Sacramento-Stockton metropolis of the future. The jury awarded two first prizes to the teams of “Wet Feet Wanted,” (Elke Grommes, Mei Minohara, and Zachary Rutz), and “Delta Byways,” (Brooke Ray Smith and Stephen Miller).
Between historical precedents and visionary designs for the Delta’s future, there was no shortage of thought-provoking ideas for this critical region of California. What is needed, participants agreed, is better planning data and, more importantly, a widely shared vision for what the Delta should look like in the future. With the urbanization problem now on the political radar screen, planning efforts can now turn to the challenge of creating that vision of a more secure and resilient Delta region.
The Napa River Watershed drains into San Pablo Bay, and is home to the world famous wine region of Napa Valley as well as several small to moderate sized cities. With its headwaters at Mount St. Helena, the Napa River flows from wild slopes of the Mayacmas Mountains through picturesque vineyards toward and through the City of Napa and out past Mare Island and the city of Vallejo to San Pablo Bay. One of the most memorable and well-known geographic features in California, the Napa Valley is a highly compact watershed ranging from near wilderness to rural lands, to suburbs, to cities, to industrial zones in a mere fifty miles.
Beneath the surface of this apparent paradise is a web of relationships highly dependent on fossil fuels. From the natural gas providing electricity to homes, wineries and businesses to the oil providing gasoline for vehicles, and the petrochemicals for agriculture, the valley is held captive by the fossil fuel era. Like all regions of North America, the Napa Valley will of necessity undergo a very serious transformation to a post-fossil fuel reality. A compact, thriving watershed region like the Napa Valley allowed the class a laboratory to explore the patterns of land use and landscape that may emerge in the wake of declining fossil fuel supplies and the realities of global warming. The class presumption was simple: In thirty years, everything will change. Their job was to anticipate that change and guide it in constructive, fulfilling directions for all life forms and resources.
Led by Assistant Professor Jennifer Brooke and Beatrix Farrand Visiting Professor Robert Thayer, Professors Joe McBride and Matt Kondolf, and with the cooperation of the Napa County Environmental Planning staff members, students broke into six teams to investigate a number of critical dimensions of the river valley: Water; Land and Vegetation; Energy and Transit; Housing, Urban and Industry; Parks, Open Space and Tourism; and Agriculture, Food and Wine. These analysis teams conducted exhaustive reconnaissance on the state of the Napa River watershed with a view of likely conditions, potentials, and limitations thirty years out, when transit fuels would be more scarce and expensive, weather more extreme, population pressure more acute, and natural habitat and open space more precious.
Analysis processes were immediately followed by a master planning phase wherein student teams focused their efforts on components necessary to direct the future of the region. One team hypothesized the creation of a quasi-public initiative entitled “Common Roots”, a new twist on the contemporary CSA (Community Supported Agriculture) movement, proposing a multifaceted urban agricultural growing and distributing system with neighborhood markets and a centralized farmers market. With the goal of returning potentially productive but underutilized lands to the provision of local food, their presentation included a toolkit of strategies for small-scale, decentralized food production. Their work also included the addition of an Urban Agriculture element to the City of Napa zoning code, which would enable urban food production to be facilitated by local government yet run by a local non-profit board of directors.
Another team branded itself as “THINC Transit”, an acronym standing for “Transit Hybrid for an Integrated Napa Community”, and proposed a sophisticated yet highly feasible public transit system utilizing existing Wine Train rail rights-of-way and linking other potential transit corridors with existing BART and Amtrak lines to provide ferry, train, light rail, bus, and shuttle transit for the entire valley. Their final presentation included a highly detailed phasing plan for implementing the transit system, complete with a hypothetical and multi-modal schedule of arrivals and departures, including a by-reservation shuttle for the remote valley towns of St. Helena and Calistoga.
In the final design phase, individual students chose site-specific design projects that would build upon various goals and findings from the analysis and master planning efforts completed earlier. These included a complex transit center expansion on the site of the BayLink Ferry in Vallejo; an adaptive reuse plan to turn a routine industrial park into a showcase venue for local organic food production, distribution and waste management; a combined constructed wastewater wetland/regional park and trail complex for Mare Island; a mixed use affordable housing community built on the abandoned glider port in Calistoga; upgraded recreational and habitat improvements to the estuarine wetlands near the Napa airport; and dense transit-oriented development of land along the proposed light rail line through the City of Napa.
Running successfully through the entire course was the theme of “Not Business as Usual.” In envisioning the rather substantive changes anticipated with respect to climate, rising sea levels, the peaking of oil, increases in population quantity and social diversity, potential widening of income gaps, and the future need to shorten the supply chain distance between sources and end uses of energy, food, water, and materials, class members prepared themselves for a future where the skills of landscape architects and environmental planners, as some of the most logical systems thinkers, will be most sorely needed.
Previously, transportation planners viewed movement by foot and bicycle as recreational, rather than legitimate transport to be seriously considered. A major shift in policy away from auto-centric planning, to mandated accommodation of the pedestrian and bicycle in federally supported transportation projects has stimulated numerous pedestrian and bicycle policies, plans, and built projects across the country. Recent studies on the many health benefits of walking have helped strengthen the case for making walkable cities.
Urban Design, Transportation Planning, and the Pedestrian
Urban design and transportation planning have evolved along distinctly different tracks over the past century, urban design focusing on the concrete experiential qualities of the built environment, generally at small to medium scale, and transportation planning focusing on more abstract function and efficiency for the motorist, at the scale of cities and regions. Before the “scientific” revolution in transportation planning, civil engineers in the U.S. were trained to deal with the character of the locale. The road was engineered to serve transportation needs, but also to fit in with the landscape and to enhance the experience of the user.
