| || || Chand, Subhash|
| || || Analysis of coastline change along the North East Coast of Viti Levu using multi-temporal and multi-scale remote sensed imagery and GIS|
Institution: University of the South Pacific.
Subject: Coast changes -- Fiji -- Viti Levu -- Remote sensing, Coast changes -- Geographic information systems -- Fiji -- Viti Levu
Call No.: Pac GB 451 .2 .C43 2016
Copyright:Under 10% of this thesis may be copied without the authors written permission
Abstract: This research conducted on a 25km coastline focuses on semi and fully automatic change detection techniques. The study categorizes the movement of coastline along the North ast coast of Viti Levu in Fiji. Coastline categorized as eroding and prograding by using two different techniques and data as aerial photographs and satellite imagery. The first technique deployed was a change detection algorithm using multi-temporal and multi-scale, geometrically corrected remotely sensed imagery. Changes observed for coastline change were for 23 years (1991-2014). The results of this change revealed areas of erosion and accretion for the entire study area. The second technique is a simple mathematical model, End Point Rate (EPR) and Net Shoreline Movement (NSM), used to calculate the rate of change for this coastline for the period of 31 years (1983-2014). Achieved by using geometrically corrected and orthorectified high-resolution aerial photographs, and satellite imagery. Although two different techniques used for this research, the results are consistent. The high-tech orthorectified images used in this research assisted in reducing errors and made features easily identifiable for extraction of vector coastlines. To confirm the changes from desktop application, a ground truthing exercise of this coastline was conducted, to compare the actual occurrence on the ground. The changes on the ground concurred 95% to the changes from the desktop application. Comparing multi-scale and multi-temporal classified remotely sensed imagery showed areas built with jetties that were visible on the change map as prograding coastline. The average rate of erosion in the area is -0.35m/yr. and is prograding at an average rate of +0.41m/yr. Areas lined with large strips of mangrove, the rate of accretion is higher than the rate of erosion. These figures could be maintained if developments are conducted sustainably, removing and clearing only desirable portions for developments and committing the developers to maintain the health of the coastal environment. vi Changes in this area were trivial, according to statistical results, but if long-term changes are considered, situation may worsen if the intensity of hurricanes increase. Most of the changes in this area were due to developments and settlement of people. Fortification of eroding coastline using hard engineering solution (gabion baskets and sea wall) is not viable. Whereas a more empirical and long term solution is by lining the coastline with vegetation (mangroves) which is self-maintaining and provide long term coastline protection. This was a trend noticed along the Volivoli resort, coastline mangroves trees were maintained and provide protection to the coastline from erosion and they beautify their landscape. Therefore, for long-term coastal durability relies on maintaining the vegetation along a coastline is very deductive. Finally, this research was successfully able to integrate the use of Geographical Information System and analyze remotely sensed data to locate areas of coastal erosion and accretion and quantify the rate of coastline change. Keywords: Geographical Information system, Multi-temporal, Multi-scale, Remote sensing, accretion, erosion, End Point Rate, Net Shoreline Movement