Assessing the Eutrophication Potential of Manila Bay using Landsat 8-derived NDVI and NDWI Parameters

Proponent/s Name/s (Last Name, First Name, Middle Initial)

Sean Andre D. Calajate, De La Salle University, ManilaFollow
Tristan Josef A. Tolentino, De La Salle University, ManilaFollow
Francis Edric M. Robles, De La Salle University ManilaFollow
Maria Francesca I. Rojas, De La Salle University, ManilaFollow
Angela Nicole S. Masongsong, De La Salle UniversityFollow
John Ray Cordova Estrellado, De La Salle UniversityFollow

Document Type

Poster Presentation

Research Advisor (Last Name, First Name, Middle Initial)

Masongsong, Angela Nicole S. and Estrellado, John Ray C.

Abstract/Executive Summary

Eutrophication, characterized by the presence of excess aquatic nutrients, poses a detrimental environmental threat to Philippine water bodies such as Manila Bay, consequently degrading water quality and augmenting algal blooms that harm aquatic life. This may be caused by a variety of issues, such as urbanization and assorted nutrient overloading. Thus, monitoring of its susceptibility to eutrophication is a valuable step in mitigating its potential effects. This study utilized Landsat-8 derived satellite imagery of Manila Bay to analyze the eutrophication potential (EP) of the bay from January 2024 to December 2024 using the open-access QGIS software for processing. Two spectral indices, namely the Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI), which are commonly used for monitoring vegetation and water quality, respectively, were used to map and analyze the EP of Manila Bay and three selected focus areas (commercial, vegetation, and Pasig River outlet) across 12 months and during the wet and dry seasons. Data collection and processing resulted in the creation of maps that visualize EP per month, per Philippine season, and per chosen focus area. The dry and wet seasons obtained EP values of 0.571429 and 0.578947, respectively, indicating moderate EP for both seasons. Additionally, multiple graphs were also created to visualize and compare changes in EP with time and location. Fluctuations in climate and human activity cause shifts in EP, while minimal differences are seen when cross-comparing the EP of certain focus areas within Manila Bay. The study recommends the verification of results through various field validation techniques, either in conjunction with remote sensing or as an alternative technique itself. Additionally, other eutrophication parameters, indicators, and indices are also recommended for further analysis.

Keywords

eutrophication; Landsat 8; Manila Bay; NDVI; NDWI