San Manuel, Pangasinan

The San Roque Dam has a height of 200 m above the existing river valley floor. It is a central clay-core rockfill dam with a compacted fill volume totaling nearly 40 million cubic meters. At its nominal crest of El. 295.0, the Dam length is 1,130 m. Two meters of additional fill (camber) have been placed at the dam crest to allow for any expected minor settlement of the structure. The Dam consists of combined earth/gravel fill and rockfill shell zones, filter, drain and transition zones. The impermeable core is a clay gravel blend.  Three grouting/drainage galleries provided for inspection and maintenance purposes are located in the dam foundation. The majority of the 1,200 meters of gallery length are 3 m wide by 4.5 m high with shotcrete lining. The section located at the lowest level of the foundation is reinforced with a formed concrete lining to accommodate potentially higher ground water pressures. Access to the galleries is provided by for adits, two on each side of the downstream abutments.

  • commissioned in 2003
  • 200-meter high & 1.2-km long embankment
  • largest hydro installation in SE Asia
  • 3rd largest in entire Asia
  • 12th largest dam in the world

Hydrology

Drainage Area

1,250 km2

Average Flow

83.6 cms

Design Flood - PMF

13,000 cms

Dam

Type

Central clay core rockfill dam

Maximum Height

290 m

Crest Level

El. 295 (plus 2 m chamber)

Fill Volume (including cofferdams)

40 MCM (approximate)

Dam Length

1,130

Slope

2h:1v (upstream & downstream)

Crest Width

12 m