Monday, March 3, 2014
8 1 Eco city plans for sustainability
8.1 Eco-city plans: for sustainability
Sustain derives from sub- [under] and tenere [hold]. It means to hold under, and thus keep up, as in "a sustained musical note. Environmentally, a sustainable
city is one that can keep going because it uses resources economically, avoids waste, recycles where possible and adopts policies that bear fruit in the
long term. Forestry is the oldest and best example of sustainable planning. Von Carlowitz, in 1713, explained that if forests were not planned on a sustainable
basis, humanity would plunge into poverty and destitution, as was happening in Central Europe at that time (Speidel, 1984). Foresters aim at the highest
timber yield that can be sustained. If the periodic harvest matches incremental growth, equilibrium will be maintained.
The Bruntland Commission, in 1987, defined sustainable development as "development that meets the needs of the present without compromising the ability
of future generations to meet their own needs (Bruntland, 1987). This definition is often quoted verbatim, possibly because its meaning is so hazy. What
is "development? Do the "needs of the present include two cars and two homes for each family? Who knows the needs of future generations? Even forestry
is not sustainable development within the Bruntland definition, because forests cannot be developed to meet "the needs of the present. Then again, if
future generations take our advice about recycling, new timber reserves will hardly be necessary. Nor will they be required if current moves towards the
silicon office, the Internet book and the fibre optic data highway come to fruition. For all these reasons, I
Fig 8.1 Sustainable cities should have fewer inputs and fewer outputs, because they recycle (materials, energy, water, dust etc)
prefer Eco-city to Sustainable City. Eco- means home. Eco-city means "home city, implying that a whole city can be looked after as wisely as a private
house, economically and with cupboards for old pieces of string and empty jamjars. Modernist cities have high inputs and high outputs (Figure 8.1). Eco-city
planners should aim to produce cities with lower inputs of energy and materials, with lower outputs of waste and pollution.
Despite the merits of the foresters conception of sustainability, it remains far from perfect. Modern scientific forestry, which originated in nineteenth
century Germany, was aimed at producing a sustainable high yield of timber. But the technique depended on the exclusion of sporting and aesthetic interests
from forest management. After 1919, British foresters followed the German example, as did Indian, American and other foresters. Factory methods came to
dominate forest practice. In ancient times, forests had been maintained for timber, fuel, hunting, grazing and the gathering of wild food. It has been
a great struggle to re-introduce other objectives back into forest management, and doing so has diminished the "sustainable yield of timber.
Fig 8.2 If they take all the advice which is given, there is a danger of sustainable cities being totally joyless.
Cities, too, must be planned for multiple objectives. Sustainability is but one amongst many goals. We also want cities that are beautiful, convenient,
comfortable and accessible. If sustainability were overemphasized, which is not very likely, cities would become miserable places. Residential densities
would be high. Personal space would be restricted. Everyone would live in walk-up apartment blocks with flat roofs. Roofspace would be used to grow vegetables,
irrigated by drip-fed sewage effluent. Most people would walk or cycle to work (Figure 2). Definitely, there would be no golf courses. Walls would be thick,
windows small, streets narrow, all to conserve energy. Much less food would be cooked and much less protein eaten. As Charles Correa puts it, in The New
Landscape: Urbanization in the Third World:
If we look at all the fashionable concerns of environmentalists today -- balanced ecosystems, recycling of waste products, appropriate lifestyles, indigenous
technology -- we find that the people of the Third World already have it all. (Correa,1989)
There is a good case for making technology transfer a two-way process, but few inhabitants of the worlds prosperous cities wish to be "levelled down to
the condition of Third World cities. This essay is about some of the things that can be done by physical planning to make cities more sustainable without
losing sight of other urban objectives. If one were making a physical model of a city, the five chief elements would be: landform, water, vegetation, transport
and buildings. Let us consider them in turn.
NASA photography showed us Earths fragility
8.2 Landform plans
Modern cities are on the move. The cycle of construction and reconstruction has become perpetual and may accelerate. Vast quantities of earth, rock and
building rubble are shifted about. Waste material is excavated to make foundations. Tunnels are dug for transport and infrastructure. Sand and gravel deposits
are quarried to make concrete and to obtain fill for embankments. Home improvements lead to skips in every street. Demolition of old buildings yields enormous
quantities of rubble. Where should these wastes go? One solution is to place them in the clay, sand, gravel and rock quarries that are excavated when cities
are built. Quarries and pits surround modern cities, but filling them has drawbacks. First, quarries are not likely to be near the city centres where most
demolition and construction take place. Second, pits tend to be in low-lying land, where there is a danger of polluting groundwater reserves. Third, it
seems a wretchedly unimaginative policy.