Beginning in the 1930s the profession of street and road design split in two separate directions: those who specialized in the technical aspects of transportation planning and engineering, and those who dealt with place-based design. While transportation planners have focused on abstract “macro” variables like capacity, demand, rate of flow, trip origin/destination analysis, congestion patterns, and regional land use patterns, urban designers and landscape architects have looked at “micro” variables, the form and use of local places. The consequences of this split for pedestrians and the built environment have been enormous.
Walkable Cities of the Past
Walkability was essential in cities before the automobile era. Streets of the preindustrial city were by necessity walkable, since everyone depended upon ready access by foot or slow moving cart, wagon, or carriage for access to jobs and the marketplace. Activity patterns had to be fine grained, density of dwellings had to be relatively high, and everything had to be connected by a continuous pedestrian path network. Cities of the middle ages were remarkable in their walkability and typically packed all the necessities of urban living into an area no more than ½ mile from the central square. For example, the entire built-up area of Urbino, Italy occupied only 300 acres yet housed 30,000 people. Early American cities like Boston were highly walkable, as well. Before major land filling operations began in the early nineteenth century, everything was on a small peninsula of little more than 800 acres where every point could be reached in a walk of less than one mile or ½ hour. Despite enormous growth and modernization, the central area still maintains its walkability, a rare situation for the American city.
High speed transport and the quest for efficiency killed the walkable city. Each advance in transportation technology — from horse drawn cart or carriage, to horsedrawn streetcar, to electric streetcar, to automobile and superhighway — has degraded the pedestrian environment. Hazardous high speed traffic broke up the fine grained pedestrian network and imposed barriers to free movement on foot. In ignoring the pedestrian experience, the street lost its intimate scale and transparency, and became a mere service road, devoid of public life. Modernist planning and design separated pedestrians from the automobile, shunting them off to raised plazas, skywalks, barren “greenways,” and sterile pedestrian malls. The automobile oriented values of Modernism have been codified in the transportation and street design standards that we struggle with today.
In the late postindustrial city it is impossible for the pedestrian or bicyclist to navigate freely. The street patterns of most residential areas built after 1950 are based on the discontinuous cul-de-sac rather than the interconnected grid. Block sizes are too large to permit a range of route choices and land use patterns are coarse with activities widely spaced and segregated by type. Streets are often over scaled and inhospitable to pedestrians and frequently lack sidewalks in order to reduce infrastructure construction and maintenance costs. The entire system has been designed for the convenience of the motorist (Southworth and Ben-Joseph 2003).
The benefits of increasing walking are now recognized. Walkability is the foundation for the sustainable city; without it, meaningful resource conservation will not be possible. Like bicycling, walking is a “green” mode of transport that not only reduces congestion, but also has low environmental impact, conserving energy without air and noise pollution. It can be more than a purely utilitarian mode of travel for trips to work, school, or shopping, and can have both social and recreational value. It is also a socially equitable mode of transport that is available to a majority of the population, across classes, including children and seniors.
Compared with Europeans, Americans walk very little. Only 9 percent of total trips in the U.S. were by foot in 1990 but 84 percent were by car, whereas in Sweden 39 percent were by foot and 36 percent were by car. In The Netherlands and Germany walking and bicycle trips increase with age and account for over half the trips for people age 75 and older (Pucher and Dijkstra, 2003). In addition, only 6 percent of trips were by foot for Americans age 75 and older in 2000. (Frank et al 2003).
Walking can promote mental and physical health including cardio-vascular fitness, reduced stress, stronger bones, weight control, and mental alertness and creativity. Walking is the most accessible and affordable way to get exercise. As obesity has now become a major public health problem in the U.S., several studies have made connections between health and the design and planning of cities. They make a strong case for better design and planning of the pedestrian environment.
- Three quarters of U.S. adults do not get enough physical activity, and one quarter is inactive in their free time. Nearly two thirds (64.5 percent) of U.S. adults are overweight and almost one third are obese according to a recent National Health and Nutrition Examination Survey (Ewing et al 2003). In contrast, European countries with the highest rates of walking and bicycling have less obesity, diabetes, and hypertension than the U.S. (Pucher and Dykstra 2003).
- As little as ½ hour moderate activity such as walking or bicycling may be adequate for long term health, but only one quarter of the population achieves this (Frank et al 2003; Powell et al 2003).
- People who live in “sprawl” are likely to walk less, weigh more, and have greater incidence of hypertension than people living in more compact areas (Ewing et al 2003). Residents of more walkable San Diego neighborhoods engaged in 70 more minutes of physical activity in the previous week and had less obesity; 60 percent of residents in less walkable neighborhoods were overweight (Saelens et al 2003).
- Women between the ages of 70 and 81 who did more walking and other physical activity tended to have better cognitive function and less cognitive decline than those with less activity. Those with the highest levels of physical activity had 20 per cent lower risk of cognitive impairment (Weuve et al 2004). Men over 71 who walked the least (less than ¼ mile per day) had nearly twice (1.8 times) the risk of developing dementia as those who walked the most (Abbott et al 2004).
- People who live in walkable neighborhoods may have higher levels of “social capital,” and are more likely to know their neighbors, participate politically, trust others, and be socially engaged (Leyden 2003).
Criteria for the Walkable City
“Walkability” might be defined as the extent to which the built environment supports and encourages walking by providing for pedestrian comfort and safety, connecting people with varied destinations within a reasonable amount of time and effort, and offering visual interest in journeys throughout the network.
