Spatiotemporal Change of Urban Water Bodies in Bangladesh: A Case Study of Chittagong Metropolitan City Using Remote Sensing (RS) and GIS Analytic Techniques, 1989-2015

This is an empirical study that attempts to explore the spatiotemporal changes of Urban Water Bodies (UWBs) in the Chittagong Metropolitan City from 1989 to 2015, using Remote Sensing and Geographic Information Systems analytic techniques. More precisely, Ground Truthing, along with Landsat (TM) data and/(OLI) satellite images was collected for the years 1989, 2001, 2010 and 2015, respectively; Checklist Survey, Key Informant Interviews and observation (overt) methods were also used for conducting the study. Narrative Analysis along with statistical tools, especially SPSS (version-20), was applied as well. The study reveals that nearly 1249 types of water bodies were detected by the checklist survey and 'Ground Truthing Method', beside 1352 types of water bodies were identified through interpretation of series satellite images in the Metropolitan area. The total number of water bodies in Chittagong City was found declining gradually, because nearly 1605, 1526, 1400 and 1352 types of water bodies were detected in 1989, 2001, 2010 and 2015 years, respectively. Although the regression analysis curve prescribed the changing pattern or decreasing rate of UWBs was similar to 10% which represented per year interval. Besides, the emerged and filled nature of UWBs was confused conditions. Some water bodies were emerged or excavated at southern and western edges of the coast due to soil collection for road construction and commercial fishing purposes. Besides that, many water bodies filled at every place in city area due to unplanned urbanization and industrialization, new settlement and housing, land pricing and fragmentation, unlawful encroachment and violence of Real Estate Corporation and so on. Therefore, strengthening of laws and policies and proper coordination among urban autonomous agencies will be significant to stop illegally filled of water bodies and to protect water bodies in a Chittagong Metropolitan city in Bangladesh.