Urban Morphological Change Analysis of Dhaka City, Bangladesh, Using Space Syntax

This article is based on a study of the morphological changes of Dhaka City, the capital of Bangladesh. The main objective of the research is to study the transformation of urban morphology in Dhaka City from 1947 to 2007. Three sample wards (18, 19 and 72) of Dhaka City Corporation are strategically selected as the study areas. Ward 72 has an indigenous type of organic settlement, whereas ward 19 is a planned area, and ward 18 represents a mixed (both planned and informal) type of settlement. In this research, the transformation of urban settlement pattern is examined through space syntax. The results show that the organic settlements (ward 72) are highly integrated both in terms of the local and global syntactic measures (lowest standard deviation for local and global integration, with the highest intelligibility values), and are more connectivity. The scenario is opposite in the case of planned settlements. The characteristics of mixed areas (ward 18) lie in between the organic and planned settlements. Therefore, in summary, it can be stated that the integration, connectivity and intelligibility measures of Dhaka City are found to be high, medium and low for the indigenous, mixed and planned settlement types; respectively

Designing a Blue-Green Infrastructure (BGI) Network: Toward Water-Sensitive Urban Growth Planning in Dhaka, Bangladesh

In a warming world, urban environmental stresses are exacerbated by population-increase-induced development of grey infrastructure that usually leaves minimal scope for blue (and green) elements and processes, potentially resulting in mismanagement of stormwater and flooding issues. This paper explores how urban growth planning in the megacity of Dhaka, Bangladesh can be guided by a blue-green infrastructure (BGI) network that combines blue, green, and grey elements together to provide a multifunctional urban form. We take a three-step approach: First, we analyze the existing spatial morphology to understand potential locations of development and challenges, as well as the types of solutions necessary for water management in different typologies of urban densities. Next, we analyze existing and potential blue and green network locations. Finally, we propose the structural framework for a BGI network at both macro and micro scales. The proposed network takes different forms at different scales and locations and offers different types of flood control and stormwater management options. These can provide directions on Dhaka’s future urban consolidation and expansion with a balance of man-made and natural elements and enable environmental, social, spatial, financial, and governance benefits. The paper concludes with some practical implications and challenges for implementing BGI in Dhaka

The evaulative image of designed open spaces : social use, aesthetic response, and morphological configuration

Urban plazas and public open spaces play significant roles in the creation of livable cities. The aesthetic and morphological dimensions of public spaces are among the essential visual and physical characteristics that need to be understood for successful social use. A literature review revealed gaps in the theory of how the physical attributes, architectural features and morphological characteristics of the built environment enhance the aesthetic response and social interaction in designed public open spaces. This research sets out to articulate the relationship between physical, visual and morphological characteristics of the built environment of urban plazas and public open spaces that can create interactive social relations. By using a mixed-method approach involving both qualitative and quantitative methods, this research addresses both the subjective and objective attributes that can influence users’ aesthetic response and social use. The overall study was conducted in two stages. The use of photo-simulation in a preliminary study explored naturalistic inquiry to identify the most important aesthetically and socially preferred physical characteristics of designed urban open spaces from respondents’ viewpoint. Based on their detailed responses and existing research literature, a list of the salient physical and visual attributes of designed urban open spaces important to preference is developed. To objectively identify the relationship between the research constructs, eight designed urban open spaces of Dhaka, Bangladesh were selected and the main study involved 280 respondents. By using morphological (Space Syntax) and statistical analysis (ANOVA, Factor Analysis), this research seeks to examine the levels of association between aesthetic response, social use, physical attributes and morphological configurations of designed urban open spaces. The research concludes that the frequency of using urban open space is largely influenced by the morphological configuration of the urban structure. Aesthetic qualities are an additional, rather than a primary property of social interaction in the studied urban spaces. This study proposes a visualization model that illustrates the relationship between the research constructs for the future design of urban plazas and paved public open spaces. Abstrac

Emerging green spaces in North of Dhaka: suitability analysis in a dense urban settlement

Dhaka, the capital of Bangladesh, is acute of green spaces. The uncontrolled urban sprawl is encroaching the lands in the city. The Southern part of Dhaka, the oldest part, offers few large urban green spaces for cultural activity, recreation etc. But there is serious deficiency of neighbourhood and regional urban green open or public gathering space in Northern Dhaka, except the diplomatic zone. Hence, this paper aims to identify the potential lands that can be converted into urban green space by using spatial suitability analysis and GIS. Two aspects have been chosen for desired environmental quality: existing criteria and green indices. The suitability factors are as such: size, accessibility, buffer, Historic-cultural value, existing land use, density, flooding, and water body. These suitability factors are classified into four sets- high, moderate, low and no suitability. The findings assist to synthesize the appropriate land to be adapted as public open space in North of Dhaka. Ultimately, it will help to form a base for generating a greener city in the future

Emerging green spaces in North of Dhaka: suitability analysis in a dense urban settlement