What are the qualities of a walkable city? To encourage walking designers and planners need to go beyond utilitarian access and address several qualities of the path network.
1. The path network should be well connected without major gaps or barriers, both locally and in the larger urban setting. Connectivity of the path network is determined by the presence of sidewalks and other pedestrian paths and by the degree of path continuity and absence of significant barriers. While it is tempting for simplicity to measure walking distance to destinations radially “as the crow flies,” this approach can be misleading, especially when street patterns are coarse and fragmented. However, as patterns become finer grained and more interconnected, blocks become smaller with higher connectivity of paths, and the ratio of access for the “crow fly” measure to actual walking distance approaches 1:1.
In addition to path distances to various points, it is important to examine the amount of path choice. Density of path intersections and block sizes can be revealing: a high density of intersections and small block sizes usually correlates with a high degree of connectivity. Barriers to pedestrian access such as cul-de-sacs and dead end streets, or busy arterials, railroad or power line rights-of-way, rivers, or topographic features must be minimized.
Connectivity is best addressed when an area is being designed, of course, and is much more difficult to remedy once a place is built. Most of the post-industrial suburban landscape suffers from lack of pedestrian connectivity, typically with a pattern of disconnected cul-de-sacs and barrier arterials and highways. In some cases, connectivity retrofits might be possible, with pedestrian overpasses or underpasses across barriers, or traffic calming devices. Cul-de-sacs might be connected to provide a continuous bicycle and pedestrian system (Southworth and Ben-Joseph 2004).
2. Pedestrian paths should be linked seamlessly, without interruptions and hazards, with other modes such as bus, streetcar, subway, or train, minimizing automobile dependence. Walking and bicycling are now seen as essential ingredients in an integrated, intermodal transportation system to give travelers transportation options and to provide continuity from home to destination. Beyond providing an internally well-connected pedestrian network, it is important to provide connectivity with the larger city and region through convenient and accessible links to other modes such as bus, streetcar, subway, or train within a reasonable time-distance. This means that stations need to be spaced frequently enough to allow pedestrian access for residential and commercial zones, usually ¼ to ½ mile, or a 10 to 20 minute walk. A complete pedestrian network will offer full connectivity between all modes so that one can navigate seamlesslessly from foot to trolley or subway to train or air without difficult breaks. A small pedestrian district, no matter how well designed, cannot contribute to a reduction in automobile use if it is not well supported by transit and situated within an accessible mix of land uses.
3. Land use patterns need to be fine grained and varied, especially for local serving uses, so that pedestrians can actually walk to useful destinations. Studies have indicated that distance to destinations is the single factor that most affects whether or not people decide to walk or to take the car, and is more of a determinant than weather, physical difficulty, safety or fear of crime (Funihashi 1985; Handy 1996; Komanoff and Roelofs 1993). Several studies have found that the distance Americans will walk for typical daily trips is quite limited, ranging from 400 feet to about ¼ mile (Weinstein1996). Untermann found that 70 percent of Americans would walk 500 feet for daily errands and that 40 percent would walk 1/5 mile; only 10 percent would walk ½ mile (Untermann 1984).
A walkable neighborhood or city has an accessible pattern of activities to serve daily needs. This means that one can reach most local-serving uses on foot within 10 to 20 minutes or up to ½ mile. The types of activities that fall within this “neighborhood access” category include shops, cafes, banks, laundries, grocery stores, service stations, day care centers, fitness centers, elementary schools, libraries, and parks. However, most post-industrial development in the U.S. has lost walkability and the necessary fine-grained pattern of uses so that it is impossible in many areas to reach even one everyday activity on foot within ½ mile.
Could a very low density city ever become walkable? Land use intensity and diversity, like connectivity of the path network, are best established at the very beginning of the development process. Once a low density coarse grained pattern is put in place, it is a legal and physical challenge to insert density and variety.
4. The pedestrian network needs to be safe for people of varied ages and degrees of mobility, both from traffic hazards and crime. Perhaps the best understood and most fully developed aspect of walkability is pedestrian safety. In most U.S. cities transportation and land use policies have made walking and bicycling inconvenient, unpleasant, and dangerous. Each year 6000 pedestrians and bicyclists are killed in traffic in the U.S.; pedestrians are 23 times more likely to get killed than automobile passengers (Federal Highway Administration 2003). Environments that maximize fast and efficient auto travel are rarely enjoyable or safe for pedestrians and bicyclists.
A recent trend across the country has been “traffic calming,” techniques for making streets more pedestrian friendly by slowing down traffic through a variety of devices: chokers, chicanes, speed bumps, raised crosswalks, narrowed streets, rough paving, traffic diverters, roundabouts, landscaping, and other means.
5. Pedestrian paths need to be well designed in terms of width, paving, landscaping, signing, and lighting. The quality of the path itself, of course, is essential to walkability. Perhaps the least hospitable pedestrian path is the auto oriented commercial strip, a treeless expanse dominated by several lanes of noisy traffic, polluted air, glaring lights and raucous signs. The street has few, if any, designated crosswalks and is much too wide for a pedestrian to cross comfortably. The chaotic frontage is poorly defined, lined by blank big boxes, large parking lots, and drive-in businesses. Haphazard utility poles and boxes, street lights, traffic control signs, hydrants, mail boxes and parking meters dominate the sidewalk, which is constantly interrupted by driveways to businesses (Southworth and Lynch 1974).
