In late December 2020, an Iloilo fisherman gained online fame when a photo of him catching a humongous 20-kilogram (kg.) longfin trevally, locally known as lison, from the Iloilo River near the Freedom Grandstand circulated on the Internet. The same reaction was seen online in October 2021 with the viral video of an angler struggling to reel in a 16-kg. bulgan or Asian sea bass barramundi caught along the Esplanade.

It was only a decade ago when the Iloilo River was on the brink of being “biologically dead” — so polluted that fish could hardly survive. Thanks to the efforts of the city government and the private sector to revitalize the waterway, the river is again teeming with marine life and biodiversity. Fish, crustaceans, and even migratory birds thrive in its brackish waters.

The first phase of what would become the 10-kilometer (km.) Esplanade, now a tourist drawer, was opened to the public in August 2012. The banks and easements of the river that were once dotted with shanties and stilt houses were developed to become a walkable open community space traversing the districts of Lapaz, Lapuz, Mandurriao, Molo, and Iloilo City Proper. 

Visible pollution was curbed by installing solid waste catchments in the river’s major tributaries. The estuarine was cleared of sunken and derelict ships that often doubled as floating informal settlements. The Department of Environment and Natural Resources (DENR) also laid down and strictly enforced riverbank easement restrictions.

There’s still more work to do, however. Experts have been monitoring the water quality of the river, which had fluctuated based on indices recorded. 

Domestic wastewater ends up in Iloilo River due to the absence of a citywide sewerage system. Some barangays, especially in Iloilo City Proper, have septic systems, but they are said to be poorly maintained.

“Continuing monitoring of the water quality allows our office to identify trends in relation to the present plans and programs for the Iloilo River,” said lawyer Ramar Niel Pascua, regional director of the Environmental Management Bureau (EMB) in Western Visayas.

“It is evident with the results that substantial steps have already been made. However, water quality assessments also clearly present that the Iloilo River still requires further action to promote and sustain its compliance to our water quality standards,” Pascua said.

An examination of data shows that two tributary creeks in particular –– Dungon Creek and Calajunan Creek — are a cause for concern.


This last decade, the estuarine has increasingly become an integral element in most of the local government unit’s landmark projects, considering the body of water not only as a local icon but also a symbol of the city’s prospects in sustainable growth and development. PHOTO BY JOEBEL GALICTO



 BOD and fecal coliform levels 


Twelve strategic water quality monitoring sites were established along the waterway to trace and oversee the 10-km. estuarine year-round. 

  1. Muelle Loney Bridge
  2. Quirino-Lopez Bridge
  3. Forbes Bridge
  4. Benigno Aquino Avenue
  5. Carpenter's Bridge
  6. So-oc Bridge
  7. Mouth of Dungon Creek
  8. Dungon V Bridge
  9. Calajunan Creek, Downstream Dumpsite
  10. Calajunan Creek, Downstream of Industries 
  11. Calajunan Creek, Upstream
  12. Mambog Dam, Mambog Creek


These sites are tested regularly for chemical factors such as dissolved oxygen (DO), biological oxygen demand (BOD), total suspended solids (TSS), salinity, and heavy metal content. 

They are also tested for biological parameters such as counts of fecal coliform bacteria, species pathogens, and viral loads.

For a body of water to sustain aquatic life, the freshwater resource needs to contain at least 5 milligrams (mg.) of DO per liter of water (mg/l), based on standards of the DENR. Anything lower than 3 mg/l would cause undue stress on fish and marine species and gradually suffocate them to death. 



Based on the latest readings, all stations of the Iloilo River comply with or are very close to the minimum baseline to foster life. The 12 monitoring sites recorded DO levels of 4.8 mg/l to 6.9 mg/l.

As for the BOD, which represents the amount of oxygen consumed by bacteria while they decompose organic matter in the water, the lower the better. Iloilo recorded BOD levels ranging from 1.8 mg/l to 38 mg/l during the same timeframe –– a drastic reduction from 170 mg/l back in 2010. 

