Rainwater storage urged as rainfall turns erratic

STORING RAINWATER will be more necessary as rainfall becomes more variable with climate change, highlighting the importance of sustainable water management, author of the 2024 Philippine Climate Change Assessment (PhilCCA) said.

Speaking at an online forum hosted by Climate Tracker Asia on Thursday, geologist and Environment Undersecretary Carlos Primo C. David said some of the most significant climate impacts will manifest in the water supply as rainfall patterns shift.

Mr. David said that while abundant rainfall will continue, averaging about 2,400 millimeters annually, climate change is affecting how rain is distributed throughout the year.

“What our scientists are seeing is that the pattern of rain is changing, meaning that we are moving towards a scenario where the dry season becomes drier and the wet season becomes even wetter. We are seeing longer dry days during the dry season,” he said.

Mr. David said these changes increase the risks of both drought and flooding, affecting agriculture, water supply, and other critical sectors.

In the 2024 PhilCCA, published by the Oscar M. Lopez Center for Climate Change Adaptation and Disaster Risk Management Foundation, Inc. last year, researchers found that the hydrological regions of Northwest and Central Luzon face very high frequencies of flooding.

Northwest and Central Luzon, Bicol, and Samar were also identified as having high to very high flood intensity, while Cagayan, Bicol, and Samar face a high risk of intense drought.

Mr. David said these risks highlight the need to shift toward sustainable water management, particularly by capturing and storing excess rainfall instead of allowing it to flow quickly into rivers and out to sea.

“The solution to both (flooding and drought) is a single strategy — to impound water instead of trying to push that water out into the ocean as fast as possible,” he said.

Mr. David said traditional flood control approaches, such as building dikes to confine rivers, often fail during extreme weather events and can simply transfer flooding to downstream communities.

Instead, he said the Philippines should invest in infrastructure that allows water to be stored during the wet season and used during dry periods. These include small dams, reservoirs, retention basins, and man-made lakes that can hold excess water upstream during heavy rains.

Mr. David said the country should also adopt nature-based solutions, including protecting watersheds, preserving natural waterways, and ensuring land-use planning gives rivers enough space to expand during heavy rainfall.

He added that efforts to improve water storage should be accompanied by measures to expand access to water services.

“There are still areas where there is no piped water in our communities. From our estimate, around 40 million Filipinos still lack access to safe, potable piped water in their homes,” Mr. David said.

To address these gaps, Mr. David said government programs are installing filtration systems in remote island barangays, building low-cost water refilling stations, and mapping water resources nationwide to guide long-term planning.

“Climate change simply intensifies (already existing problems in the water sector),” he said. “But it is also an opportunity for us to change our strategy, not only to address climate change, but to fix (long-standing) issues,” he added. — Vonn Andrei E. Villamiel