If the strip is pedestrian hell, then the ideal pedestrian path will provide for the comfort and safety of pedestrians of varied ages and physical abilities. It should be continuous, without gaps, and should have a relatively smooth surface without pits, bumps, or other irregularities that could make walking and wheelchair access difficult. It should be at least wide enough for 2-3 people to pass one another or to walk together in groups, and much wider in very urban situations. Terrain can be a significant factor in walkability, especially in cities with snow and ice. Encroachments into the pedestrian right-of-way such as utility poles, mail boxes, or newspaper vending machines can compromise walkability by constricting the pathway or blocking crossings. Landscape elements such as planted verges help insulate the pedestrian from the moving traffic, and street trees provide protection from the sun and help define the street space. Pedestrian scaled path lighting can enhance nighttime walking and provide a greater sense of safety.
6. The path context, including street design, architecture and landscape, needs to offer visual interest and overall explorability. Perhaps the most problematic and least developed of walkability criteria are those related to quality of the path context. A safe, continuous path network in a monotonous physical setting will not invite pedestrians. The path network must engage the interest of the user. Many aspects of the path context can contribute to a positive walking experience: visual interest of the built environment, design of the street as a whole, transparency of fronting structures, visible activity, views, lighting, and street trees and other landscape elements.
The postindustrial city has become an increasingly closed and hidden world as processes of production and marketing are hidden from view. Big box shopping, introverted shopping malls and office parks, vast parking lots and reliance on electronic communications have all contributed to urban landscapes that are difficult to read. A transparent environment allows one to sense the social and natural life of a place through first hand observation. Such qualities are impossible to deal with at the macro scale of most transportation analysis and planning, but require detail design and attention to the special qualities of places. In most large developments of mass produced housing, repetitive architecture and uniform street designs devoted to the automobile have produced neighborhoods with little pedestrian appeal.
In the past century a few notable exceptions to the general trend of post war development have sought ways of maintaining pedestrian access, while accommodating the automobile. In the 1920s and 30s, Clarence Stein structured his designs for new garden suburbs such as Greendale, Wisconsin and Radburn in Fairlawn, New Jersey around a continuous green core with pedestrian and bicycle paths that connected homes with school, local shops, and transit. In Britain in the 1960s, Gordon Cullen and others developed plans to restore or reinvent the traditional townscape as an engaging “sequence of revelations” for the pedestrian (Cullen 1961). The idea is still alive, although not commonly seen, in places like Village Homes in Davis, California and Reston, Virginia. Many New Urbanist developments emphasize walkability, as well. In The Kentlands in Gaithersburg, Maryland particular design attention was given to creating pedestrian scaled streets with varied architecture and landscape. Small-scale detail along the streets, as well as changing vistas and focal points from neighborhood to neighborhood make it an enjoyable place to go for a walk. Every district has numerous alternate pathways. It has been so successful in this regard that people drive to it from other suburbs just to take a walk (Southworth, 1996). In all of these cases walkability has been an important feature, but regrettably each of the developments is a rather small, auto dependent island stranded in motopia.
There is no general theory of spatial design for the pedestrian environment that applies everywhere. Although many urban designers have attempted to develop formulas for street width, setbacks, or ratios of enclosure height to street width, for every rule that is made, examples of successful streets can be found that break the rule. The canyon streets of Manhattan are often perceived as attractive and walkable, as are the small seventeenth century lanes of Marblehead, or the broad tree-canopied boulevards of the Country Club district of Kansas City. Street trees and other vegetation almost always enhance walkability, but several European examples immediately come to mind that violate this ideal such as the treeless, arcaded streets of Bologna or the stone streets of Venice, Florence and Sienna. Here the architecture, street space, and street life provide the interest and engage the pedestrian in exploration. Many U.S. neighborhoods such as streetcar suburbs built from the 1880s to 1920s are rather nondescript architecturally, but still have a high degree of walkability. They are valued for the comfortable scale of the streets and blocks, the canopy of street trees, the variety of architectural expressions, and the connection of buildings to the street.
Successful approaches will vary by culture, place, and city size. Nevertheless, a few attributes are likely to contribute to the quality of path context in most urban and suburban settings: scale of street space, presence of street trees and other landscape elements, views, visible activity and transparency, scale and coherence of built form. The important thing is to engage the pedestrian’s interest along the route.
It will not be easy to achieve walkable cities in the U.S., especially since more than half of the typical American metropolis has been built according to automobile dominated standards. There may be resistance to improving things for the pedestrian or bicyclist, fearing space will have to be taken away from the car. Often it is more difficult to retrofit built-up areas because the patterns are already established. While it is not impossible to retrofit existing street networks to serve pedestrians and to insert some density and mixed uses into low density cities, it will require imagination and persistence.
To create the walkable city in the automobile age, emphasis will need to shift from almost total auto orientation, to acceptance and promotion of pedestrian and bicycle access at all levels. The regulatory environment will need to shift toward encouragement of walkability, and the design and planning professions will need to work toward creation of integrated pedestrian access at all scales of movement. The tasks are challenging but the benefits for urban life will be substantial. A focus on the walkable city will transform the way we live in fundamental ways, benefiting health, social relations, and the natural environment.
I am grateful for the assistance provided by Raymond Isaacs, Sungjin Park, and Jeff Williams.
For a more detailed discussion of this subject see: Southworth, Michael, “Designing the Walkable City,” Journal of Urban Planning and Development, Fall 2005.
Abbott, R., White, L., Ross, G., Masaki, K., Curb, J. and Petrovitch, H. (2004). “Walking and dementia in physically capable elderly men.” Journal of the American Medical Association, 292 (12) 1447-1453.
