Manila Bay rehab: Why the bay can’t be saved in 6 months

Aika Rey

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Manila Bay rehab: Why the bay can’t be saved in 6 months
If the Pasig River case is to be followed, it will take years – or even decades – to save Manila Bay


  • It took decades to achieve significant improvements In the water quality of the once biologically-dead Pasig River. It’s still far from being fully revived, and in the process, dumps wastes into Manila Bay.
  • The Pasig River Rehabilitation Commission (PRRC) monitors 14 stations along the river, all of which failed their parameters as of end of 2018.
  • The PRRC envisions a fully-rehabilitated Pasig River by 2032, or 13 years from now. 

Concluding Part
READ: Part 1: Manila Bay rehab: The challenge of cleaning up the nation’s waste

MANILA, Philippines – Thousands of volunteers stormed Manila Bay to sweep, pick up, and collect trash along its shore and waters in January, when the Philippine government kicked off its rehabilitation program.

The volunteers only have one thing in mind: to save Manila Bay. With their help, the Department of Environment and Natural Resources (DENR) promised that the bay will be cleaner in 6 months.

A “drastic change” will be felt. It may be “swimmable in 6 months or a year.” That’s what the DENR said.

But saving Manila Bay is a tough task. It cannot be done by the end of 2019.

It will take years or even decades, as the government will have to clean all the waterways that drain into it too. 

That means the government has to take up the challenge of finally cleaning the Pasig River, where more than a fifth, or 21%, of the bay’s wastes come from.

The Pasig River used to be the capital city’s lifeline. Resources like fish and other freshwater resources were drawn from it.

As recorded in history books, it used to be a key means of transport from Manila to Rizal.

But due to urbanization and increased population density in the capital region, the Pasig River was declared “biologically dead” in the 1990s. Sometimes the water is color black or green, and it emits smell very similar to rotten eggs.

In 1999, the Pasig River Rehabilitation Commission (PRRC) was created by then-president Joseph Estrada, with the primary mandate to clean the river’s waters and the esteros that drain into it.

Almost two decades later, the Pasig River is still dirty. But it bagged an international award that recognized it as the “most improved” river in Asia.

‘It’s all connected’

The Pasig River stretches 25 kilometers connecting Manila Bay to Laguna de Bay.

Its water is classified as “Class C,” ideally for fishing and recreational activities, propagation and growth of fish and other aquatic resources, for agriculture use, and for ferry services.

The Pasig River has 4 major tributaries, namely, Marikina River, Pateros-Taguig River, Napindan Channel, and San Juan River that all traverse the capital region. There are 43 minor tributaries that drain into it too.

Of the water bodies that meet the river, the San Juan River is infamously known to be the “most polluted” in 2018 that the PRRC had to put “trash traps” or nets to collect garbage from its waters.

According to a study published in the journal Nature Communications, 63,700 tons of plastic flow from the Pasig River into the ocean every year. That is equivalent to 10,600 elephants in terms of weight, the study said.

In April 2018, the PRRC collected 8,000 sacks of trash weighing around 4,000 kilos from the San Juan River alone.

According to the PRRC, there are “seasonal fluctuations” in water quality due to factors such as population density, weather condition, storm water runoff, and the amount of solid and liquid waste in it.

Despite being called a “river,” the Pasig River is actually a tidal estuary, meaning, the flow of water – and the waste that comes with it – depends on the tide.

During the wet season when the tide is high, water flows from Laguna de Bay to Pasig River, all the way to Manila Bay.

During the drier months, the flow is reversed and the dirty water that comes from Manila Bay to the Pasig River is brought to Laguna de Bay where there are fish pens.

PRRC environmental management division head Merliza Bonga told Rappler that a “more polluted” Pasig River is expected during the summer season.

“The river experiences a back flow or reverse flow phenomenon that causes floating garbage, wastes, and suspended solids from Manila Bay, being washed back to the river. Thus a more polluted Pasig River is observed during this period,” she said.

Bonga said that water along the river is usually black and stagnant due to increased evaporation during summer. That also means water is more concentrated, thus emitting a more pungent smell.

But Bonga said that water from Laguna de Bay is not exactly “clean.” Pollutants from fish pens in the area are being washed to the Pasig River, and eventually to Manila Bay.

On top of that, the PRRC also monitors plant growth during the onset of the rainy season. The water hyacinth on the river is not an indicator of good water quality as a normal person would think.

“Algal bloom is caused by freshwater bacteria that cause eutrophication, wherein the water becomes green because of excessive growth of plants and algae. This is attributed to high nutrients in the water that come from fertilizer run-off, untreated domestic sewage, and oxygen depletion of the water body, and eventually harm aquatic organisms,” Bonga said.


To evaluate water quality, the agency developed the Pasig River Unified Monitoring System that has 14 stations along the river. It records 6 indicators per quarter:

All these indicators are taken into account to grade a station. The data PRRC collects is being used to aid in decision-making and forming of techniques in programs and projects.

As of the 3rd quarter of 2018, PRRC data acquired by Rappler showed that all 14 stations failed.

That means the river has yet to achieve the acceptable quality for Class C waters.


A look into each of the indicators showed that nitrate concentration and oil and grease content in the water in all stations passed the desired level.

Oil and grease have been decreasing, with an average of 22% reduction in the past 4 years. However, it’s still slightly above the 2 mg/L standard at 2.71 mg/L in 2018.

Nitrate content is also at its lowest at 2.24 mg/L in 2018, well within the set standard.

