Uploaded byMasuda Sultana
Erosion Analysis
This document summarizes a student's dissertation on analyzing Meghna River bank erosion in Haimchar Upazila, Chandpur, Bangladesh using GIS and remote sensing techniques. The student discusses the background of river bank erosion in Bangladesh, states the problem and objectives of the study, which is to identify and assess Meghna River bank erosion and recommend mitigation measures. The methodology describes using satellite imagery from 1988 to 2021 to analyze erosion and accretion. Key findings show the highest erosion from 1988 to 2000, and highest accretion from 2000 to 2010, with the most stable river area from 2010 to 2021. Mitigation measures discussed include structural options like planting trees and constructing embankments, and non-structural like dredging and
Erosion Analysis
- 1. Meghna River BankErosion Analysis At Haimchar Upazila, Chandpur using GIS and RS Techniques Presented by: Masuda Sultana B-150602060 12th Batch GEO-4207: Dissertation. Supervised by: Dr. Muhammad Al-amin Hoque Associate Professor Dept. of Geography & Environment, Jagannath University. Department of Geography & Environment JAGANNATH UNIVERSITY
- 2. BACKGROUND River bankerosion is the wearing away of the banks of a stream or river. More than 750 million South Asian people depend on the transboundary Ganges- Brahmaputra-Meghna river basin for their livelihood. Along with Bangladesh one million Souh Asian people affected and up to 200,000 displaced every year. River bank erosion is one of the frequent but the most unpredictable disasters that occur every year in Bangladesh (Hasan, 2016). The Lower Meghna moves down to the Bay of Bengal through the Haimchar Upazila at Chandpur and causes many impact like migration every year their livelihood. Geospatial analysis can help to identify the impact and to determine the solution for this severe problem. Khan et al. 2014; Akter et al. 2017; Hassan et al. 2017 conducted their research on Jamuna river band erision and Biswajit et al. 2013 conducted research on Meghna River bank erosion. Taleb et al. 2009 conducted research on socio-economic impact on displaced people at Haimchar Upazila, Chandpur District, Bangladesh. I will focus on the erosional change on the study area.
- 3. STATEMENT OF THEPROBLEM Bangladesh is a riverine country. People are directly or indirectly dependent on the rivers of this country. River plays a vital role in the livelihood pattern of the people who are mostly influenced by the rivers. River bank erosion is taking place in about 94 out of 489 upazilas of the country. Researchers have identified 56 upazilas with incidence of erosion. It is estimated that about 5% of the total floodplain of Bangladesh is directly affected by river bank erosion. The changing trend of Riverbank is creating many socio-economic problems in the proximate areas. Millions of people have been dislocated from their original living places because of acute riverbank erosion in Bangladesh. Every year, millions of people are affected by erosion that destroys standing crops, farmland and homestead land during heavy rainfall in the monsoon period which causes monsoon or riverine flood.
- 4. LITERATURE REVIEW Fromthe above review of literature, I can say many of the research had been conducted on the Jamuna River bank and those work had been done in the Meghna they were not in recent time. The above research work had been conducted before 2017. And the reseach had been conducted for socio- economic purpose to identify thw impact of the peopled near erosion prone area for continuous migration and displacement. Recently I did not found any research work on Meghna River bank erosion near at Haimchar Upazila, Chandpur district. So, I wanted to show Meghna River bank erosion-accretion and the change of river bank from 1988 to recent year 2021. I will also show some mitigation ways for preventing river bank erosion in the study area.
- 5. AIM & OBJECTIVES The aim of this research is to identify and assess Meghna riverbank erosion at Haimchar upazila, Chandpur. The following objectives are kept in mind in order to fulfill the aims: i. To discuss the factors causes river bank erosion. ii. To create Meghna river bank erosion map and assess erosion and accretion at Haimchar upazila. iii. To recommend the mitigation measures to prevent the bank shifting or erosion to prevent the displacement of the local people.
- 6. STUDY AREA Haimcharis an Upazila of Chandpur District in the Division of Chittagong, Bangladesh. The study area is located at between 23.0667° N latitude and 90.6375° E longitude. It is bounded by Chandpur Sadar and Bhedarganj upazila on the north, Hizla upazila on the south, Raipur and Faridganj upazilas on the east, and Gosairhat upazila on the west.
- 7. METHODOLOGY Data collection-Landsat and Sentinel imageries were downloaded from the United States of Geological Survey (USGS) website in order to analyze riverbank erosion with WGS 1984 UTM zone 46N. And Upazila shapefile were downloaded from the DIVA-GIS website. Software- ArcGIS 10.5 software and Microsoft Excel software used to complete the research work. Data methods- The satellite images of 1988, 2000, 2010 and the sentinel 2A image of 2021 were considered for image processing, image classification and image analysis for the study. The images will be processing through NDWI and unsupervised classification to find out the dynamic changes and erosion- accretion of the last 33 years’ period. Figure: Methodological framework. Satellite images Layer stake NDWI Unsupervised classification Erosion & Accretion assessment Map export
- 8. Time table Atimeline is a very important part of a project proposal. It basically shows the chronological order of events that we plan to do in our project. It is supposed to give the reader a broad overview of the project at a glance. It does not have to be very detailed. We need to schedule our time to do a dissertation in a time table. The target time table is given below: The target time of this research project is selected within 60 to 75 days. Activity Number of Days Topic or title selection 3 Proposal writing 12 Analysis 10 Report writing 15 Correction 10
- 9. FINDINGS From theanalysis of the satellite images, I have found that there was huge changed in the river bank and their erosion and accretion. The erosion rate was very high in the year between 1988 to 2000 and very low in the year between 2010 to 2021. The accretion was very high between 2000 to 2010 and low between 2010 to 2021. So, the highest rate of the unchanged river area was between 2010 to 2021. Table: Erosion and accretion data from 1988 to 2021 from the satellite images. Year Erosion (km2) Accretion (km2) Unchanged River (km2) 1988-2000 42.19 40.85 50.62 2000-2010 39.83 42.15 50.66 2010-2021 22.18 30.03 60.45 1988-2021 33.44 42.28 49.19
- 10. FINDINGS ▶ Here arethe images of erosion-accretion of 1988-2000 and 2000-2010.
- 11. FINDINGS ▶ Here arethe images of erosion-accretion of 2010-2021 and 1988-2021.
- 12. Mitigation For minimizingthe rate of the erosion in the study area, I will discuss some way of mitigation measures that will also lessen the impact on livelihood of the people of the affected area. There are two types of mitigation measures- Structural mitigation measures- Tree plantation near the bank area. Constructing embankment or dam. Riprap or hard armoring which can stabilize the riverbank. Non-structural mitigation measure- Dredging the channel for making the area shallow which will reduce the flow velocity. Re-channelized the bank area. Trap bag for improving barrier system.