The annual average TSS concentration in all sampling stations also improved during the same timeframe and met the 80 mg/l baseline.



(From left) A local boatman scavenges for scraps at a congested embankment in Molo District; a man paddles away from a cluster of informal settlements along the Iloilo River in Molo District; a fisherman casts out fishing lines near the Iloilo Provincial Capitol in downtown Iloilo City. PHOTO BY JOEBEL GALICTO



One biological parameter raised red flags, however. Iloilo River was found to have fluctuating fecal coliform concentrations, based on water quality indices published on the Iloilo-Batiano River Systems Water Quality Management Area (WQMA) Report.

Fecal coliform, measured in terms of the most probable number per 100 milliliters (MPN/100 ml), indicates the presence of bacteria commonly found in the intestines of warm-blooded animals. It shows that Iloilo River remains inundated with untreated wastewater.

The river’s fecal coliform concentrations rose and fell three times in the past decade, based on the 2019 Iloilo Water Quality Report published by DENR Western Visayas.

Iloilo River recorded relatively low fecal coliform concentrations in 2021, likely due to the pandemic. The readings ranged from 3,181 to 653,146 MPN/100 ml, although still above the guideline values of 200 MPN/100 ml. 

The numbers of the previous year showed sharp increases, ranging from 10,042 MPN/100 ml to 2,400,000 MPN/100 ml based on data from the 12 monitoring stations. The figures, based on the latest Annual Water Quality Monitoring report, were higher compared with 2010 despite rehabilitation efforts.




Data from the EMB’s 2017 National Water Quality Status Report show that untreated domestic sewage is the country’s largest source of water pollution effluent at 33%, followed by commercial and industrial waste at 29%.

Out of the 421 principal rivers in the country, some 180 were classified as severely polluted that year, while some 50 mostly urban inlets were declared effectively biologically dead and unable to sustain life. 



Iloilo River fared far better than the other urban waterways in the country. In comparison, the Manila Baywalk Area in the country’s capital recorded coliform concentrations of nearly 100 million MPN/100ml while the Estero San Antonio de Abad, one of Pasig River’s major outfalls that empty into the Manila Bay, recorded 35 million MPN/100ml.

Experts were concerned that revitalization efforts had made very little headway when it comes to managing the sewage of Iloilo City. 

For some comparison, when Boracay was closed in 2018, the coliform level was at 47,460 MPN/100ml.

“Pollution generation of the river resulting from high fecal coliform concentrations were identified mostly from domestic, commercial, and industrial wastewater discharges, septic tanks, and backyard piggeries,” said Pascua of EMB Western Visayas, in a statement. 

Iloilo River receives untreated sewage from 120 of 180 barangays (villages) in Iloilo City and some 50 additional barangays outside city limits, according to Iloilo City Environment and Natural Resources Office (CENRO).

A good number of households along the Iloilo River do not have septic tanks, so all of their household and livelihood liquid wastes go directly to the water, Cenro officials said. There are few public toilets, let alone a well-maintained sewerage system.

It could have been worse. The Iloilo Batiano River Development Council, which led rehabilitation efforts, believes the relocation of some 7,000 informal settlers from the banks of the estuarine since 2010 reduced solid waste by at least 4,000 kg. daily and untreated wastewater by at least 120,000 liters. 

The council, which fostered a partnership between regulators and the private sector, also said it helped avoid the discharge of 1.4 million liters of untreated sewage into the Iloilo River daily.

But there are 35 villages along the banks of Iloilo River, while 75,123 residents live along the estuarine, according to the 2020 Census.

Some 10 barangays sit adjacent to the Dungon Creek alone, with a total population of 31,922 based on the 2020 Philippine census.


 Focus on 2 polluted creeks 


Disaggregated data from the 12 monitoring stations showed which particular areas posed concerns.

The main stretch of the Iloilo River – the entire stretch from Parola to Mulle Loney until the So-oc Bridge covered by the six monitoring stations – has shown largely steady improvement. The annual average DO of the Muelle Loney Bridge station has consistently complied with the 5.0 mg/l water quality guideline value (WQGV) for Class C bodies of water since 2013.

