Ar. Shabab Raihan Kabir
B. Arch (Buet), M. Arch (Buet), Miab K-072
Asst Chief Architect, Department Of Architecture, Ministry Of Housing And Public Works

In the history of human civilization, more than half of the world’s population was living in cities in very recent years. The urban population will get in touch with 5 billion – 60 % of the world’s population (UN, 2006) by 2030. The boost in population in urban areas occurs more in developing countries rather than in developed countries. Many cities in the developing world are growing hurriedly due to real population growth, but to a much larger extent due to resettlement from rural areas to the cities, and transformation of rural settlements into cities. The result is an uninhibited urban collapse with increasing human settlements, industrial growth and infrastructure expansion (UN, 2006).

The Consequence of Urban Progression
In spite of this the urban open spaces are shrinking and are becoming less accessible at an alarming rate. The urbanization bonanza and market forces are blind folding us to the reality of the many ways in which the world around us is diminishing and emaciating. As cities are growing at a very faster rate, so the huge open spaces become ever more important for the well being of the urban dwellers (Ken Yeang, 2004). This is, as we experience today, more factual to Dhaka, hundreds of public open spaces of different sizes were either partly or fully mislaid to irregular building structures. Like any other sustainable city, Dhaka needs a huge stock of open spaces for urban services or utilities and circulation besides space needed for different public function and recreational activities (Mowla, 2005 and Rubenstain, 1992). It is identified that for a healthy city we need a right balance and proportion of built-up open spaces (Rubenstain, 1992). It is found that there is a correlation between biomass in an area and it has a soothing effect on the environment and the sustainability (Vroom and Meeus, Eds,1989) of urban open spaces in terms of the pattern of socio-recreational activities in that area (Haysil, 2002).
With this backdrop, it may be said that the prime problem in our urban context is over heating, pollution and water-logging while governing ingredients in the natural environment are open spaces, woods and water bodies and the environmental variables are temperature, relative humidity, air velocity, precipitation, soil-moisture and biomes. An ecosystem is a distinct area in the biosphere, where living and non living things interact within and between each other to produce a sustainable environment (Ken Yeang, 2004). The condition in which an animal or a human being lives along with other species of plants and animals in an area affects its life. In fact outdoor spaces so to say open spaces of any type; spacious-non spacious, spectacular-non spectacular, formal-informal that surround us in our every day situation shape the major part of our lives (Mowla, 2005a).

The image of Dhaka is not derived from its concrete parts like building, roads etc. it is much deeper and more fluid, that is, its people, pattern of spaces and activities therein, the relationship between the living and nonliving part of its environment, time, space and the people. Any space in an urban area outside the buildings constitutes urban open space and the design and management of these spaces are crucial to urban sustainability and image. A common notion is that ecosystem or biodiversity or eco-design is something outside the city boundaries, whereas ‘green open space’, ‘parks’, ‘gardens’ etc are found within (Mowla 2005a).

Economic development with no environmental control leads to an ecological or environmental degradation which adversely affect the quality of life. The growth of Dhaka originated from the convenient location of river transport linkages. Dhaka has a glorious commercial tradition since the beginning of the Christian era and in different periods of the history; the city was stretched due to momentous developments of trade and commerce. From the very beginning of its development, the city got centrality and the highest commercial importance in the eastern part of India. Globally Dhaka has been reputed as the ‘Queen’ of the eastern cities (Dani, 1962). Planned development over different periods, as witnessed in other living cities has not been a characteristic of Dhaka city. What has physically happened in Dhaka throughout its five hundred years known history is not clearly apparent from its existing structure. However, shadows of what it was can be approximately traced from urban art effects and spaces. The growth of Dhaka has brought with its demand for expanded infrastructures to serve the needs of urban residents and visitors. Dhaka City has experienced a long transformation with respect to land uses, functions and importance in the regional context. Physical development of Dhaka was concentrated mainly on the riverfront of Buriganga extending towards the north up to another river Turag. Total layout was rational arising out of convenient infrastructural linkages. Dholai Khal played an important role in transporting goods and traffics throughout the city. Dhaka’s past growth and present urban configuration have been shaped by the city’s relative susceptibility to flooding. The consideration of settlements and use of land have predominantly been influenced by the availability of high grounds, not the trend of major road approaches. The changes of the population dynamics have also called upon internal structure changes within the city, such as changes in the characteristics of different zones, intensification of use of land, change in use, alteration of location for optimum uses and the invasion and succession. As a result, the city has taken somewhat multi-nuclei form with haphazard land use patterns.