Cullen, G. (1961). Townscape, The Architectural Press, London.
Ewing, R., et al (2003). “Relationship between urban sprawl and physical activity, obesity, and morbidity.” American Journal of Health Promotion 18(1) 47-57.
Federal Highway Administration (2003). Accommodating bicycle and pedestrian travel: A recommended approach, Federal Highway Administration, Washington, D.C.
Frank, L., Engelke, P., and Schmid, T. (2003). Health and community design: The impact of the built environment on physical activity, Island Press, Washington, D.C.
Funihashi, K. (1985). A study of pedestrian path choice. Working Paper. Center for Architecture and Urban Planning Research, The School of Architecture and Urban Planning, University of Wisconsin, Milwaukee.
Handy, S. (1996). Urban form and pedestrian choices: Study of Austin neighborhoods, Transportation Research Record, 1552: 135-144.
Komanoff, C. and Roelofs, C. (1993). The environmental benefits of bicycling and walking, National Bicycling and Walking Study, Case Study No. 15, Federal Highway Administration, Washington, D.C.
Leyden, K. (2003). “Social capital and the built environment: The importance of walkable neighborhoods.” American Journal of PublicHealth 93(9) 1546-1551.
Powell, K., Martin, L., and Chowdhury, P. (2003). “Places to walk: convenience and regular physical activity.” American Journal of Public Health 93(9) 1519-1521.
Pucher, J., and Dijkstra, L. (2003). “Promoting safe walking and cycling to improve public health: lessons from the Netherlands and Germany.” American Journal of Public Health 93(9) 1509-1518.
Saelens, B., et al (2003). “Neighborhood-based differences in physical activity: An environment scale evaluation.” American Journal of Public Health 93(9) 1552-1558.
Southworth, M. (1996). “Walkable suburbs? An evaluation of neotraditional communities at the urban edge.” Journal of the American Planning Association, Winter.
Southworth, M., and Ben-Joseph, E. (2003). “Reconsidering the cul-de-sac.” Access, Spring.
Southworth, M., and Ben-Joseph, E. (2003). Streets and the shaping of towns and cities, Island Press, Washington, D.C.
Southworth, M., and Lynch, K. (1974). “Designing and managing the strip.” in City Sense and City Design: Writings and Projects of Kevin Lynch, Banerjee, T. and Southworth, M., eds, MIT Press, Cambridge.
Untermann, R. (1984). Accommodating the pedestrian: Adapting towns and neighbourhoods for walking and bicycling, Van Nostrand Reinhold, New York.
Weinstein, A. (1996). Pedestrian walking behavior: A review of the literature. Working Paper, University of California at Berkeley.
Weuve, J., Kang, J., Manson, J., Breteler, M., Ware, J., Grodstein, F. (2004). “Physical activity, including walking, and cognitive function in older women.” Journal of the American Medical Association, 292(12) 1454-1461.
Contemporary energy conservation efforts emphasize architectural and engineering solutions. Green building is a trend, still divorced from the landscape and the garden, both which are green to begin with. Integral to any discussion of sustainability or green building should be a consideration of the capacity of the designed landscape to create and modify microclimates and thus conserve energy.
Prior to the oil embargo of 1973 which alerted the world to its overdependence on diminishing fossil fuel reserves, building and growth patterns had become extremely wasteful. In reaction to the prevailing attitudes that our energy supplies were inexhaustible, many architects and landscape architects began to investigate passive design techniques. Unfortunately, our fascination with later Information Age technologies diverted our attention away from these early advances and investigations.
Many of the principles of passive design explored in the 1970s had their origins in the distant past. Throughout landscape history, the harsher the climate, the more ingenious the devices and methods became for creating physically comfortable spaces. A review of historical gardens would reveal many precedents for energy efficient design. In fact, the principles of climatic site planning reach back thousands of years. In Mediterranean climates, such as ours, people lived in close connection with the landscape, adapting their environments to create comfortable living spaces by observing natural patterns and systems. One doesn’t need a complex computer model to understand how the sun moves across the sky.
The move towards an energy responsive ethic provides us with a second chance to incorporate the knowledge and methodologies from our ancient and recent pasts and implement these ideas on a large scale.
EarthAs early 36 BC, Varro identified the southeast-facing hillside as the ideal location for a villa. (The form of the typical “suburban” villa included house and grounds together with the total complex understood as a unit.) The southeast orientation allowed the dwelling and the garden to catch the prevailing summer breezes and block the cold northern winds in winter.
During the Renaissance there existed a “Canon of Horticultural Rule” which presented a format for placing elements in the landscape. According to the canon, the bosco or planted woodland was an integral element of the site plan. A dense plantation of evergreen trees placed on the northern side of a structure not only blocked the winter winds, but also played an important ecological role, providing abundant vegetative mass for photosynthesis and wildlife habitat. This is an extremely important lesson for contemporary design: establishing a ratio of vegetative mass to built form and maximizing tree canopy can provide great climatic benefit. A plantation mass can effectively block the sun, and thus reduce ground level temperatures and insulate buildings. Planting large areas of deciduous trees with broad canopies will produce significant quantities of oxygen, while reducing ambient temperatures in the summer.
Contemporary ideas of passive solar design are also rooted in history. All living material can trace its origins to the heavenly fire. Without the sun we cannot thrive. In the past, solar orientation was a guiding principle in laying out garden and dwelling. Leon Battista Alberti promoted the common-sense use of passive solar design as long ago as 1482. He believed that loggias should be designed not only to capture beautiful views, but also to provide year round comfort by admitting sun or breezes, depending on the season. Alberti even proposed the use of glass to keep out the winter wind and let in the undefiled daylight.