The eco-city solution is to prepare a landform plan, statutory or non-statutory, showing areas where new hills, valleys, plains and lakes are possible,
desirable and undesirable (Figure 8.3). The plan should also mark areas where waste materials can be stored for recycling. Most cities have large areas
of land that, for one reason or another, are unused and await redevelopment. They should become temporary stockpiles of sand, gravel, clay, rock, demolition
rubble, metal, timber, topsoil, garden waste and other materials, equivalent to the area behind your garden shed. At the town scale, areas for new hills,
lakes and valleys should be marked. Often, they will be on the urban fringe, where the city is expanding. Such land can be made into wondrous new landscapes.
All we need is imagination, and plans. Demolition material should not be removed from building sites unless it can be shown that it will be put to good
use elsewhere. This principle should be written into urban landscape plans.
Fig 8.3 Urban landform plans should show where change is (1) possible (2) desirable (3) undesirable
8.3 Water Plans
Great cities should be designed to accumulate water, as they do knowledge and gold - and the water should be recycled within city boundaries.
Roman Aqueduct (in Istanbul)
Roman Cistern (in Istanbul)
In the Roman Empire, fresh water was brought in by aqueduct and dirty water was discharged into streams, which became sewers, and then into the Tiber via
the cloaca maxima. The Roman approach to water management remained the only possibility until modern times. Now, we can extract water from the foulest
rivers and purify it for household use. We can also afford to lay different pipes for the supply and disposal of different types of water: roofwater, roadwater,
sewage water (without solids). The water types can be described as bluewater, greywater and brownwater. Each should be used in a different way. Bluewater
should be infiltrated where it falls. Greywater may have to be filtered to remove hydrocarbons. Brownwater should be treated in reedbeds or by conventional
The new approach to water management has profound consequences for physical planning. Roofs should be designed to detain and evaporate water. Parks should
have reed beds, storm detention ponds and infiltration ponds. Gardens should have large tanks, as they used to in the old days, to store rainwater and
to supply water features. Cities should have more trees. Pedestrian surfaces should be porous, so that they do not produce surface water runoff. Urban
valleys should be designed so that they can flood. New buildings in flood plains should be floodable. All buildings should be designed with rainwater storage
and infiltration capacity, on the roof or in the grounds.
8.4 Vegetation plans
Medieval cities had little vegetation, because land within city walls was so scarce and
Central Edinburgh in 1830
Fig 8.4a Central Edinburgh in 1830 - with few trees
Central Edinburgh in 1990
Fig 8.4b Central Edinburgh in 1990 - with many more trees
so expensive. As artillery improved and the practice of siege warfare declined, private gardens and public parks became thinkable. In the nineteenth century
they became popular, as did coal fires. The latter transformed rain into dilute sulphuric acid, which dissolved all but the toughest vegetation. There
was also a shortage of firewood, which put trees at risk. It was only in the twentieth century that cities became richly vegetated. This process can be
seen in the illustrations of Edinburgh (Figure 8.4a and 8.4b). My guess is that if another photograph is taken in AD 2050, the process will have gone further.
As it was the public park and the private garden that created space for ornamental vegetation in cities, the vegetation was managed in a gardenesque way.
It was not countryside. Park managers aimed for three categories of vegetation: clear-stemmed trees, mown grass and ornamental beds. From a sustainability
viewpoint, this was improvident. Heavy resource inputs are required for park maintenance, as fuel, fertilizer, pesticide, herbicide and irrigation. These
inputs produce wastes: air pollution, soil pollution, water pollution and noise pollution. They also destroy wildlife habitats. Is it possible to strike
a compromise between garden exotica and nature conservation? Yes. Small areas of garden, maintained by hand with loving care, are a delightful luxury.
Large areas of semi-natural habitat, maintained by adaptations of natural processes, provide a good environment for man. But it is time to do away with
the middle landscape of "amenity grass and "amenity shrubs, where the "amenity in question is gardenesque in the sense of "like a garden.
