Study Area

The study area is placed to the entire catchment area of Pampanga river basin covering an extent of 10,434km2, which is broadly divided into three sub-basins, namely: (a) Pampanga main river basin with its catchment area of 7,978 km2, (b) Pasac river basin with 1,371 km2 and (c) Angat river basin 1,085 km2 (refer to General Map). These three sub-basins originate in the different mountainous areas and have the separate river mouths to the Manila Bay, while they are interconnected by channels and their water resources management works are mutually and closely related.

The study area spreads over the administrative area of eleven (11) provinces and 90 cities/municipalities. The substantial part of the study area (about 95%) is, however, within the boundary of four provinces, namely, Nueva Ecija, Tarlac, Pampanga and Bulacan.  The remaining fringe area (about 5%) is a part of other seven provinces, Aurora, Zambales, Rizal, Quezon, Pangasinan, Bataan and Nueva Vizcaya.

There exist the water conveyance systems between the internal and external parts of the study area.  The typical conveyance systems are as enumerated below:

(1) The Casecnan Diversion System, which coveys the water from Casecnan River (a tributary of Cagayan River) to Pantabangan dam reservoir located in the northern part of Pampanga river basin,

(2) The Umiray-Angat Diversion System, which coveys the water from Umiray River to Angat dam reservoir located in the south-eastern part of the Angat river basin and

(3) The water conveyance from Angat dam reservoir toward Metro Manila and its adjacent several cities/municipalities in Bulacan Province (such as Meycauayan, Obando, Malilao and San Jose Del Monte) for the sake of domestic water use.

The above Casecnan and Umiray river basins are out of the study area.  However, these river basins are the important water sources for the study area.  Likewise, Metro Manila and its adjacent cities/municipalities in Bulacan Province are out of the study area but about 90% of the domestic water use in these areas depends on the supply from Angat dam reservoir located in the study area.  Under these conditions, the water demand and supply balance is made taking these external water supply and demand areas into account.