‘Use Project NOAH flood maps, build cisterns’

MANILA, Philippines — As thunderstorms continue to intensify, geologist Mahar Lagmay urged the public and the authorities to maximize Project NOAH’s hazard maps to identify flood-prone areas and prevent severe flooding.

Project NOAH, or the Nationwide Operational Assessment of Hazards, helps citizens pinpoint areas susceptible to flooding using 30 years of rainfall data from the state weather bureau.

Lagmay, executive director of the University of the Philippines Resilience Institute and project leader, said the maps are especially useful for people seeking safe places to park vehicles, dine or plan school activities.

“When you look at this map, you’ll see many places spared from flooding,” Lagmay told The STAR’s online show “Truth on the Line” on Thursday. “The red and orange spots indicate low-lying areas where rainwater flows. So, this helps the people identify safe places during a thunderstorm.”

Lagmay noted that Project NOAH is also beneficial for schools preparing for the academic year, particularly with heavy rains and possible class suspensions.

According to a 2018 conference paper presented in Thailand, the project aims to enhance emergency response and disaster mitigation through mapping technology and other scientific tools.

It has been under UP’s supervision since June 2017, after the Duterte administration ordered its shutdown earlier that year due to funding issues.

Lagmay revealed that today’s weather systems often bring floods with a return period of 100 years, overwhelming drainage systems designed only for 50-year floods.

To address this, he urged the Department of Public Works and Highways (DPWH) not to rely solely on expensive concrete structures such as dikes and levees.

“Let’s not pour billions of pesos into concrete; that should be the last resort,” Lagmay said, stressing the importance of nature-based solutions.

Among these are detention basins built beneath parks and courts to collect rainwater and ease street flooding.

One of the earliest cisterns, under Burgos Park in Bonifacio Global City, can hold up to 22 million liters of rainwater – roughly the volume of eight Olympic-size swimming pools.

Quezon City is constructing 150 similar basins, while Valenzuela plans to build one under a portion of MacArthur Highway near the North-South Commuter Railway.

Weather update

Meanwhile, the state weather bureau reported that a low-pressure area (LPA) spotted west of Northern Luzon has a medium chance of developing into a tropical depression or storm this weekend.

As of 3 p.m. yesterday, the LPA was located 175 kilometers west of Sinait, Ilocos Sur, according to Philippine Atmospheric, Geophysical and Astronomical Services Administration. It is moving slowly northwestward toward southern China and may exit the Philippine area of responsibility by tomorrow.

The LPA, along with the southwest monsoon, is bringing heavy rains over Ilocos Sur, La Union, Benguet, Pangasinan and Zambales, where up to 100 millimeters of rain could fall within 24 hours.

PAGASA warned of possible flooding, flash floods and landslides, particularly in low-lying and mountainous areas.

Rains are also expected in Metro Manila, Calabarzon, Mimaropa and parts of the Visayas and Mindanao, with thunderstorms likely in the afternoon and evening. While no gale warning was raised, sea conditions in the West Philippine Sea and extreme Northern Luzon may become rough, with waves reaching up to 2.5 meters. — Jose Rodel Clapano, Christine Boton

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