MANILA -- Two former Cabinet officials are advocating more investments in rainwater harvesting nationwide to increase supply of water for agriculture and other uses while addressing disasters like flooding.

The Philippines annually receives about 2,400 mm of rainfall -- one of the world's highest and which can be stored for such purposes, former agriculture secretary Dr. William Dar and ex-environment chief Dr. Elisea Gozun said.

"We need to immediately consider rainwater harvesting as a major strategy not only for agriculture but for household uses also," Dar said.

Gozun, meanwhile, said the government should encourage the public to store available water for future use, especially in agriculture.

The call was made after the water supply shortage in parts of Metro Manila and Rizal province due to El Niño or prolong dry spell.

Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) Administrator Dr. Vicente Malano said the Philippines has excessive rainfall but most of this goes to the seas.

"We use less than 10 percent of rainfall," he said in a recent press conference in Quezon City for PAGASA's annual National and World Meteorological Day celebration, urging all sectors to conserve water.

Data that Dar recently presented at the World Water Day summit in Quezon City indicated the exigency to tap rainwater harvesting as a means to increase water supply nationwide.

Agriculture alone already accounts for some 80 percent of water usage in the country, the data showed.

The projected 2025 water demand in agriculture may surge to a high 72,973 million cubic meters (MCM), the data showed.

The data also indicated that the 2011-2016 average expansion of national irrigation systems in the country was about only 1.4 percent.

Estimated high 2025 water demand for domestic and municipal users (8,573 MCM) as well as industrial uses (4,997 MCM) further elevated need for increasing water supply nationwide, the data showed.

Despite having an abundant rainfall, Dar said the country's rainwater harvest rate is only about 4.0 percent.

India's harvest rate is around 60 percent even if the annual rainfall there is about 700 mm, he noted.

He said rainwater harvesting was among measures that authorities had identified for helping mitigate the impacts of the strong 1997-1998 El Niño.

"Until now, however, there's low investment in rainwater harvesting," he said.

The Bureau of Soils and Water Management (BSWM) has been developing small-scale irrigation projects like small water-impounding facilities so agricultural areas can have supplemental water supply.

These projects also help control floods while catering to fishery and livestock production as well, the BSWM said.

Gozun, meanwhile, recommended the construction of more small water impounding facilities in the country to increase water supply and mitigate flooding in low-lying areas.

Rainfall need not always end up as floods since such facilities can store rain, she said.

She noted that mitigating flooding through massive rainwater harvesting will help reduce crop destruction and top soil erosion.

Building impounding facilities in uplands will maximize agricultural production, Gozun said.

"There's more than 20 million people living in uplands -- they'll have water if we do that," she said. (PNA)