As cities grow ever more densely developed, so the remaining green spaces grow ever more important for the well being of the cities’ inhabitants. To create accessible open spaces now mean many structures are to be torn down in different localities. Thus it can be argued, the design of existing green and open spaces- for the most part, urban parks – should receive attention equal to that of the cities’ buildings. However their status is required to be determined first.

Ecology as a technical input into design is essentially a quite straightforward idea, especially when applied to urban situations. It says that everything is related to everything else, therefore, the elements of urban open spaces are to be carefully selected (Mowla,2008). In environmental design, which by definition is design for everyday surroundings, they also constitute the qualitative aspects of the design, as distinct from quantitative functional or technical characteristics. Such qualitative functions have great influence on the degree to which the environment imparts a sense of well-being. The choice of qualitative characteristics when designing for an existing built environment, where there is something clearly to fit to, or to contrast with, is easier than thinking up completely new ideas for new developments (Simonds,1978).

An Organic-Architectonic System
An ecosystem is any spatial part or organizational unit, which includes living organism and non-living substances, interacting to produce and exchange of materials between the living and nonliving parts. Without the sun, nothing would happen on this earth. Its light, its warmth and its power enable plants, animals and human beings to blossom, grow and flourish. Without its light there would be no colors. It provides the energy that keeps everything alive – an unimaginable 4270 billion kilowatt hour every day. So why design something that is incongruent with ‘Nature’? Nature is what we have, not made. It not only produces plants, soil, stone, water, air but also nourishes animals and man.

The tree is an organic-architectonic system consisting of a foundation, the roots, a column, the trunk and a spatial network of branches. In the case of deciduous trees leaves are an additional summer feature, covering the bare winter structure. The biodiversity contributes towards natural and social sustainability, plants and water is the true ingredients (Mowla, 2008). All the earth’s oxygen was and will be produced by plants and trees. Plants consist of up to 95 % water, and man and other animals of up to 60-70 %. Water is in constant metamorphosis and circulation. It is the principle element of natural life, as every living thing on the earth derives from it. There are plain and plump trees, low, squat trees but also bizarrely expressionist and large baroque tree domes. There are narrow slender trees (cypresses, poplars). There are trees that strive steeply upwards and trailing trees. Leaf roofs, tree domes, forest cathedrals, groves. A tree has become involved with a spot on the earth; it has fixed itself there firmly. Here it will stay and grow, it is exposed to every-thing, wind, sun and snow, nesting birds, gnawing roe-deer, carving and sawing men: It is patient and pliant. This is what a designer needs, to organize a space that is functionally responsive (Rubenstein,1992; Mowla, 2008).

A comprehensive (multidisciplinary) approach of planning is needed for stable urban system (Ken Yeang, 2004, Mowla, 2003). The concept of ecosystem and biodiversity in the built environment design has been assessed and inferred that these can be successfully achieved at urban level by using place based environmental policy planning, that is local context and species needs due attention. Instead of confrontation we need cohabitation with nature for sustainable living. Open space are an important element of built environment which provide vibrancy and sustainability to a city. Ecological approach to design and manage these spaces is crucial to the sustainability of urban environment (Mowla, 2005a).

The Environmental Crisis- Need of a Sustainable Open Space
In the hot humid climate of Bangladesh open spaces including water bodies, both natural and man made, are more than an integral part of life and living. They play an important role in the physical and social activities performed by the inhabitants of the city. Green open spaces when articulated with water bodies become visually more attractive and climatically more responsive. Such spaces develop a natural sustainability of the city. Natural sustainability is rooted in retaining existing ecosystem and cultural relevance (Khaleda, 2003).

Like any other sustainable city, Dhaka needs a huge stock of open spaces for urban services or utilities and circulation besides space needed for different public functions and recreational activities. Open green Spaces in the city act like its lungs besides being used as active recreational and leisure areas for its citizens. Circulation areas also, though serving active purposes, provide some breathing spaces to the urbanities. Spaces provided for the utilities also serve some passive needs. We, therefore, must realize that open spaces have a direct impact on the urban environment and general physical, mental and social health of the urban dwellers (Mowla, 2002 b).

