Metro Manila, with the total population of over 11.1 million in 2007, is the economic, political and cultural center of the Philippines. The Pasig Marikina River, having a total catchments area of 621 km², runs through the core of Metro Manila and flows into the Manila Bay. The river largely contributes to the flood in the metropolis caused by the over bank flow of floodwaters during heavy rains.

To find a solution to the flooding, as well as the environmental problems associated with the river improvement plan, studies have been conducted since 1988. The main component of this Project is the river channel improvement, which consist in the construction and rehabilitation of revetments, parapet walls/river walls and soil embankments, and the construction of the Marikina Control Gate Structure that will divert floodwaters from the upstream through the Mangahan Floodway to mitigate the flood damage in Metro Manila. At the present stage, the project is ongoing in multiple stages and the construction works are being financed through the Japan Bank for International Cooperation (JBIC) Loan.