The three facilities are expected to provide a combined storage capacity of about 27,600 cubic meters.
The proposed facility at Remedios Circle will have an estimated capacity of 10,000 cubic meters and serve a catchment area of about 94 hectares.
The facility at Rajah Sulayman Park is expected to hold about 8,000 cubic meters, while the proposed facility at the Vito Cruz ASEAN Garden area inside the Cultural Center of the Philippines complex will have an estimated capacity of 9,600 cubic meters and serve a catchment area of about 60 hectares.
The facilities are designed to temporarily hold stormwater during heavy rains, reducing the volume entering already constrained drainage systems.
Artes said the Vito Cruz project would also include pumping equipment because water currently drains through gravity, making the area vulnerable to flooding when water levels in Manila Bay are high.
The existing 3.5-meter by 3.5-meter drainage line in the area is also heavily silted, with only about 30 percent to 50 percent of its capacity remaining, he said.
The MMDA plans to clean the drainage and provide the impounding facility as temporary storage before water is pumped out when necessary.
“If hindi naman po malakas ang ulan at hindi kailangan bombahin ng ating mga pumps, bubuksan lang po yung gate ... para natural po na makalabas yung tubig,” Artes said.
The three projects are part of a larger Metro Manila “sponge city” approach, which seeks to absorb, temporarily store and gradually release rainwater instead of immediately directing the entire volume into drainage networks.
Artes said the MMDA has identified 39 potential sites across Metro Manila for similar projects, with the remaining sites expected to begin construction next year using financing from the Asian Infrastructure Investment Bank.
The MMDA and Department of Public Works and Highways also have separate rain-catchment projects, including a planned facility at Luneta Park.
Artes said the agencies would have to coordinate to prevent duplication. “We just have to make sure na hindi nagkakapatong yan para walang aksaya,” he said.###