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Urban Spatial Growth Analysis of Khulna City

Md. Rejaur Rahman
Coordinator & Urban Planner
Asian Disaster Preparedness Center (ADPC)
House 531/4, Lane 11, Baridhara DOHS
Dhaka – 1206, Bangladesh
Cell: +8801717 087 089
E-mail: [email protected]

Abstract
Before 60s or 70s, the process of spatial growth of Khulna city was not so complicated because the industries solely, have shaped the spatial development. Now Khulna city has passed its glorious era but till now urban growth and land use change is taking place in a dynamic ways. This study dealt with the major dynamics of urban spatial growth i.e. land elevation, road accessibility, land price, location of important structures etc which were identified as the prevailing factors for urban growth in the City, to have an idea about the future spatial growth of the city. The study tried to find the answer of the question – what will be the shape of this city after 20 or 30 year from right now? This study tried to introduce a model, built by using ArcGIS Model Builder tool which is applicable for the Khulna city in any time if only the spatial factors are used. This model can be a useful tool for decision making for the concerned authorities about the expansion strategy and development control in a sustainable way.

Introduction
Urbanization and urban spatial growth are the result of combination of natural increase of the urban population and net immigration to urban areas (Firoz, 2004: 27-32). Urbanization can be regarded from demographic point of view, in terms of the proportion of country’s population living in towns and cities. It is observed that urbanization is very closely linked with industrialization, commercialization or the overall economic growth and development; and the process of urbanization exhibits a pattern in which the rate rises steeply as the early stages of industrialization are reached, and tapers off gradually when the proportion urban beings to reach a saturation point. Finally as most of the populations become urbanized, urbanization falls to keep peace with economic development, which is a continuous process.

The urbanization processes in Khulna started in 1836 (Murtaza, 2007). After that the process is going on. After the liberation war of Bangladesh the urbanization rate was reached its higher level high (KDA, 2000: 13) but in 2001 the urban population growth rate was 1.25 (Jahan and Rouf, 2007) which was very low than last four decades. The main cause is the economic decline of the city.

It was not known whether all these different patterns together may lead to an overall pattern – spatial, functional and demographic. The horizontal dimensions of space are certainly a basic determinant of population distribution (Batty et al, 2003: 36). Everyone wants to live pretty close to the city centre. But practically the people are did not do that. The living place are depends on their social, economic and many others factors. So, the people are trying to least distance in where there cost effective and suitable area base on working place distance, house rent, land price, transport accessibility, utility services etc (Masum, 2001: 40-42)

MATERIALS AND METHODS
The study tried to identify the influential factors of urban growth. There are mainly two types of urban growth influencing factors. Those are spatial and non-spatial factors.

Table 1: Category of urban growth factors

Spatial Factors Non-spatial Factors
  • Land Price Surface
  • Road Accessibility
  • Land Elevation
  • Private Housing Scheme
  • Demographic factors
  • Social factors
  • Economic factors
  • Political factors

Source: (Hiraskar, 1989: 27-35; Akter, 1996: 19; Sadia, 2000: 35-38)

To identify urban growth influencing factors the study has conducted a pilot survey. Total respondent of pilot survey was 48. The higher percentage represents the higher priority of the influencing factors. Both non-spatial and spatial factors are picked up (table 2).

For GIS analysis, spatial factors have been separated. Others influencing factors such as Migration, Social security, Community services facilities, Economic activities were excluded as the study dealt with only the spatial factors. The short listed spatial factors are:

Influencing Factors Level of influence according to respondent (%)
Land Price 17
Migration 24
Road accessibility 20
Height of Land 18
Social security 2
Private Housing 10
Community services facilities 1
Economic activities 8

Source: Field Survey, 2007

For GIS analysis, spatial factors have been separated. Others influencing factors such as Migration, Social security, Community services facilities, Economic activities were excluded as the study dealt with only the spatial factors. The short listed spatial factors are:

. Land Price . Road accessibility
. Land Elevation . Private Housing

RESULT AND DISCUSSION
Weightage of spatial factors by Analytical Hierarchical Process

For spatial analysis by GIS Model Builder needed the weightage of spatial influencing factors. The Weightage are calculated by Analytic Hierarchy Process (AHP). Weightage has been done by using AHP which considered not only the popular responses but also the relationship and affection between themselves (Alessio, 2004: 9-16; Vishv, 2003: 5).

First, we need to build a raw matrix from the table 3 and survey updates, where only variables considering the second option are selected. From the frequencies averaged value the considerations below are calculated.

If, Variable frequency average > = 0.5, particular raw position matrix value will be 2
Variable frequency average < 0.5, particular raw position matrix value will be 0 Coding the influencing factors

For analysis using AHP needed priority base multiple answers. In this study, 4 is high priority, 3 is medium priority, 2 is normal priority and 1 is low priority. Those priority base data were inputted in MS Excel sheet. Then compare each data with the other to make the raw matrix.

Table 3: Sample Priority base raw data

 

Table 4: Raw Matrix

The table 4 shows the average value of the 142 samples. If we name the column as i and the row as j and r is the cell value of matrix rij then there will be an equation to be followed to get the judgment matrix.

rij = [(Ki – Kj) / (Kmax – Kmin)] × (bm – 1) + 1 ————————–(i) when, Ki>=Kj

rij = 1 / {[(Ki- Kj) / (Kmax – Kmin)] × (bm – 1) + 1} ————————(ii) when Ki