After the massive cleanup and rehabilitation efforts on world-renowned Boracay last year, all eyes are on Manila Bay as the Department of Environment and Natural Resources began rehabilitation operations on January 26.
Environment Secretary Roy Cimatu started the campaign with the cleaning of the iconic bay’s coastlines and esteros, followed by a crackdown on establishments around the area that would be identified as sources of pollution and wastewater.
Not just trash collection
More than just a trash-collection initiative, the multiagency effort by the Philippine government to improve the environment of Manila Bay is meant to restore and maintain the bay’s water-quality level to make it suitable for swimming and other recreational activities.
On February 19, 2018, nearly a year before the rehabilitation project, Diwata-1 was able to capture an image of Manila Bay using its Spaceborne Multispectral Imager (SMI). Satellite data in the form of images yielded by the microsatellite can help track changes in water quality.
An analysis of turbidity, using the Formazin Nephelometric Unit (FNU) to measure water clarity, shows unmistakably turbid murky waters at the mouth of Pasig River appearing to flow out from the river.
Using a baseline of less than 5 FNU based from Figure 2, which generally indicates clear waters, more than 25 FNU units are shown to move out from the mouth of the river even extending inside the river.
Figure 2 shows that the extent of water pollution extends inland, which may point to the built-up areas inside the river as source of pollutants.
This means that residential and industrial runoffs, such as wastewater from factories, are dumped onto the river.
Long-term rehab
It is important to note that for the successful long-term rehabilitation of Manila Bay, the sources of pollution that enter the river, as well as other river systems that drain to the bay, should be identified and regulated, as well.
Figure 2 also helps in identifying that turbid waters are also present at the shores of Bulacan and Pampanga. These turbid waters have originated from aquaculture.
Impact on food supply
In the figure, the environmental impact of the growing demand for food to supply the growing Philippine population could be seen.
To keep up with supply, masses of aquaculture farms have to be set up for intensive fish farming, which is an activity commonly associated with using fish feed and fertilizers.
Unfortunately, unregulated usage of fish feed and fertilizers contaminate water, resulting in the milky blue waters at the area as shown in Figure 1. These also contaminate the waters of Manila Bay.
Diversifying and promoting alternative ways for aquaculture should be explored, as limiting aquaculture activities in this area—a possible effect of the Manila Bay Rehabilitation Project—may lead to a food-supply crisis.
Overall, Figure 2 showed the multitude of sources of the bay’s pollution.
Restoring the natural environment of the bay will require efforts to reduce waste material from sources. These sources can be easily identified by satellite images, such as those provided by the Diwata microsatellites.
Heavy metal pollution—bad for ecosystem, humans
What exactly are the effects of water pollution in Manila Bay?
For one, there is evidence of bioaccumulation of lead in fish muscles, as well as deterioration in muscle fibers of the fish captured from the bay.
Mamon, et al. (2016) found growth impairments to green mussel, a bioindicator of water quality, due to pollution in Manila Bay.
Heavy metal pollution is bad for both the ecosystem and humans, as these metals are transferable when eaten.
Manila Bay is one of the sources of food for many individuals who live in the area, and their health may be impaired from consumption of contaminated fish captured by fishermen.
High turbidity
Interestingly, applying the analysis to earlier images obtained through other satellites (Landsat) showed that high turbidity reaching above baseline levels occurred at the same general areas at same month.
Figures 3 and 4 show that turbidity is not a unique event captured by Diwata-1. It is most likely have been part of the bay for a long time.
The use of satellite images gives more dimension to the gravity of the rehabilitation project aimed to improve the coexistence of the environment and humans.
Sat images: Invaluable tools for rehab
Satellite images, such as those provided by Diwata-1, and their capability to provide timely and periodic information are invaluable tools to help the rehabilitation project.
In ideal conditions, satellite images can help track the temporal changes of turbidity within Manila Bay helping the efforts of the government to rehabilitate the bay.
With Diwata-2’s revisit capability, it could better monitor certain high-priority areas—such as Manila Bay—to compare water-quality changes over time.
Also, remote sensing is a cost-effective way to conduct large-scale assessments of water quality at the bay, as both Diwata-1 and Diwata-2 can capture a large area of the bay to be used for water-quality assessments.
Diwata-1 is a Philippine microsatellite deployed into orbit from the International Space Station (ISS) on April 27, 2016.
It is the first 50-kilograms satellite of the Philippine Scientific Earth Observation Microsatellite (PHL-Microsat) Program, a three-year research and development program funded by the Department of Science and Technology (DOST) of the Philippines.
The program is a collaboration between the University of the Philippines, the DOST-Advanced Science and Technology Institute (DOST-Asti) and Japan’s Tohoku University and Hokkaido University.
Diwata-1 has since captured over 36,000 images around the world and over 21,000 images of the Philippines data as of February 6.
PHL-Microsat and Stamina4Space Programs
The PHL-Microsat program is the country’s first initiative in developing the country’s capacity in space science and technology.
In its four years of implementation, it had successfully launched two microsatellites: Diwata-1 and Diwata-2; and a nanosatellite, Maya-1.
It is funded by the DOST, monitored by DOST-Philippine Council for Industry and Emerging Technology Research and Development and done through the collaboration between the University of the Philippines Diliman, the DOST-Asti, Hokkaido University and Tohoku University.
The PHL-Microsat Program is succeeded by the Space Technology and Applications Mastery, Innovation and Advancement (Stamina4Space) Program.
Stamina4Space is aimed at further developing deep expertise that enable and sustain the growth of a local scientific-industrial base in space technology and applications in the Philippines.
Through science-based policies and programs supported by innovations in space technology, Stamina4Space intends to contribute to building a resilient Filipino society and a productive, knowledge-based economy.