The average DO of Quirino Bridge, Forbes Bridge, and So-oc Bridge complied with the WQGV in 2020. Only Carpenters Bridge (4.8 5.0 mg/l) and Benigno Aquino Bridge (4.0 mg/l) were marginally below the threshold, but showed consistent improvement.

BOD and TSS parameters have also consistently complied with standards.

Iloilo River’s upstream tributaries are the sore spots of the rehabilitation efforts. They have been the sources of much of Iloilo River’s waste and domestic garbage, as they are populated by residents who do not have access to septic tanks. 

A study by the Iloilo City Health Office estimated that households produced 5,625,088 kg. of BOD annually from the use of septic tanks and 588,672 kg. of BOD a year from open pits and latrines. Out of this, some 327,040 kg. of BOD per year find their way into Iloilo’s waterways as untreated discharges.

“As such, proper septage management is highly recommended to address this exceedance of discharges. Households with poor or lacking septage facilities contribute much to the fecal coliform concentrations as the Iloilo River serves as the recipient of all household discharges in the city,” Pascua explained.

Two tributaries have been identified as most problematic — Calajunan Creek and Dungon Creek. 



Calajunan Creek absorbs domestic waste, leachate from the Iloilo City garbage disposal site and sanitary landfill, as well as agricultural run-off and industrial wastes from beverage factories, piggeries, fishponds, and coconut oil mills, according to a study by EMB Western Visayas.

Dungon Creek absorbs discharges from fishponds and domestic waste from nearby residential areas and establishments along the embankment, the same study found.

Solid wastes from households, ocean vessels, and the like also find their way to the river system. During high tide, the river is vulnerable to wastes carried by the ocean current.

Fecal coliform levels in the two creeks have been a cause for concern. Samples on the main stretch of the Iloilo River taken in 2020 exceeded the 200 MPN/100 ml threshold. Carpenters Bridge recorded 10,042 MPN/100 mL while Benigno Aquino Bridge recorded 83,840 MPN/100 ml. 

The river’s average soared to the millions along Dungon Bridge (2,495,048 MPN/100 ml), and all the Calajunan monitoring stations (2,208,387 MPN/100 ml downstream from the Calajunan dumpsite and 1,258,230 MPN/100 ml downstream of the nearby industries). 

What these two areas have in common are congested populations, murky creeks, and improper solid and water waste disposal.

“Dungeon Creek is among the underdeveloped areas of our river system. It is now being considered to be declared a ‘non-attainment area,’ in dire need of measures to counter its further degradation,” said Cenro chief Noel Hechanova, in an interview with the Philippine Center for Investigative Journalism (PCIJ). 

Hechanova said interceptors and catchments needed to be installed at the mouth of Dungon Creek.

“By my own estimation, some 80 percent of the contaminants that plague our river come from informal settlements and poorly maintained poso negros, or septic tanks,” he said. 


 Mangroves help 


At least two factors have helped improve water quality of the Iloilo River. 

One, it is an estuary river. “The Iloilo River is unique in that it’s not really a river, it’s a mouth, it’s an invagination of the sea,” said Dr. Ian Padilla, a physician and microbiologist based in the University of the Philippines (UP) Visayas. 

“So cyclically, with the tide every day, seawater comes in, dilutes and washes out all the pollutants in the main stretch and flushes it out to sea. In one way it’s good because there is a continuous replenishment of the river, but in another way it’s also bad because if you have a lot of pollutants then it simply gets transferred to the coastal seawater,” he explained.

Iloilo River is an “arm of the sea,” said Arjun Calvo, a lawyer and special planning officer for the rehabilitation of Iloilo and Batiano rivers at EMB Western Visayas.

“During high tide, the waters of the Iloilo River flow into the Dungon and Calajunan creeks and then back out again at low tide, potentially bringing with it a backwash of contaminants from these tributaries into the main stretch of the Iloilo River,” he said. 

Two, Iloilo City’s pockets of mangroves have contributed to improving the salient water quality along the Iloilo River since these trees feed on organic matter that would otherwise contaminate and overwhelm the waterway. 

