IMUS CITY, Cavite — One of Cavite’s biggest flood-control facilities is officially moving into its next phase, with the Department of Public Works and Highways and the Japan International Cooperation Agency turning over the Imus Retarding Basin to local authorities—putting the long-term success of the massive project increasingly in the hands of local government.
The 35-hectare floodwater catchment facility in Barangay Anabu 1-G can store about 1.12 million cubic meters of water, roughly equivalent to 448 Olympic-sized swimming pools. Its purpose is straightforward but critical: when the Imus River swells during intense rainfall, excess water can spill into the basin instead of immediately inundating communities downstream. The stored water is then released gradually once river levels subside.
Public Works Secretary Vince Dizon said local officials had described flooding in parts of Imus before the retarding basins were built as reaching chest level. Dizon said the basin now provides floodwater from the main river with a dedicated holding area and claimed that the severe flooding once experienced in the city has become “virtually gone.” That assertion remains an official assessment and should be viewed alongside actual community experience during future extreme-rainfall events.
The September 1 turnover was attended by Dizon, Interior Secretary Jonvic Remulla, Cavite Governor Francisco Gabriel “Abeng” Remulla, Vice Governor Ram Revilla, Imus Mayor Alex Advincula and representatives of JICA. Reports from both the Philippine News Agency and Journal News described the ceremony as the formal turnover of the facility to Cavite authorities, with PNA saying operation and maintenance responsibilities are being transferred to the local government.
It is not simply a giant empty reservoir
A retarding basin works differently from a conventional dam. Instead of permanently storing a huge body of water, it temporarily receives storm runoff when river levels become dangerously high, reduces the peak flow moving downstream and later releases the water at a controlled rate.
That is particularly important in highly urbanized sections of Cavite, where roads, subdivisions, commercial developments and other paved surfaces can reduce the amount of rainwater that naturally infiltrates the ground. The Philippine Information Agency has identified land conversion and heavy rainfall as significant parts of the province’s flooding challenge.
The Imus facility is paired with another retarding basin serving the Bacoor River system. JICA said when the facilities were inaugurated in 2021 that the Imus basin covered about 35 hectares while the Bacoor facility provided another nine hectares of temporary floodwater storage.
The engineering design came from a comprehensive JICA-backed flood-management plan. DPWH said approximately 2 million cubic meters of soil had to be excavated to create the Imus basin, which reaches roughly seven meters deep in parts and incorporates surrounding dikes, an overflow structure and drainage controls.
Why the 2026 turnover matters if the basin was already inaugurated years ago
One important detail can easily be lost in current headlines: the Imus Retarding Basin itself is not an entirely new facility unveiled for the first time in 2026.
JICA and Philippine government reports show that the Imus basin was already inaugurated in September 2021. PNA’s latest account says the broader project was completed in 2023 and describes the September 2026 ceremony as the turnover of the facility’s operation and maintenance responsibilities. In other words, the latest event represents an important change in stewardship rather than simply the opening of a brand-new basin.
That distinction is important because the biggest challenge for large flood-control projects often begins after construction: keeping them functioning.
A JICA ex-post evaluation found overgrown vegetation as well as some sediment and garbage inside the Imus-area retarding structures during inspections in 2023. DPWH subsequently carried out large-scale cleaning and vegetation removal using heavy equipment in 2024. Despite those maintenance issues, the evaluation assessed operation and maintenance of the Imus River facilities as generally good and found no major sustainability concerns.
That experience underlines why the turnover is more than ceremonial. A basin with enormous theoretical storage capacity will only remain effective if drainage structures stay unobstructed, sediment is managed, vegetation is controlled and surrounding waterways continue to carry water as designed.
Cavite’s flood battle is much bigger than Imus
The Imus basin also forms only one part of a much larger attempt to manage flooding across one of the Philippines’ fastest-developing provinces.
Cavite has been pursuing additional retarding basins and river improvements, including facilities in General Trias and the broader Cavite Industrial Area Flood Risk Management Project, another JICA-supported initiative designed to protect highly urbanized and industrial communities. Provincial planning documents identify flood-control works affecting river systems that ultimately drain toward Manila Bay.
The larger project is particularly relevant to communities in Imus, Bacoor, General Trias, Kawit, Noveleta, Rosario and other low-lying areas, where prolonged rain, overflowing rivers and in some locations high tides can combine to worsen flooding. Planned interventions include retarding basins, improvements to waterways and drainage systems, and diversion or floodway infrastructure intended to move excess water more safely toward Manila Bay.
For DPWH, the Imus experience could also influence flood-control strategies elsewhere. Dizon said the facility could serve as a model for other areas, specifically citing the severe flooding experienced in Central Luzon after recent monsoon rains.
The real test comes with the next extreme storm
The numbers behind the Imus Retarding Basin are impressive: 35 hectares, 1.12 million cubic meters of storage and enough capacity to represent hundreds of Olympic swimming pools. Officials say the difference on the ground has already been substantial.
But flood resilience cannot be measured by storage capacity alone.
Cavite continues to urbanize, extreme rainfall remains a recurring threat, and downstream flooding involves entire river systems rather than a single structure. The basin can temporarily hold a huge volume of stormwater, but its long-term value will depend on maintenance, surrounding drainage infrastructure, river management and whether other components of Cavite’s broader flood-control network keep pace with development.
For residents who once watched floodwater climb toward their chests, that is ultimately the measure that matters—not how large the basin looks from above, but whether homes, roads and businesses stay dry when the next truly exceptional storm arrives.
WWC ONE MEDIA MJE
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