As of December 2014, about 1.71 M ha or 56.6% of the total irrigable area in the Philippines have been developed for irrigation. Of these, 595,653 ha or 34.9% are under communal irrigation systems (CIS) representing around 20% of the 3.1 M ha potential irrigable areas. This illustrates an opportunity and the need to develop CIS for sustainable agriculture and food security.
Despite increasing investments, the firmed-up service area (FUSA) of CIS at the national level only increased by about 6% over the last 10 years. Likewise, despite massive rehabilitation efforts and funds for construction of new irrigation facilities, the increase in irrigation area is minimal. The national average cropping intensity of CIS is only about 130% due to over assessment at the design stage of the service area relative to what is actually irrigated and to available water supply.
This paper presents the common technical problems associated with the construction and O & M of CIS based on a study of 66 CIS in 11 provinces in Luzon. These CIS collectively cover a FUSA of about 332,769 ha, representing 58% of the total CIS in the Philippines as of 2013. The specific technical concerns examined include the sources of water, sedimentation, and design considerations from headworks to the distribution systems of CIS.