Pliny the Younger’s Laurentine villa near Rome contained a unique solar device called the heliocaminus, or heated sunbath, which was a garden room enclosed on four sides and open to the sky to capture the sun’s rays. The solar-heated heliocaminus of the Romans evolved into the giardino segreto or secret garden, ever popular in Italian Renaissance gardens. Usually a sunken space with decorative stone or stucco walls, the enclosed room deflected cold winds and collected heat from the sun. One of the finest examples of the giardino segreto can be found just outside of Florence on the grounds of the Villa Gamberaia. Located directly across from the central entrance to the villa is a narrow secret garden, hardly more than 20 feet across and 100 feet long. This diminutive garden runs east to west to ensuring exposure to the morning and afternoon sun.
Being aware of the movement of the sun also allowed Renaissance designers to develop garden elements for the year-round growth of crops. The limonaia was one of the first solar-powered spaces in temperate climates that harnessed and stored solar energy for the winter storage of citrus plants. Similar in form to the loggia, the limonaia faced south and was enclosed with large plates of glass, like a greenhouse. Operable windows regulated interior heat. Plants were placed on tiered platforms at the base of the solid north wall to receive plenty of sunlight.
The Villa Medici at Castello, a few miles from Florence, had over 300 varieties of fruit trees in cultivation, essentially making this villa a functioning agricultural landscape set within a beautiful formal garden. The ornate formal gardens of the Italian Renaissance, so often criticized as exercises in geometry imposed on nature, continue to have relevance for designers and planners today. As agricultural centers they provided sustenance for not only their owners, but the families that cultivated and maintained them. Most of the farming villas produced cash crops and could be considered self-sustaining in many respects.
The limonaia, integral to the Italian garden, can be retrofitted into contemporary gardens to serve as the foundation for sustainable communities. Relevant today for its ability to capture and store the sun’s heat, a limonaia can be an instrumental device for growing food as we move towards a more sustainable future where gardens provide not only beauty, but sustenance.
AirGarden designers have sculpted the movement of air and designed air-cooled spaces throughout history, particularly in Mediterranean climates. Today’s designers can exploit the cooling effects of moving air to reduce the energy and environmental costs of using mechanically-cooled air-conditioning systems. Microclimates can be designed to take advantage of the cooling properties of air flow. Air can be directed, funneled, and accelerated with simple landscape and architectural forms such as seats, arbors, pergolas, garden pavilions and porches.
The Alcazar Gardens of Seville contain one of the cleverest air-cooled seats in garden history. This extraordinary bench is situated in the Jardin de la Danza, a small garden room within a series of enclosed patios. Extremely thick walls enclose the garden on the east and west, while the southern wall addresses the prevailing summer breezes with an intimate niche. Between two built-in benches, a small arched window with a decorative metal grill frames a picturesque view of the adjacent lower garden. As the breeze flows, it is forced through the small window, thus increasing its velocity at its point of exit on the opposite side of the opening. (We now understand this phenomenon as the Venturi Effect.) In addition to being naturally air-conditioned, the enclave remains cool in the summer because the thick walls that enclose it act as an insulator, while the white walls reflect the heat produced from the intense rays of the sun. This ingenious form of air conditioning remains effective to this day.
Alleés are parallel rows of evenly planted trees placed on either side of a path, avenue, or roadway, and are usually long enough to create a walk or promenade of some distance. They are commonly used to direct views, organize spaces, create vistas, and unite various parts of a garden. An alleé can also stimulate the movement of air and be used to direct air currents into specific areas of the garden, garden structures and dwellings. When planted along south-facing slopes, alleés benefit from naturally rising air currents that push air from the shaded space into building interiors.
In desert climates garden pavilions were commonly built with a south-facing porch balanced over a large pool. The shaded interior porch with its high ceiling would catch the cooled air that passed over the pool. Many variations were possible, but a connection to the garden was essential. To augment the cooling effect of the porch, the Persians suspended a curtain from the façade of the pavilion to block the hottest rays of the summer sun. The curtain was pulled back in the winter to allow the sun to enter and warm the space. A soft and luminous quality of light filtered through the fabric. When the curtain was fully extended over the pool, it acted as a large air scoop, concentrating the ephemeral breeze, and capturing water evaporating from the pool. In addition, the cloth could be moistened with rose water, cooling and scenting the interior as the moisture evaporated. The Persian garden pavilion and the Italian summer house are both designed for natural coolness. As intelligent passive design devices they represent relevant footprints for reducing energy consumption in the contemporary built environment.
WaterThe importance of water as a commodity cannot be underestimated, especially in California. Without water there can be no life. And in past cultures, the collection, storage, and movement of water was a priority in order to maintain a predictable supply throughout the year. Only then could passive microclimates be enjoyed and the art of the garden flourish.
In California, every drop of water that falls on a site should be captured and stored. Extremely high temperatures combined with lengthy droughts have turned the American west into a tinderbox. In many regions of the world water is being used more quickly than aquifers can be replenished. Water tables are falling. If this trend continues it will have a profound impact on food production and living standards.
The control and disbursement of water in California has become a politically explosive issue. Perhaps only through enlightened watershed management and a change in public attitudes toward consumption can a dependable supply of clean water be preserved. Continued research of both historical precedents and current technologies, combined with the promotion of sustainable agricultural practices, are the first steps towards redefining our relationship with water. Water is not merely a resource to be exploited for human convenience, but rather a nurturing force that links and sustains all life on earth.
