"The Sustainable City" by Christopher Charles Benninger, Architect.

Cities are the engines that pull the economic development train. They are centers of social change, innovation, employment and economic expansion. They sponsor diversity, tolerance and are a refuge from oppression. They are growing faster than planned for and are yielding benefits to their hinterlands and nations. But unplanned, rapid urban growth brings a multitude of stresses on the people and upon the environment.

The Urban Crises of Sustainability
The environment suffers in multiple dimensions as the ground water is exhausted and replenished with polluted waste, poisoning the subterranean strata upon which city rests. Paving over and closing natural earth filters denies even normal recharge into the city’s aquifer systems. The water run-off flushes streams and rivers and carries silt into the their beds, raising water levels and accordingly widening channels, causing erosion on the edges and flooding in storms. Hillsides are encroached upon resulting in the felling of trees, more soil erosion and more silting. Blocking natural drainage networks causes flooding and the destruction of natural habitats. The general biomass is depleted as roads, buildings, parking lots and paved grounds replace biomass carpeted areas. Natural migration corridors of fauna are destroyed, breeding and gathering places of birds disappear and the ecological balance is lost. Waste water is not filtered, or re-charged, into the eco-system and is dumped untreated within rivers, ponds, lakes and streams. Along with toxic sewerage dumping, chemical wastes from industry destroy natural life in water bodies turning them into stagnant, toxic breeding cultures for a myriad of micro-organisms whose impact is life threatening. This is all compounded by building on river edges, making roads within riverbeds, felling trees indiscriminately and is exasperated by air pollution. The toxic air pollutants emitted by building construction sites, building operations, vehicles and machines cover our human settlements with a haze of poisonous gasses. Respiratory diseases and chemically catalyzed cancers are some of the tragedies breed by our new city ecology.


Green City Design
If the human race is to survive and flourish it must address this crisis at the individual level, household level, community level and the city level. Herein comes the issue of urban planning and urban design. The Principles of Intelligent Urbanism is a set of ten axioms for urban planning, around which issues can be debated. It provides an integrated method of addressing all urban issues as a factor of the others. Balance with Nature is an axiom of the PIU that specifically lays out areas where city building connects with environmental degradation. PIU principles Balance with Tradition and Balance with Efficiency bring heritage assets and infrastructure onto the same page as urban environment. Without a charter of principles to begin with, talking about sustainable urban design will lead nowhere.

The Essential Planning and Design Actions:
Urban design must employ several essential strategies to turn the tide of the dying city. Green cities are achievable! Buildings, vehicles, waste and drainage systems, energy consumption, paved areas and machines are culprits that must be addressed simultaneously.

Protecting water bodies is essential. First all dumping sewerage and industrial waste disposal into water bodies must be stopped and alternative waste methods employed. Many of these waste processing technologies generate composts and valuable organic fertilizers. Second building within, or next to, water bodies must be stopped in its tracts! This means no roads in rivers! This means a “no build” set-back from all water bodies and restrictions on all paved and built-over activity. A ninety-nine year notice must be issued to all buildings located within water front ecologically fragile set-backs. Such encroachments must be phased out and demolished. The land owners must be compensated within land pooling and TDR schemes. They can be given a tax holiday on municipal taxes to defray their losses.

Protecting hill slopes is essential : As building on the slopes increases the percentage of areas covered by paving and buildings increases. There must be a proportional reduction in building and paving pressure as the slopes increase. This would be reflected in FSI’s allowed and in percentages of roads and other paved areas allowed over land on slopes, which would both reduce as the slopes increase.

Mass public transport is essential: Countering the mechanized vehicle is essential. It is both a source of fatal accidents and air and noise pollution. There are multiple alternatives to driving privately owned vehicles between origins and destinations. Public mass transport must happen through a variety of modes, such as underground rail, raised rail, rapid buss networks, midi-bus loops, rickshaw zones and pedestrian corridors. Mass transit that moves large numbers of people safely along high density corridors is the only solution. There must be a hierarchical network of mass transport systems, each over-laying the other and meeting at nodes of modal split. These modal split nodes are where different types of transport share termini and stations. An express bus loop may over-lap a raised metro train; or a midi-bus network may overlap a RBT loop. Cycle and pedestrian pathways may over-lap midi-bus bus networks! These templates and tiers must be shifted and adjusted to fit each human settlement’s potentials and constraints.

Creating integrated open space systems is essential : The planning of inter-locked open space networks balances nature and allows pedestrian and cycle movement within the confines and safety of the enclosed corridors. Open spaces will straddle water bodies and reach up hills along the natural drainage streams. The open space network of a city will mirror the natural drainage system, and include larger recreational and environmental reserves. As the hill slopes surrounding cities increase in slope the densities allowed reduce to zero and the hill tops become urban nature reserves. Even relatively level cities in South India have ancient, inter-locked terraced ponds and channels wherein the slightly higher ones feed the successively lower ones.

Creating the pedestrian realm is essential : Walkable towns and cities is a very “do-able” goal. The number of European examples is endless and the joy of visiting them is immeasurable. Pedestrian corridors can link into points of modal split and synchronize with the mass transport network. These links are the life arteries that tie together open spaces and heritage areas. Parking decals must be sold to citizens who park in the dense, narrow lane precincts of the city core. The price of decals must represent an annual rent for the market value of the space covered by the vehicle. Stricter regulations regarding vehicular entry within center city, high density areas must be created, including the sale of annual entry passes. Paris has recently introduced a bicycle system wherein users have swipe cards to unlock and ride cycles. The first hour is free, and nominal charges are applied to longer usage. Each bicycle is “tracked” in the computer system telling from where it was picked and where dropped and when racks approach being full a van collects and redistributes bicycles. Bicycles and walking corridors can be inter-meshed and integrated with open space and water-front systems.

