The Agno River Basin

This is the map of tributaries and flood-prone areas around the Agno River basin from Pagasa’s Flood Forecast Branch. The text below the map gives general information about the Agno River Basin and its environs.

Fast Facts:

• Drainage area: 5,9252 sq. km
• Third largest river in Luzon, fifth in the Philippines
• Length of river system from source to mouth: 270 km (90 km of which runs through mountainous terrain and canyons)
• Average elevation: 2,000 meters above sea level (masl)

Flooding:

• Characterized by mountainous topography
• Flood runoff: 6,654 million cubic meters (annual estimation)
• Average annual rainfall:
  • 2,000 mm (in Tarlac portion)
  • 4,000 mm in upper reaches of Agno River
• Flood target areas:
  • The entire Pangasinan Plain
  • Municipalities in Pangasinan:
    • Dagupan
    • Lingayen
    • Bugallon
    • Sta. Barbara
    • Bayambang
    • Rosales
  • Central part of Tarlac
  • Municipalities in Tarlac:
    • Gerona
    • Paniqui
    • Moncada

Connecting water ways and nearby mountain ranges

• Source of water: the Cordillera Mountains
• Mouth of the basin: Lingayen Gulf (Pangasinan)
• Pangasinan plain
  • A vast alluvial fan and delta formed by the Agno River
  • Constitute the rice granary of Central Luzon
• Principal tributaries:
  • Pila River
  • Camiling River (Tarlac)
  • Tarlac River – main branch of the Agno River
    • Source: Mount Pinatubo Volcano (elevation of 1,745 m)
  • Ambayoan River
• Poponto Swamp (near Bayambang, Pangasinan)
  • Joins the Tarlac river and the Agno River
  • Area: 25 sq. km.
  • Retains flood waters from the Tarlac River

Source: Pagasa flood forecast branch