In many arid climates cisterns were used as a fundamental method of storing as much rain water and runoff as possible for use during the dry season. In Los Angeles, before aqueducts brought water from the north, residential cisterns were critical elements in a system that had to balance the effects of both droughts and floods. This tradition can be resurrected in the contemporary landscape. Runoff can be directed into insulated closed cisterns built into new structures or retrofitted into existing structures.
Long before modern drip irrigation, the Persian gardener developed a simple yet efficient method for subsurface irrigation. In Yazd, one of the hottest spots on the Iranian plateau, “condensing jars” significantly reduced the amount of water lost to evaporation. Earthenware containers were placed in the soil between rows of plants, set with their narrow necks protruding just above the surface. When filled with water these containers “sweated” moisture through their porous earthen sides, directly irrigating the roots of the vegetation. Condensing jars, removed from exposure to sun and air, effectively conserved water by protecting it from evaporation.
Aerated water was often employed to cool garden structures. Forcing water under high pressure through miniature openings or thin slots would suspend fine drops of water in the surrounding air, humidifying it and lowering the temperature. To produce this effect, water would first be pumped into reservoirs on the roof. With gravity pressure, the water would descend through columns pierced with thousands of tiny holes, creating an almost invisible mist that gently cooled the room. Aerated by thousands of tiny misting jets, these garden rooms were a tranquil oasis for the body and mind.
Many advances have been made in green architecture and alternative building. The US Green Building Council has established standards for sustainable buildings. However, these achievements need to be integrated with energy-conserving, sustainable landscapes that create new gardens on a regional scale. New and exciting opportunities lie ahead for the creation of unified garden and architectural forms that not only conserve energy, water, and agricultural lands, but are also works of art and places for spiritual renewal.
The California Medical Facility in Vacaville is the major treatment center for ill and/or dying inmates in the state prison system. In the mid-1980s many inmates were dying of AIDS, often dying alone in their cells. This barely-noticed crisis inspired Nancy Jaicks Alexander and Robert Evans Alexander, FAIA (dec.), working with Father Patrick Leslie (then the Catholic chaplain) to establish the first hospice in an American prison.
A unique aspect of this seventeen-bed hospice is that the hospice volunteers, of which there are forty, are all fellow inmates. Many of the volunteers are serving life sentences for murder with no possibility of parole. They receive weekly ongoing training in hospice care. When a patient is close to death, volunteers sit around the clock in eight-hour vigils so that no man will die alone. The principal fatal diseases at this time are lung cancer, cirrhosis of the liver, and HIV/AIDS.
Students in LA 256: Healing Gardens and Restorative Landscapes, taught by Clare Cooper Marcus, took on the challenge of creating a garden for this hospice. This class was not a studio; rather it was principally a seminar with reading, lectures, discussion, and experiential exercises. The garden design was in lieu of a term paper, and the students had just two weeks to produce their proposals along with suggested budgets. Preliminary designs were reviewed after one week by Associate Professor Louise Mozingo, and landscape architect Vince Healy who, as a student at Harvard, had written his MLA thesis on hospice gardens.
The Dog Run
As a first step, Nancy, Chaplain Keith Knauf (current director of hospice volunteers), and I met with some of the hospice volunteers to solicit their ideas. They talked about the current 35×12-feet outdoor space of the hospice – a concrete slab completely caged-in with chain link – which the staff calls a patio and the inmates term “The Dog Run.” They were enthusiastic about the idea of expanding it and creating a garden.
I asked them what they thought would be important in such a garden. “The sight and sound of water,” said one man. “I grew up near the Southern California coast and the sound of water is really important to me…” “Lots of color,” offered another. “The hospice wing is pretty cheery.” And another suggested, “Things to eat! We have some cherry tomatoes and peppers in the Dog Run. People really like that.”
I asked what might be some of the objections which the administrative or custody (“security”) staff could raise and among the responses was, “It would have to have a roof like the Dog Run so we couldn’t climb out and escape.” Additionally, I was told that, “Chain link would have to be anchored all round in concrete so a person couldn’t tunnel out.” Another informed me, “They wouldn’t allow anything that could be broken apart and used as a weapon.”
As enthusiastic as they were, the inmate-volunteers were well aware that the biggest impediment would be the cost. “But we could do some of the work ourselves,” volunteered one man, “I have a degree in civil engineering from Sacramento State. I could build a fountain.” Another, who had worked in construction, said he could build planter boxes. “We could get local nurseries to donate plants.” “Inmates in the horticulture and landscaping program could raise plants and take on the maintenance,” was the inspired suggestion of another man. The most surprising idea came from a grey-haired, stocky man. “Twice a year we hold food sales. We sell pizza and donuts – stuff like that. We make over $6,000 each time. We could give that money for the garden.”
No Trees Allowed
The prison authorities agreed, after appropriate security checks, to permit the students to tour the prison and measure and photograph the proposed garden site. For all of us it was quite an emotional experience: none of us had been in a prison before, most had never visited a hospice.
Like most prisons, the environment of the California Medical Facility at Vacaville is grim. The building is a quarter mile long and houses 3,300 inmates, of whom 550 are diagnosed with HIV. Within the prison there is no color and little sound beyond men shuffling along the corridor to a clinic appointment, guards calling out to inmates to stand against the wall as visitors pass, and the clanging echoes of security gates opening and closing.
