Metro Manila drainage system ‘very old’, no longer ‘adequate’ in preventing floods: DPWH

Waist-deep floods inundated a stretch of N.S. Amoranto Street in Quezon City on July 21, 2025. Mark Demayo, ABS-CBN News/File

MANILA — Metro Manila’s “very old” drainage network is no longer “adequate” enough to control floods unleashed by heavy rains, the Department of Public Works and Highways (DPWH) said Tuesday. 

DPWH Secretary Manuel Bonoan noted that pumping stations were working when the habagat dumped heavy rains in the capital region in recent days. 

However, he said that flood waters could not flow to the pumping stations because of the silted drainage system. 

LIST: Flooded roads in Metro Manila on July 22, Tuesday

“Gumagana po yung pumping stations. Ang problema lang po, hindi makadaloy yung tubig-baha papunta sa pumping stations because nga po yung mga drainage system, hindi adequate na para mag-convey ng floodwaters papunta sa pumping station,” he told DZMM. 

“Yung drainage system in Metro Manila is actually very old. Yung huling assessment ng drainage system in Metro Manila is actually 70 percent of it is actually silted na po,” the official added. 

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Bonoan noted that a new drainage system master plan was being developed with the World Bank's help. 

In the meantime, he said authorities were rehabilitating pumping stations, addressing the garbage problem that clogs floodwater inlets, and undertaking the Pasig-Marikina floodway program that aims to impede floodwaters from the Sierra Madre mountains from going to Metro Manila.  

MRT-7

The DPWH will also look into the Metropolitan Manila Development Authority’s (MMDA) report that the MRT-7 Batasan Station along Commonwealth Avenue contributed to flooding incidents in the area.

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“Kailangan tingnan po natin kung ano ba talaga ang dahilan ng sinasabi ng MMDA na nakabara yung MRT-7 na pinapagawa ng Department of Transportation,” Bonoan said. 

“We will offer technical recommendations kung papaano namin mapagtulong-tulungan ‘yan. But it has to be done immediately dahil ngayon pa lang nagsisimula ang tag-ulan, marami nang problema,” he continued. 

Transportation Secretary Vince Dizon earlier said he doubted the MRT-7 construction was affecting drainage systems. He said the construction is in the innermost lane, while the drainage system is on the outermost lanes.

Bonoan said he would discuss with the Quezon City government the potential causes of the floods in previously unaffected areas.

“We will discuss with them kung ano yung problema nila sa Quezon City. Ngayon lang nagkakaroon yata ng problema sa Quezon City, this year, kasi dati-rati wala naman masyado,” the DPWH chief said.

“Meron din kasing tributaries dito sa Quezon City na probably hindi makalabas yung tubig-baha sa Commonwealth na pumunta doon sa mga tributaries. Kakaunti lang po kasi yung tributaries dito sa Quezon City. At the same time, palagay ko hindi po integrated doon sa drainage system,” he said. 

STILL FLOODED 

Several areas in Quezon City remained flooded on Tuesday morning, including District 1 and 4, Sto. Domingo, Roxas, and Tatalon, said the city’s disaster office spokesperson Peachy de Leon. 

Some 6,012 families or 20,014 individuals in 55 barangays were staying in 111 evacuation centers in the city, she said. 

De Leon said garbage clogging the drainage systems was a factor contributing to the floods. 

“Ang drainage system ng Q.C., very extensive yan, prone talaga siya sa pagbabara lalo na ‘yung mga pasaway sa pagtatapon ng basura. ‘Yun ‘yung nakaka-cause ng pagdelay ng flow ng water waste lalo na yung tubig ulan,” she said.

She noted that Quezon City was within the catchment area of four river systems, namely the San Mateo River, San Juan River, Tullahan River and Meycauyan River, all of which are now flooded.

“Ang QC ay iniikutan ng 4 na ilog…Itong apat na ilog na ito ay nasa third alarm na,” she said.

She added that La Mesa Dam was overflowing, causing flooding in nearby barangays. As of 8 a.m. Tuesday, La Mesa Dam's water level was at 80.17 meters, above the dam's regular water level of 79.69 m.