Unfortunately, developments within Dhaka city are aimed at accelerating only the direct economic return. Our developer have made the Word “development” synonymous with destruction of environment but it is not so. There will be need for constructions or cutting trees for development activities but that should be done in a planned manner with planned replenishment of the nature to keep the biomass in a balanced state. An appropriate balance of living and nonliving parts of the environment needs to be promoted to maintain a sustainable ecosystem, because a stable urban morphology is always alive (Mowla, 2005a).
Architects seem to think that the important thing is that buildings look ecological. We must consider a large number of environmental factors that concern the architect. When we talk about the environment friendly urban system the following factors should be included (Vestbro, 2002):
w Design for low health risks;
w Design for low energy use;
w Design that do not deplete the bedrocks;
w Designs using local materials ( that do not generate long transport );
w Designs that are well adapted to climate;
w Designs adapted to changes (to avoid destruction and new building when uses change)
w Planning for the long term development of the built environment towards sustainability;
w Design that facilitates neighborly co-operation around environmental tasks;
w Designs that look environment friendly (to stimulate ecological thinking).

The first four factors do not require any further explanations. The problem is mainly to find out exactly which designs that provides for good health, little use of energy etc. In order to depletion of bedrock, all kinds’ metals should be avoided, but if constructions are such that metal components can be recycled, then of course this renewable material can be used. In addition, building materials that use a lot of energy for its productions, such as cement, should be avoided, unless construction elements can easily be dismantled and reused. For this purpose, new construction techniques are required, e.g. disconnectable joints between construction elements (Holmstrom, 1997).
Quantitative indicator of open space situation
The natural features, lush green spaces and water bodies surrounding the habitations that once made James Taylor write after his visit of 1824, “Dhaka looks like the Venice of the orient”, are no longer there. While comparing Dhaka and Calcutta cities, Prof. N. Islam wrote, “Calcutta has more parks, open spaces, trees and these are better maintained. Most of its ponds and other water bodies are also better kept”. Lack of consciousness and initiative in terms of ecology, environment and socio-cultural aspects by both public and private sectors has given rise to:
w Rapid decline of open spaces and water bodies
w Speeding up of inaccessibility to the open spaces and water bodies.
The total amount of open spaces including roads, footpaths, parks, play fields, lakes, ponds etc. constitute about 17% -18% of the area of the Dhaka city (Daily Janakantha, March 05, 2002). Over the last 30 years or so the open spaces of Dhaka are fast diminishing. If the present trend continues, of the numbered parks, little open spaces, few trees, ponds and water bodies nothing will be left in Dhaka city. Though the banks of the Buriganga River are heavily built up and devoid of green spaces and most of its tributaries are filled up or encroached by illegal structures, it still has profound impact on the citizens of Dhaka. Many people go there for jogging, leisurely walks and other recreational purposes.

The Challenge and the Goal
The architect does not have a role only for the design of new buildings. In the developed part of the world, most of the buildings are already in place. Here the architect has the new and challenging task to take care of the existing building stock, for instance by taking responsibility for refurbishment, reconstructions and adaptations to the new demands for sustainable development. In quantitative terms, such measures are considerably more important for the environment than the design of new buildings. The most important factor in the list is perhaps the responsibility that the architect/ planner have for the long-term development of built environment. This includes factors such as traffic planning for low emissions, urban topologies that promote compact solutions with high service levels while maintaining green and other spatial qualities, provision for mixed uses and integration of social classes and cultural groups. One important factor for sustainable development is to make plans that facilitate neighbourly co-operation such as collective housing or neighbourhood units with spaces for community cooperation.
Ecological Footprint of an Area
The Ecological Footprint is a resource management tool that measures how much land and water area a human population requires to produce the resources it consumes and to absorb its wastes, taking into account prevailing technology. The sustainability challenge is for us to find ways to experience rewarding lives, within the limits of one planet. The ecological footprint (or eco-footprint for short) is a tool to measure our ecological performance. By measuring the Ecological Footprint of a population (an individual, a city, a nation, or all of humanity) we can assess our overdraft, which helps us manage our ecological assets more carefully. The ecological footprint is a means of measuring and communicating human induced environmental impact upon the planet. The footprint analysis presented in this statement seeks to indicate:
w the area of land, or footprint that examined area would require to sustainably maintain the current life styles of its inhabitants;
w the relative contribution of various activity components to this footprint.
Table below presents the results of the EF study of Ramna Area, Dhaka. The consumption items listed in the table have been influenced primarily by data availability. To accounts for these omissions some assumptions have been made.