Greening cities is essential : “Greening Cities” is an excellent strategy for reducing ambient temperatures, cutting air pollution and recharging air. Road- side; river- side; pond-side; stream-side; boundary-side and park planting are all measures to increase the sustainability of cities at very little cost. Urban forests and roof top gardens and agriculture are feasible components of an ecologically sound city. Simple technology exists to transform roof surfaces into gardens that also provide significant insulation from heat gain, reducing the energy consumed for air cooling.

Micro-Energy Systems are essential: Energy generation within cities can be sustainable. Each building site can generate significant savings through solar water heating. Three to five percent of the buildings’ energy requirements can be generated on site through photovoltaic or small wind powered generators. Another twenty percent of a city’s energy needs can be generated within the city limits via wind energy. By the use of sun light reflectors bringing light deep within the building envelopes another two percent of energy can be saved. Just the use of low energy luminaries can save three percent of a city’s energy requirements. Reflective paints on the roof tops of existing structures can save ten percent of the cooling costs of the floor beneath the roof!

Linking a green tax to the sustainable performance of buildings is essential: Buildings alone account for more than fifty percent of energy requirements and pollution in cities. The India Green Cities Movement is promoting green buildings along the lines of the American LEED ratings system. The Tata Energy Research Institute has promoted TERI standards for sustainable architecture. These approaches result in the recycling of water, on-site sewerage processing, cutting power consumption for water heating, lighting and air-conditioning, reducing heat gain in buildings and employing low energy technologies. Any structure on a plot admeasuring 2,000 square meters, or more must be a TERI accredited Green Building, or equivalent. A scaled system of municipal taxes must be applied to compensate the city for environmental offenders, applying higher taxes as the structure gets less green points.


Recycling water is essential: Recycling all types of water used, whether within a house, a building, a neighborhood or a city is a feasible manner of saving water. Numerous technologies for water recharging exist and many cities require new buildings to recharge their individual sites. Cities are composed of micro-watersheds just as rural areas are, and the principles of watershed management must be applied to cities and villages alike. Water management begins from the highest areas with contour bunding, planting along bunded contours, stream bunding, small catchment peculation tanks and lift irrigation. It moves on to water storage cisterns in private plots and neighborhood recharging systems.

Sustaining a diverse animal population in cities is essential: Attracting fauna back to cities can be done through the promotion of all of the measures noted above. Roof top bee hives, protected bird mating and nesting areas, restoring river-side habitats and making water clean enough for fish and water life is essential to create a balanced ecology in cities.

Creating Green Citizens is essential: Green Education is essential for creating good citizens. At all levels of education, knowledge of ecology, sustainability, conservation of non-renewable resources, environment and green measures must be a part of the educational curriculum. Every school child must be sensitive to the issues, the problems and the range of possible solutions, if some day we are to have truly green cities. Each company and public institution must have a green vision statement promoting a “green corporate culture.” The management of wastes and energy and the recycling of water can easily be improved through participation.

About one hundred years ago the Garden Cities Movement was initiated by Ebenezer Howard. No doubt it was naive, elitist and conceptual. But it sparked imaginations about the future of green cities. Patrick Geddes, a micro-biologist and community sociologist made plans for greening and cleaning towns such as Thane. Howard’s idea was to make cities into gardens and parks where people just happened to live. Geddes’s concept was to involve people in the cleaning of ponds and streams, by linking them to religious festivals and community celebrations. Frank Lloyd Wright’s Broadacres City was a utopian model based on America’s vast open areas and city based agriculture. Le Corbusier’s Radiant City envisioned the employment of high-rise construction to free vast tracts of ground areas for recreation, parks and forests and he either lowered mass transport arteries below eyesight into the landscape with pedestrian over-bridges, or raised the roads up so that pedestrians and cyclists could freely move about under them in vast parks.

The new capital city of Bhutan plan for Thimphu, designed on the Principles of Intelligent Urbanism, strives to protect nature, and the people who live within the city. More than fifty percent of land is protected as orchard, stream and river side, open space, ecological conservation and hill slope lands. In the late nineteenth century great public urban parks and gardens were created.

Cities are people. Cities can be no better than the people who live in them! The Thimphu plan is an experiment and there are many that object to it and put their personal fortunes above that of society. We have ample models and information upon which to build a Green City model and apply that model as relevant to our growing, contemporary cities.

*Professor Christopher Charles Benninger has taught at the Graduate School of Design [Harvard University], is a Distinguished Professor at CEPT [Ahmedabad] and on the Governing Council of the School of Planning and Architecture [New Delhi]. He studied urban planning at MIT and has advised the World Bank, Asian Development Bank, United Nations Centre for Human Settlements, the Planning Commission, HUDCO, the National Housing Bank and numerous urban development authorities. His new capital plan for Thimphu, Bhutan presented him an opportunity to employ his Principles of Intelligent Urbanism, which have been evolved from his work in India, Sri Lanka, Malaysia and Indonesia. He is on the board of editors of CITIES [UK] and his articles on urbanism appear in Ekistics [Greece], Habitat International and numerous other journals. Note: all rights are reserved by the author. 1425 words. 23-11-08