Assessing the feasibility of Landsat satellite data in monitoring water body and shoreline change along the coast of Keta

This research explores the use of freely available multispectral Earth Observation (EO) data to monitor changes in shorelines and banks along the Keta coastline and lagoon. The researchers acquired multispectral Landsat images from the years 1986, 1991, 2013, 2015, and 2018 to delineate their respective shorelines and lagoon banks using two water extraction based indices: Normalised Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI). When overlaid, the delineated water body and shoreline agree with their respective satellite images on Google earth. After the shoreline delineation, researchers used the open-source DSAS shoreline change analysis tool compatible with ArcGIS 10.1 to assess the coastline change rate along the Keta shoreline. A significant change in the shoreline was observed during the different years over the study period. The two shoreline change analyses, End Point Rate (EPR) and Linear Regression Rate (LRR) produced similar results with varying degrees of change. The delineated shoreline positions show a 1.64 m/yr. and 2.22 m/yr. mean erosion rate for EPR and LRR, respectively, between 1991–2018. The shoreline change rate agrees with recent literature, proving that EO data in water bodies and shoreline monitoring is a viable alternative to in situ data.