Population of Ramna and Surrounding area: 3, 27, 200 (aprox. Number from local level survey)

Ecological Footprint of Ramna and surrounding area (hr per yr): 11014.32 (ha per capita/yr): 0.0336

(Data Source: BSS, BEC, DCC, RAJUK, RHD, LGED, BRTA, DTCB, DMP, STP, BANGLADESH COUNTRY REPORT, WASA, DESA, HABITAT COMMITTEE, MINISTRY OF HOUSING AND PUBLIC WORKS, ECONOMIC REPORT OF BANGLADESH, WORLD BANK REPORT 2003)

Key Findings
w This study estimates that the area of land required to sustainability support the population of Ramna at current consumption rates to be 11014.32 hectares of productive land.
w The average Ramna footprint is 0.0336 ha.
w Each Ramna resident uses more than 0.033 hectares.
B. Distribution of Impacts by Category
An analysis by category of impacts shows the highest impact category to be ‘materials and waste’ followed by ‘food, land and wood’, ‘transport and others’ and then ‘utilities’-see figure below.
Distribution of Impacts by components:
Figure below shows the distribution of impacts by component-ordered in terms of the size of impact. It can be seen that the largest 3 impacts are waste (commercial and household) and road. Note that for comparative purposes, no double counting adjustments have been made in the figure bar chart.

EF is a means of simply measuring, monitoring and communicating the environmental dimension of sustainable development. It indicates the relative size of Ramna’s impact on the environment and how far the city needs to go to achieve ecological sustainability. Footprint analysis similar to that presented here has been used to formulate sustainability targets, inform decision-making, for education and public awareness purposes. The EF analysis can also provide a frame work for future data gathering exercises.
Discussions and Recommendations
01. Open space are an important element of built environment which provide vibrancy and sustainability to a city. The unplanned encroachments and promulgation of built forms contribute to deforestation, water logging, flooding, overheating, pollution of water, soil and air etc. The prime problem in our urban context is over heating, pollution and water logging while governing ingredients in the natural environment are open spaces, woods and water bodies and the environmental variables are temperature, relative humidity, air velocity, precipitation, soil-moisture and biomes. Looking at the global economy today, one has to be increasingly aware of energy as a scarce resource; the need for architects to design for a sustainable future becomes a self-evident imperative. The available open spaces are, therefore, required to be organized judiciously to maximize its response. Biodiversity of place and contextual response in open space design and management has a bearing on the comfort feeling of the users. Ecological footprint and the theory of partition matrix as discussed therefore used in this study as the yardstick for analysis to achieve these goals.
02. Dhaka City has experienced a long transformation with respect to land uses, functions and importance in the regional context. The city has taken somewhat multi-nuclei form with haphazard land use patterns. The variation in shape, size, layout, treatment, and development of urban open spaces is an offshoot of physical, socio-cultural, political and economic factors. Ramna as an open space in this city starts during Mughal rule. Dhaka requires at least 20% of its area as open space, whereas, at present the percentage of open space of DCC is 9 to 10%. Local planning experts suggest at least 1 acre of parks and open spaces per 1000 population for cities of Bangladesh. It suggests that natural vegetation is the primary and sometimes last representative of nature in the city and that vegetation contributes to the sense of place. Open space must be considered as a public good when attempts to measure its value are made. Open green Spaces in the city act like its lungs besides being used as active recreational and leisure areas for its citizens.

03. Dhaka is now a mega city of over 10 million people. The average growth rate has decreased from 7% to 2% but the urbanization rate has exceeded 6%. In the past the city was clean, the air was fresh to breathe, fewer traffic and the river was the main way to transport and lifeline for attraction and now Ramna is the only major public open space in this city. The geomorphology of the Ramna region is intense. The geomorphological character of the region is defined by the lakes, ponds, green open spaces, and by the dense built form situated at a short distance around the open spaces. The important characteristic of this area is that it is extensively covered by vegetative surfaces and has a distribution of a large number of mature trees. The climate of the Ramna area is characterised as mild Tropical with hot humid features. Wind velocities are high during wet season. Studies have shown that urban parks and green areas in cities can create a cool island, the intensity of which depends on the type and quality of the vegetation. Urban Parks with high and wide canopy trees have the maximum cooling effect during the hottest hours of the day and have a positive effect on human climatic comfort.

04. Open spaces are given little attention and are not at all considered as one of the infrastructure or functional need of a city. At present the land of Ramna is under-utilized (not proper use as city’s open space) by the city dwellers, the condition of present use being substandard, while maintenance is poor. The vegetation pattern in the area decisively plays a responsive role in attracting diversity of people and activity into the area. The ecosystem approach towards qualitative assessment of urban open space at Ramna shows that there is a correlation between converging activities into the area, diversity of vegetation and comfort conditions. The area is becoming shorter and shorter by the unplanned encroachments and fragmented developments; it needs to be conserved for the posterity.