Cell blocks open off a wide concrete corridor like the teeth of a comb. Between the cell blocks are areas of open space, some used for exercise and weight training, others filled with dead grass and inaccessible. On one side of the prison are sports fields used at designated times for running, baseball, basketball, and socializing. Here, some of the inmates feed seagulls with food left over from their lunch. There is no shade; there are no trees. In July 2006, outdoor temperatures reached 108°. A lone tree in a courtyard next to the chapel was once climbed by a patient from the psychiatric unit trying to escape. The tree was cut down and the courtyard permanently closed.
The one bright spot in the whole facility is an area for vocational training in horticulture comprising a garden, greenhouse, lath house, and compost bins. Perhaps the most touching experience in our whole prison tour was entering the shady verdure of the lath house and meeting a slim, white-haired man with deep blue eyes wearing a neat blue work shirt. “Please come in – come in! My name is Richard; just – Richard…” He proudly showed us his domain – gravel paths winding between ferns and tropical plants, each neatly labeled with its Latin and English names. “This was nothing when I came here two years ago – all overgrown, no labels. And I didn’t know anything about plants! Now I have my California State Certificate in Horticulture.” Unfortunately this little oasis in the prison is a quarter mile from the hospice wing and security restrictions do not permit inmate-patients being brought here to enjoy the plants and the garden.
As the students measured and photographed the potential site of a garden for the hospice (under the watchful eyes of guards in a nearby tower), we all become aware of the limitations that would have to be dealt with: a large steel storage container that could not be moved, a driveway for delivery vehicles that could not be transgressed, a security restriction that said, “No trees,” and the requirement that the whole site must be surrounded and “roofed” with chain link fence. Nevertheless, the students saw the potential to create a healing oasis in this otherwise grim environment.
The Most Creative People in California
The last class meeting comprised a return visit to the prison, and formal presentations by the three student teams to prison officials, including the chief medical officer for HIV treatment services, the associate warden, a lieutenant from the custody division, and the director of hospice volunteers. Unfortunately, the inmate-volunteers themselves were not permitted to attend.
Prison officials were impressed with the quality and sensitivity of the designs, as well as the goal of reducing costs by proposing drought tolerant plants and solar panels. The students took note of the requirement that every square inch of the garden should be visible when a guard steps out of the hospice into the open space. They also responded to suggestions from lectures and reading that a hospice garden needs places where a person alone, or a patient and a visitor, can find some privacy; places where a family group might sit comfortably with a chaplain or counselor; raised beds where a patient in a wheelchair might pick tomatoes or water strawberries; opportunities to visually “escape” by viewing the hills beyond the double chain-link and electric fence which surround the entire prison. The prison authorities were also pleased to note that student-teams recognized the potential for horticulture trainees to raise cuttings and annuals and plant up beds in the hospice gardens, thus linking these two elements of the prison population.
All the designs recognized the essentials of a healing or restorative landscape in a healthcare environment, whether in a hospice, a hospital, or a nursing home: seasonal color, intricacy of texture, the sight and sound of water, close in and distant views, plants that move with the slightest breeze, flowers to attract wildlife (the restrictions of the chain link fence would restrict this to hummingbirds and butterflies). The goal is to create a rich, sensory milieu since empirical evidence shows that “nature distraction” has the affect of reducing stress, lowering blood pressure, and reducing the heart rate.
A few design elements were vetoed by the head of security. We had urged the students to propose quick-growing vines that could withstand the summer temperatures of 100°-plus in Vacaville and that would soften the effect of the required chain-link “cage” around and over the garden. Too late, we discovered that prison security goes the rounds, shaking every piece of chain-link three times a day in case they are being filed through prior to an escape attempt. The one team who proposed a split bamboo fence inside, and separate from, the chain link got the green light. Irrigation systems, proposed by two teams, were also vetoed in case inmates dug them up and “re-used” the metal couplings. A final surprise veto came for four lemon trees in large pots. At first we thought it was for the pots; we had been told to avoid anything that could be broken and used as a weapon. But it was for the lemon trees. “They’ll take the fruit and make it into alcohol. There are stills in the prison. We don’t know where they are. They’ll use anything – raisins from the cafeteria, fruit brought in by visitors.” On recounting this to colleague Randy Hester, he remarked, “It sounds like some of the most creative people in California are in prison!”
An Island of Compassion
At the end of the presentations, prison officials were very enthusiastic about creating the garden and were, I think, totally persuaded as to its potential psychological benefits for staff, inmate-patients, inmate-volunteers, and visitors. They were delighted that we could leave copies of all the designs with them, to use in any way they wanted. The problem of actually creating a garden, as always, is money. The prison system budget is hugely over-stretched; crowding has resulted in indoor gymnasia and recreational facilities being converted into dormitories. “We cannot use taxpayers’ money to make a garden,” we were told by Dr. Bick. “But five years ago, they told me I couldn’t have a new clinic, and this year it opened. We’ll create that garden somehow, however long it takes!”
Nancy refers to the hospice that she helped to create as “an island of compassion in a sea of violence, fear, and paranoia.” We are hopeful that the garden, when it is created, will become a restorative oasis for those who are dying, for the medical staff, and for the inmate-volunteers who care for their peers.
About the Author
Clare Cooper Marcus is Professor Emerita in the Departments of Architecture and Landscape Architecture at the University of California, Berkeley. She is the Principal of Healing Landscapes, a consulting firm that specializes in researching the effectiveness of restorative landscapes in healthcare settings. She is internationally recognized for her research on the social and psychological implications of design, particularly urban open space, affordable housing, outdoor space in healthcare, and environments for children and the elderly.