A plan for creating new habitats in Holland
Instead, we should create networks of natural habitats extending from country to city. Holland, which is a densely populated land with little natural vegetation,
is very advanced in this respect. They have four strategies for developing habitat networks in the Green Heart of the Ring City. Each is named after an
animal that would benefit from the strategy (Figure 8.5). "Godwit is a plan for restoring variety to existing grassland ecosystems. "Otter is a plan
for using corridors to improve the dispersal of habitats, especially open water and marshland. "Elk is a plan for segregated habitats, such as wooded
marshes. "Harrier is a plan to create an optimal variety of ecosystems in reed, sedge and tidal areas (Lankhorst, 1994).
Food production in cities should also become the norm. This will enable life in the city to be sustained. Salad crops can be grown on flat roofs. Fruit
and nuts can be collected from public orchards. Vegetables can be grown in the space around houses. Fish can be caught in reservoirs. Mushrooms can be
grown in cellars. Producing these goods can be a leisure-time pursuit. It is known as permaculture, which is an abbreviation of permanent agriculture (Mollison,
1988). The idea has achieved cult status among environmental design students, if not yet among the general population. The aim is to model food production
on self-sustaining natural ecosystems. Sunlight is the energy source, materials are recycled, synergy is encouraged. For example:
Chickens, as domesticated forest fowl, are at their best in forest-like environments, such as orchards. An orchard to them is a supermarket, where they
can help themselves to basic needs such as water, shelter, shade, dust and grit, and moreover, they feed on pest insects and weed seeds and turn those
into manure. (de Waard, 1994)
By these means, one plus one makes three. Permaculture can work in small urban gardens, where it sometimes goes under the name "edible landscaping. It
makes cities more productive and therefore more sustainable, as the Russians found after the collapse of communism.
8.5 Green Transport Plans
Red commuting, in Paris
Red commuting, in Paris
Green commuting, in Berlin
Green commuting, in Berlin
Red commuters takes their name from the red eyes, the blood and the environmental balance sheet which is reddened by commuting in private cars. Red commuters
inflict many injuries on themselves and others, while the cities they inhabit are made less sustainable. Green commuters travel on foot, bicycle, roller
skates, or whatever, without imposing social costs on cities. Such behaviour needs to be encouraged. It saves energy. It avoids pollution. It makes cities
more sustainable. A 1 mile walk to work needs only the energy supplied by one slice of toast, without butter or marmalade. Travelling the same distance
by car takes energy equivalent to 40 slices of toast for propulsion alone. By train, it takes 17 slices. Green soap powder is widely available. Green commuting
is not. Red commuters hold all the trumps, at present. Each year they have more cars, more roadspace, more places to park their vehicles. Billions are
spent on new bridges, tunnels, junctions and bypasses, which move bottlenecks but rarely cure them. Part of the reason for the reds claim on the public
purse is that roads are also used for the transport of essential goods. Car commuters are interlopers.
In most cities, green commuters are a neglected underclass, grateful for the odd bean chucked in their direction, but always yearning for a wholesome meal.
When pedestrian bridges are built, they usually remove an inconvenience from road users, and make the pedestrian walk further. When cycle routes are planned,
they usually go beside busy roads, or through bumpy back streets which make the cyclist peddle further. Carrots and sticks should be used to encourage
green commuting. Road pricing, restrictions on access and limitations on car parking can be used as sticks. But after years of chewing old bones, green
commuters dream of carrots.
The first Great Carrot would be a network of direct and environmentally pleasant routeways. It should be conceived as a second public realm. The first public
realm, of vehicular roadspace, is as old as the wheel. Some roads are suitable for joint use by vehicles and pedestrians. Much depends on traffic flow.
If a road has 500 vehicle movements per day, it can be reasonably pleasant for pedestrians. If there are 5000 movements per day, it not pleasant. If there
are 50@t000 movements per day, it is intolerable. For a really enjoyable walk to work, one does not want to be a second-class citizen on the edge of a
road, subject to noise and fumes. Green commuters need a safe realm of pedestrianized public space. It should extend through parks, beside rivers, across
urban squares and along pedestrian streets.
The second Great Carrot would be a network of cycle routes. Too many wives drive their husbands to the station and an earlier grave. Surely, ten minutes
of useful exercise is better than ten wasted minutes on an exercise machine. Trains are more punctual than buses, and a cycle ride followed by a train
journey and a short walk can be pleasanter than time spent in red commuting, and faster. If one has catch a bus to catch a train to catch a bus, then over
30 minutes have to be allowed for missed connections. Depending on traffic volumes, cycle routes can be shared with pedestrians or motor vehicles or both.
As few of us are willing to cycle or walk more than 30 minutes, green routes should be planned in conjunction with bus and train routes.