“Mangroves are very good in terms of utilizing the organic matter in the river,” Padilla explained. “They can siphon and break down larger organic material from the water. So it’s great in terms of recycling nutrients. [Mangroves] provide  an ecosystem for other invertebrates and other plants to be able to grow, so they’re also very good indicators that the ecosystem is trying to recover.”

Iloilo City boasts one of, if not the densest urban mangrove ecosystems in the country. It’s home to 23 of the country’s 35 endemic mangrove species belonging to nine families.

Mangrove areas along the Iloilo River, Batiano River, and the coastal areas of Iloilo City covered 132.2 hectares, an area equivalent to 3,028 basketball courts or a tenth of the total land of Boracay Island, based on mapping spearheaded by Prof. Resurreccion Sadaba of UP Visayas.

Of the total, 44.57 hectares sit along the banks of the Iloilo and Batiano Rivers.

Aside from protecting shorelines from storms, flooding, and erosion, mangrove ecosystems can sequester a disproportionately high amount of carbon per unit area compared with other marine and freshwater wetland ecosystems.

A 2015 study supported by the US Agency for International Development concluded that the sequestration potential of mangroves in the Batiano and Iloilo Rivers totaled 194,682 metric tons of carbon dioxide equivalent (mtCO2e).

This total sequestration potential is equivalent to taking about 54,746 gasoline-powered cars off the road in a year, switching 8.6 million incandescent lamps to light-emitting diode bulbs, or growing more than 6.6 million tree seedlings for 10 years.

However, Iloilo-based marine scientist Jurgenne Primavera, chief scientific mangrove advisor of the Zoological Society of London, contends that robust water treatment solutions remain of utmost necessity to keep this valuable arm of the sea from further degradation.

“Mangroves can absorb fertilizer, nitrogen, phosphorus, and nutrients, including coliform from human settlements, from the water and use it for their growth,” she said.

“That is why in brackish areas where mangroves thrive, the water is relatively clean. However, expecting mangroves to shoulder the entirety of the cleanup is an unrealistic band-aid solution. A genuine remedy addresses the problem at the root,” she added. 

Because it’s a public health concern, she said, “proper waste disposal and a functioning sewage system are necessary to reduce the coliform levels of the river, otherwise untreated wastewater will continue to plague our river.” 


 Costly, laborious solution 


The solution is clear, but it’s going to be costly. Iloilo City needs a sewage system.

Majority of the city’s population relies on private septic tanks. These poso negros need to be siphoned every few years by private contractors. Wastewater may begin seeping into the soil if the tank is poorly constructed or poorly maintained.

“We do hope that there will come a time that all barangays in the city will be connected to a comprehensive sewerage system, but that will still take a lot of time and a lot of funding,” Hechanova said.

“There are also some 33 water-borne diseases that can be transmitted if you swim or make contact with contaminated waters, so it is not only an environmental concern, but also a public health one,” he added.

Calvo said a dedicated sewerage system would also require a large-scale revamp of the city’s existing infrastructure, since drainage canals for rainfall run-off would need to be separated from sewer lines. Septage tanks in homes and businesses will also have to be connected to the system.

“So imagine the laborious and painstaking process of planning and laying out this passive infrastructure on top of our existing pipes and waterlines, also finding an area for the construction of our own wastewater treatment plant. It is a mammoth challenge that entails millions, if not billions, in necessary funding,” he said.

Ultimately the overall health of the Iloilo River will remain in peril if the tributaries carry on as “non-attainment zones” since wastewater from these areas can easily enter and leach into the main stretch of the river, he said.

“That is why it is important that we also protect and conserve our creeks. All our adverse actions in these tributaries can build up and potentially cause adverse effects on the Iloilo River. If we continue to fail to clean up our own creeks, what we’ll be doing is a disservice and added burden to the Iloilo River,” Calvo concluded. END


Rhick Lars Vladimer Albay produced this report under PCIJ’s Uncovering LGUs fellowship program.

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