The river originates in the Cordillera Mountains, initially flows from north to south, divides into several channels in the flat central plain of Luzon and meanders westerly through the provinces of Pangasinan and Tarlac before emptying into Lingayen Gulf.

SRPC substantially completed the SRMP at midnight, February 14, 2003, at which time its peaking power, irrigation, flood control and enhanced water quality benefits became available to the surrounding regions, which include the Northwest Luzon Economic Growth Quadrangle.

The SRMP can provide year-round irrigation benefits for 708 square kilometers of farmland downstream of the dam with a partially diversified crop during the dry season, mostly in Pangasinan, but including parts of Nueva Ecija and Tarlac.

The SRMP produces a marked attenuation (reduction) in the perennial flooding of the Agno River affecting at least 16 Pangasinan and Tarlac towns.

The SRMP improves the quality of the water in the Lower Agno River via a proactive integrated watershed management plan (IWMP) and by trapping sediments caused by erosion and by such other sources as small-scale mining.