Tigman-Hinagyanan-Inarihan River Irrigation System (THIRIS): Sustaining Lives, Empowering People

By Ed G. Yu

Built in the early 1980’s, THIRIS, formerly known as the Naga-Calabanga Irrigation Project under the then National Irrigation Administration Bicol River Basin Irrigation Development Project (NIA-BRBIDP) sought to address rural poverty in the four towns of Calabanga, Bombon, Magarao, Canaman, all in the province of Camarines Sur.

Funded by a $41 million loan from the Asian Development Bank (ADB),  NIA constructed two new dams, the Tigman and Hinagyanan Dams, and repaired one of the oldest dams in the Bicol region, the Inarihan Dam, all located in the town of Calabanga.  Aside from the dams, other major irrigation structures and facilities like main canals, siphons, check gates, service roads, flood control structures and sea walls were constructed.

Upon completion in  1989,  THIRIS irrigated some 3,542 hectares of rice farms in the four towns earlier mentioned, broken down as follows:  Calabanga, 1615 hectares; Bombon, 538 hectares; Magarao, 780 hectares, and Canaman 609 hectares.

This irrigation system serves some 3,765 farmers organized into nine irrigators associations (IA), namely: Hi-Farm IA; Calabanga Division A IA; Calabanga Divison B IA; Bombon-Quipayo IA; Centro-Magarao IA; Bombon-Habagatan IA; Canaman-Magarao IA; and Franc-Bel-Cas IA.

Since its completion in 1989 up to 2012, only minor repair works  in the irrigation system were carried out due to funding constraints. This resulted to the deterioration of the irrigation structures and facilities, which affected and reduced irrigation service from the original 3,542 hectares of firmed up service area to an actual irrigated area of 2,500 hectares at present.

Closing the gap in the original service area and present actual irrigated area of THIRIS is the primary purpose why the Participatory Irrigation Development Project (PIDP) is implemented in 2013. This  World Bank-funded initiative has an overall development objective of  improving irrigation delivery  on a financially and technically sustainable basis that will contribute to increase agricultural production and productivity among THIRIS’ farmer-beneficiaries.

THIRIS is one of the 58 National Irrigation Systems (NIS) nationwide subject to rehabilitations under PIDP.   The cost of THIRIS improvement is P87.5 million.

Among the major items of work being undertaken in THIRIS are: replacement of the main steel gates of the three dams and installations of electronic lifting mechanism for the gates; 50 kilometers of road resurfacing of the service roads; construction of 36 units of steel gates of outfall structures for drainage purposes; replacement of 55 units of turnout gates; 20 kilometers of concrete canal lining of portions of main and lateral canals; grouted riprapping; construction of eight units of core shelters for informal settlers formerly living along the main canal; repair of existing office buildings; and other related works.

As of June 30, 2016, the physical accomplishment of the project was 51.27 percent.  The revised target date of completion of the project is Nov. 13, 2016.

Without a doubt, the operation of THIRIS in the four towns of the 3rd District of Camarines Sur has substantially improved and sustained the lives of farmers in the area. It has also empowered farmers through the IAs, which act as the main partner of NIA in the operation and maintenance of the irrigation system.