Bathymetry Mapping of Hikkaduwa Coral Reef Using Multispectral Satellite Imagery

Abstract

In previous era, bathymetry was determined by using conventional methods which retrieved the depth at a single point at one time. Later it was developed to many kinds developed systems which can determine water depth more accurately, but high in cost. In recent years, with remote sensing data it can be easily map at shallow water areas up to 25m. The idea behind this method is to use the reflection intensity of the various wavelengths captured by the satellite sensors. The ENVI Suite Relative Water Depth Tool empowers to create an item with relative water depths rapidly. As they do not appear actual depths (the relative depths are scaled from zero to one), the water depth comes about are relative, and the purpose is to deliver a large feel to the area's bathymetry. The yield must still be calibrated to field information to assess real depth. While coral reefs are found in Sri Lanka, the reefs around Hikkaduwa are among the most diverse and accessible which has a typical fringing coral reef with a shallow crest. The reef has suffered high degradation due to both natural and human activities. According to analysis, due to the relative significance changes of bathymetry comes about from the today, the coral reef has, by comparison, changed around 48.5% over the past 25 a long time (1995 to 2020) due to both natural and human exercises. By summarizing the real values for each bathymetry outline, it can be analyzed that between 2002 and 2019, the coral reef debased by roughly 5%, depending on the increasing of average depth within the study area. This has led to the creation of a new tool for the use of multispectral satellite image data to map shallow water bathymetry, referred to as satellite derivatives bathymetry. And there is no data available for evaluation to be used to assess the performance of the satellite-derived models. And with the lack of high resolution and undisturbed (i.e. without cloud disturbances) multispectral satellite imageries, it limits the derivation of bathymetry data.