Dhaka, the capital of Bangladesh, is acute of green spaces. The uncontrolled urban sprawl is encroaching the lands in the city. The Southern part of Dhaka, the oldest part, offers few large urban green spaces for cultural activity, recreation etc. But there is serious deficiency of neighbourhood and regional urban green open or public gathering space in Northern Dhaka, except the diplomatic zone. Hence, this paper aims to identify the potential lands that can be converted into urban green space by using spatial suitability analysis and GIS. Two aspects have been chosen for desired environmental quality: existing criteria and green indices. The suitability factors are as such: size, accessibility, buffer, Historic-cultural value, existing land use, density, flooding, and water body. These suitability factors are classified into four sets- high, moderate, low and no suitability. The findings assist to synthesize the appropriate land to be adapted as public open space in North of Dhaka. Ultimately, it will help to form a base for generating a greener city in the future

Developing a Strategic Process to Reintroduce a Lost Water Way as a Possible Solution for Water Logging: Case study, An Area of Dhaka Metropolitan City

During the rainy season, Dhaka, the capital city of Bangladesh, faces tremendous rainfall which is annually 1600mm-2000 mm and it is increasing at a rate of 55.90 mm/year. So, in monsoon, some areas of this city suffer from water logging which continues from 3 hours up to two feet to more than one day. It increases the hazards for everyday life for the city dwellers, especially in the transportation and working sectors of the city which follows other socio-economic, health and environmental problem. Dhaka is one of the most populous cities in the world. This area is almost flat and close to sea level. So, Dhaka is susceptible to flood during monsoon. Historically Dhaka has a network of natural canals which was connected to big rivers to serve as a natural drainage system for the rain runoff. These canals served as a good means of transportation also. Gradually, in the course of time this natural drainage system has been almost destroyed. Due to overpopulation, the increasing demand for land and unplanned rapid urbanization causes the destruction and discontinuation of water channels. As a result, waterlogging occurs during the rainy season in various part of the city. Demolition of these water channels and depressions not only affects the natural process of land formation but also alter the ecosystem. This study aims to develop a process to reintroduce a previous waterway in Dhaka city as a possible solution of waterlogging. So, at first, changes in wetlands and water bodies are analyzed through studying the geo-morphological history of Dhaka and ArcGIS analysis to find out the potential water bodies which are needed to be revived or developed further. Hydrological analysis in ArcMap has been done here to show the water flow direction which is derived from the DEM (digital elevation model) of Dhaka city. Then, one disconnecting point is chosen to develop a process for introducing waterway as a possible solution of waterlogging which will also serve as a transportation system. The study only provides a generic idea to verify an idea to resolve the issue of urban waterlogging. The most positive aspect of this proposal is to protect the urban water bodies and convert those as a mean of the transportation system. Without protecting the wetlands and water bodies the drainage system of Dhaka will collapse and inundation will increase. If the method works then, it will be a key factor to make other dead water lines alive for Dhaka City

Developing a Biophilic City through Natural Land Transformation Analysis and Geodesign: The case of Purbachal New Town, Bangladesh

Dhaka, the capital city of Bangladesh is one of the fastest-growing metropolitan regions in the world. To solve the ever-increasing need for housing and to reduce the pressure of the population from the capital city, the Purbachal satellite city was planned. It is the biggest planned township in Bangladesh with an area of over 25 square kilometers. Purbachal is situated at the confluence of the Shitalakhya and Balu rivers. Historically a low-lying wetland, Purbachal has gone through a rapid transformation in past decades. The water bodies around the area have been filled in to create new developable land. Through remote sensing and GIS analysis, this study investigates the transformation of wetland areas in Purbachal New Town. The study Investigates whether the new developments in the Purbachal New Town followed a natural topography or it was drastically modified from its natural conditions. The study also investigates how these changes in the inherent topographical nature of the area can influence the future of the city. The goal of the study is to explore the complex interrelation of different factors responsible for the growth of a city. The main aim is to formulate a realistic city planning process to synthesize systems city approach with the concept of Biophilic design to create spaces where people will be able to live in harmony with nature

Urban Planning as an Extension of War Planning:

War-city relationships had long been studied by scholars regarding wars\u27 sudden impact on cities. Studies typically focused on one specific event\u27s impact on urban military, politics, economy, or society. This approach, however, treated war\u27s impact on cities as only temporary, hindered opportunities to reveal multiple political regimes\u27 spatial competition through war-oriented city planning and construction, which is crucial for city development, and their resultant urban form changes through time. In response, this study has examined city planning and construction activities during the short time gaps between multiple military conflicts, with various military objectives, and conducted by different political regimes in Shenyang, China. In accordance with archival research, a space syntax axis analysis has been used to quantify spatial dynamics throughout war-peace-war cycles to explore the impact of military-oriented planning on city-scaled development. We have found these planning strategies, initiated by specific military goals, acted as extensions of war planning, segregating the city and causing urban fragmentation. They also acted as a driving factor which promoted modernization of the city in the early 20th century. We conclude that wars oriented planning can alter a city\u27s development track and impact its structure and form through the creation of internally connected but isolated urban districts