Irrigation in Asia, including the Philippines, is becoming increasingly vulnerable to water scarcity, a consequence of rising population and increased demands from household and industrial consumption. According to the Philippines’ Second National Communication to the UNFCCC, watershed forest reserves make up 1.56 million hectares of land area (5% of the country’s total), with watersheds acting as the most significant source of water for the agricultural, industrial and commercial sectors. Water distribution across the county is variable given the difference in climate and rainfall. The Philippines annual water availability per year stands at 1,900 cubic meters per person, which is the second lowest of the southeast Asian countries and lower than global average. If current trends follow, areas of the Philippines could face water scarcity. Climate change could impact hydrological processes with significant effects on numerous aspects of water resources, including streamflow, domestic water supply, irrigation, aquifer depth and recharge as well as water quality such as saline intrusion. The water sector is particularly vulnerable to the effects of typhoons. In addition, droughts have considerable consequences for hydropower generation, with major power generation losses occurring as a result of decreased water supply.
This section provides insights into projected climate change impacts on various hydrological indicators.