In terms of augmenting irrigation for existing land and increasing serviceable new areas for the National Irrigation Authority (NIA), the project shows more than a 15-percent economic rate of return for the Philippine government. In terms of rice importation, this would save the government some $90 million a year.
The Casecnan project, the first build-operate-transfer (BOT) irrigation project of the government and considered as a landmark project for the Department of Agriculture, diverts water from the Casecnan and Taan Rivers in Nueva Viscaya through a 26-kilometer tunnel running deep below the Caraballo mountain, and to the Pantabangan Reservoir.
It will significantly contribute to enhancing the irrigation of approximately 102,000 hectares and opening up some 35,000 hectares of new rice fields in central Luzon. This would benefit some 27,000 farmers, translating to an additional rice production of 302,000 tons a year.
The project was initiated in May 1993 in response to an expected shortfall in irrigation systems brought about by the Mt. Pinatubo eruption. By augmenting the water supply of the Pantabangan Reservoir, the Casecnan project is estimated to bring over 66 million cubic meters of water to a total of 132,000 hectares of drought-prone farmlands each month.
Water flowing through the underground tunnel is harnessed through a 140-MW power plant before being released to the Pantabangan Reservoir. NIA sells the electricity directly to the National Power Corp.
The Casecnan project was completed in December 2001 at a cost of P700 million. The whole facility has a life of 50 to 100 years.