The bicycle works best as a feeder system for bus and rail transport systems, which are most economic in high-volume corridors. This requires excellent
cycle storage facilities at bus and rail stations. Trains need high passenger volumes to be economic. Buses also need high passenger volumes, and are too
slow if they snake about to collect passengers. It can make a bus journey take five times longer than the equivalent car journey. The solution is to plan
commuter transport on a "stars and stripes basis (Figure 6). The stars should be feeder paths for cyclists and pedestrians. The stripes should be linear
bus and train routes. At the centre of each star there should be safe and secure cycle stores, cafes, shops, shelters and delightful gardens in which to
sit to wait. Exotic forms of transport could also be interconnected. In Canada, some commuters travel by ice skate in winter and kayak in summer. In Britain,
long-distance bridleways, and stables, would make it possible for some to commute on horseback. Others could use roller skates, as in Barcelona.
[FIG 8.6 ] Stars of cyclepaths should feed railway stations and bus stops
Eco-cities, with green transport systems, would meet the needs of the young, the old, the poor and the dispossessed. Lonely walks are dangerous. There is
safety in numbers. Well-used walks and traffic interchange points enjoy the benefit of visual policing, and are safe from the danger of drunk drivers,
joyriders and runaway trucks.
Provision for green transport costs money. It should not be done on the cheap. If the percentage of commuters who travel by bicycle is to rise towards 30%,
as it has done in Freiburg (Vidal, 1994), then the allocated proportion of the transport budget should rise in the same ratio. Indeed, after years of neglect,
there is an unchallengeable case for spending way above the 30% budget for a decade. We should allocate 100% in the first year. Some first-class examples
of beautiful, safe, convenient green transport routes could revolutionize the received wisdom on transport planning and design. At some point we may be
able to have a network of plastic tubes, with blown air assisting cyclists in their direction of travel (Figure 7).
[FIG 8.7 ]
Rail stations should be integrated with cycle networks
8.6 Sustainable buildings
Fig 8.8 Eco-cities may become green hills, with only the pre-twenty-first century quarters having tiled roofs. All the rest will be vegetated
In the past, great cities have been centres of government, military power, trade and manufacturing, which influenced their appearance. Future cities may
have all these roles, but they will be predominantly residential. Fifty years ago, 95% of the worlds population was rural. In fifty years time, 95% may
be urban, certainly in terms of lifestyle, probably in terms of physical character. Mans home may become a low-density sprawl with high-density nodes.
Life in the suburbs of great cities is becoming very similar to life in rural villages and isolated farmsteads. But the city of tomorrow may look very
different from the city of today.
Buildings will be much more vegetated, for a variety of reasons. First, vegetation enables cities to hold more water. Second, it reduces glare. Third, vegetation
takes in carbon dioxide and gives out oxygen. Fourth, it provides food and habitat for wildlife. Fifth, vegetation absorbs noise and prevents reflections
from road to wall to window to roof. Sixth, dust collects on leaves and goes wherever the leaves go, so that particulate air pollution is reduced. Seventh,
vegetation keeps buildings cooler in summer and warmer in winter. Eighth, vegetation on buildings contributes to the permaculture harvest of cities, as
espalier apples have always done. Ninth, people love flowers and greenery. Tenth, the tide of history cannot be held back.
Clad with slates or tiles, roofs can support moss and lichens but not plants with invasive roots. That is why cities used to be made without vegetated roofs.
Today it is comparatively easy to make flat and shallow-pitched roofs that are waterproof and can be vegetated. Concrete, steel and high-strength bricks
also make it easy to build load-bearing structures that can carry the load. In high-density cities, vegetated roofs can provide the quiet and private spaces
that people need for rest and relaxation. The city of tomorrow will certainly look green.
When planners, architects and builders have fully absorbed the reasons for covering structures with leaves, we could see the concrete jungles of today becoming
the greener jungles of tomorrow. There may have to be Tiled Roof Conservation Zones, where grass roofs are not permitted, and Brick Wall Conservation Zones,
where climbers are not permitted. In new development areas, opposite regulations may become necessary. Architects will require waivers from building regulations
so that they can put up roofs and walls without vegetation. Eco-cities will be unlike their predecessors. From afar, they may resemble great mounds of
vegetation (Figure 8). Landscape planners will have the opportunity to make sculptured roofscapes, so that cities appear to be verdant hills and valleys.
Streets will become shady routes carved through the undergrowth. Roofs will become mountain tops. People will become ants.