From a whopping 1.2 trillion most probable number (mpn) per 100 milliliters of fecal coliform level in 2019, it is now down to 82.9 million mpn/100 mL in 2018.

Reduction in nitrate and fecal coliform level can be attributed to less direct domestic wastewater being discharged into the river, Bonga explained.

Water concessionaires achieved 21.91% sewerage coverage in Metro Manila in 2018. The Department of the Interior and Local Government was also able to relocate 49,642 informal settlers away from the capital region’s banks and shores.

Still, fecal coliform level is still too high compared to the 200 mpn/100 mL standard.

Other indicators also failed the standards despite the gains. In the last decade, biochemical oxygen demand (BOD) increased, especially in the last 4 years.

When BOD levels increase, dissolved oxygen in the water decreases because it is being consumed by decomposing pollutants, Bonga said. This is due to fecal coliform in the water, improper waste disposal, and fertilizer run-off.

Phosphate has been fluctuating in the past 10 years. It was at 2.20 milligrams per liter (mg/L) in 2009 and reached its peak in 2011 when it was at 16 mg/L.

It has gone down to 2.74 mg/L by the end of 2018, when PRRC started working with Laguna Lake Development Authority to regulate fish pens, to lessen feeds and fertilizer run-off into the river.

‘Long way to go’

In the past, the PRRC has championed in river restoration and claiming back riverbanks and stream’s easements that had been previously occupied by informal settler families (ISF).

It had also put up nets that catch trash to prevent it from traveling further into the bay.

In some parts of the Pasig River, the PRRC had succesfully installed slope protection on river banks. Some of the rehabilitated esteros have parks teeming with plants built by the PRRC already.

The PRRC has also adopted “bioremediation” on the “cleaner” esteros that can help break down organic waste and further improve its water quality. (READ: Is there hope for Pasig River rehab? Microorganisms can help)

The improvement in water quality contributed in the return of biodiversity in parts of the river system. There are over 100 species of trees and vegetation, at least 39 species of birds, 8 species of fish, and other aquatic plants, according to the PRRC.

On top of that, the PRRC said that working with their partners helped them progress in their goal. These include the LLDA regulating fish pens, and the National Housing Authority and local governments working on informal settlers, among others.

But the agency acknowledged that more has to be done to fully rehabilitate the Pasig River. 

PRRC executive director Jose Antonio Goitia said that they still face challenges on improper liquid and solid waste management, as well as encroachment on easements by informal settlers and some private structures.

“The Pasig River System becomes the hub of conflicting land use and transforms the river into a mega septic tank of the metropolis. The illegal dumping of solid waste into the river and waterways causes clogging of the drainage systems and eventually results in flooding,” Goitia said.

He also pointed out that the number of agencies involved in water and sanitation leads to “institutional fragmentation.” Limitation in resources and lack of regulatory powers under the PRRC is also a challenge.

“The annual budget given to the PRRC is not enough to cover the whole Pasig River and its 47 identified tributaries. Given the scope and magnitude of the problem in the Pasig River, the PRRC is doing its best to make both ends meet despite not having enough manpower and logistical provisions,” he said.

“The lack of full enforcement or regulatory powers also affect the PRRC, as it does not even have any power to arrest and penalize environmental violators, as well as arbitrate the conflicting interests of various stakeholders,” he added.

But he said that the vision of the PRRC is to fully revive the Pasig River in 2032, or 13 years from now, if all goes well.

“PRRC will integrate strategies for the restoration of the National Capital Region’s ecosystem, which includes not only riverbank improvements and nearby urban landscape developments but also the quality approaches to river management, and mechanisms for institutionalized involvement of the resource users and stakeholders,” Goitia said.

Tips for Manila Bay rehab?

To be clear, the PRRC is “not so confident” that Manila Bay will be swimmable by the end of 2019.

PRRC spokesperson George de la Rama told Rappler that Manila Bay has bigger problems than Boracay Island, thus, requires a different approach in terms of rehabilitation.

“This is very different from the case of Boracay. But we’re dealing with hectares’ worth of water. We’re talking about regions here. Pasig River rehabilitation is on its 20th year, and yet it’s still ongoing,” De La Rama said.

“We think that it will take time. If we’re only talking about fecal coliform levels, then maybe they’ll be able to achieve that. But there are still a lot of parameters to measure,” he added.

De la Rama said that one of the best practices of the PRRC is “going to the source.” (WATCH: Esteros and the river warriors)

What the government can adopt for Manila Bay rehabilitation is the PRRC’s river restoration and management framework, he said. This involves projects and activities in easement recovery, development of riverbanks, waste and water quality management, and public awareness.

He also pointed out that convergence among the national and local government, private sector, and other stakeholders is important to keep their eyes on the prize.

“They have to exert effort and put their best foot forward. Participating sectors must exert their best effort so that problems will be solved fast. They should also stick to their plans. There should be continuity,” De la Rama said.

Nonetheless, the PRRC fully supports the government’s programs. 

“We support the rehabilitation 100% because Manila Bay goes into the Pasig River, even Laguna Lake. We really have to support each other because whatever we both do contributes to our goal – and that is to make our waters clean,” he said.

For now, De la Rama said that all we have to do is wait. – with research by Addie Pobre/

All quotes in Filipino have been translated into English.


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Aika Rey

Aika Rey is a business reporter for Rappler. She covered the Senate of the Philippines before fully diving into numbers and companies. Got tips? Find her on Twitter at @reyaika or shoot her an email at