A NUMBER of large dams in the Philippines, built primarily as a water reservoir for domestic and agricultural use, have multiple uses, from hydropower and flood control to tourist spots.
There’s the Wawa Dam in Montalban, Rizal, and the Magat Dam at the boundaries of Ramon, Isabela and Alfonso Lista, Ifugao province.
The Ambuklao Dam in Benguet is also known for its aesthetic beauty. Hikers on Mount Pulag stop near the dam to enjoy the scenery.
The La Mesa Dam, which is nearest to Metro Manila, offers city residents an opportunity to commune with nature and with modern-day amenities like swimming pools.
There are several hydroelectric power plants served by large dams. These dams include the following: Agusan, Angat, Binga, Bustos, Caliraya, Casecnan, Lumot, Magat, Pantabangan, Pulangi and San Roque.
Because of their flood-control functions, the Philippine Atmospheric, Geophysical and Astronomical Services Administration also monitors the water level in a good number of dams, namely, Angat, Ambuklao, Ipo, Binga, Caliraya, La Mesa Magat and Pantabangan.
METRO Manila’s over 12 million people depend on clean-water supply from the Angat Dam, a 60-year-old water reservoir. Angat Dam supplies about 95 percent of raw water requirements for Metro Manila and some parts of Greater Manila Area through the facilities of the Metropolitan Waterworks and Sewerage System (MWSS). Water from Angat flows to Ipo Dam and La Mesa Dam, from which treated water flows to household consumers through two private water contractors—Manila Water Co.Inc. and Maynilad Water Services Inc.
Aside from providing domestic water supply, water from Angat irrigates about 28,000 hectares of farms in the provinces of Bulacan and Pampanga.
The dam, however, is heavily silted and concerns have been raised over the integrity of the structure, given that it is more than 60 years old. With the country prone to strong earthquakes, there is also concern over a possibility of the dam collapsing, especially in the case of a 7.2-intensity earthquake.
MWSS Administrator Reynaldo V. Velasco considers water security as a matter of national security.
A member of the Philippine Military Academy Class of 1971 and one of the top police officials prior to his appointment to the MWSS, Velasco has emphasized on several occasions the importance of securing the country’s water resources, particularly the water reserve in Angat Dam.
MWSS sources 95.6 percent of its water supply from the Angat and Umiray rivers, and 4 percent from the Laguna de Bay.
The remaining supply, approximately 0.4 percent, comes from groundwater sources. He said these are reasons enough to reduce MWSS’s dependency on Angat Dam, which supplies most of the water in Metro Manila.
Velasco added securing the Angat Dam and other water facilities against terrorist threat is one of the many focus of his leadership as MWSS chief.
Moreover, he underscored the need to rehabilitate the country’s degraded ecosystem to protect the country’s freshwater resources.
THE Philippines, Velasco said, is faced with the sad fact that the country’s forest cover decreased by 328,682 hectares from the 7.17 million hectares in 2003 to 6.84 hectares in 2010, or an annual forest cover loss of 46,954 hectares.
He cited the importance of implementing and sustaining a massive reforestation activity, such as the National Greening Program, to ensure water resources.
Velasco said under his watch, the MWSS will work with other government agencies to rehabilitate, protect and conserve six of the 143 critical watersheds—Angat, Ipo, La Mesa, Umiray, Marikina and Laguna Lake watershed—to ensure water supply for Metro Manila.
The MWSS is pushing for the Annual Million Tree Challenge, a reforestation project to benefit the six critical watersheds. The target is to plant a million trees until the duration of the Duterte administration.
The ongoing project is backed by nongovernmental groups like the Philippine Waterworks Association and Wild Bird Photographers of the Philippines, among others, and the local government units of General Nakar, Quezon, and Bulacan province.
IN an interview, Velasco told the BusinessMirror of the various ongoing initiatives the Duterte administration is undertaking to prepare the country from the worst-case scenario, such as in the event of the long dry season resulting in drought and a water-
The worse-case scenario is an earthquake that could cause the Angat Dam to collapse, thereby inadvertently wasting the reserved water in Bulacan.
While the dam is undergoing structural rehabilitation, he said, the government is “prudently looking at ways” to reduce dependency on Angat and enhance water security and sustainability through the Kaliwa Dam and other projects that will boost the supply of water for Metro Manila and nearby provinces.
Velasco described the construction of the Kaliwa Dam as a “necessity” to ensure alternative supply of clean, drinking water for domestic use in case the Angat Dam is rendered ineffective because of its deteriorating status.
The dam is already silted, reducing its capacity to impound more water. The dam is also prone to collapse in case of a strong earthquake, which, he said, may happen anytime.
“Right now, our supply from Angat is enough to support our need. But in the next few years, with the growing population and the impact of climate change, it may no longer suffice,” Velasco told the BusinessMirror. “What we are preparing for is a natural disaster that may endanger our main and only water source. In case of the ‘Big One,’ this early, we must find other sources of clean water that will be enough for the next 30 to 50 years.”
Even with the construction of the Kaliwa Dam, Velasco said he will not recommend the decommissioning of the Angat Dam, saying it may still serve its purpose. He added the government considers the ongoing rehabilitation of the dam as being done by “experts.” The rehabilitation, Velasco explained, is expected to reinforce the structure for the dam to last longer and provide water and irrigation as it has done in the past decades.
“No, not yet. We will still have some use for it,” he said. Velasco was referring to the Angat Dam and Dyke Strengthening Project to ensure the Angat Dam’s stability and safety to withstand the potential risk posed by possible seismic activity associated with the West Valley Fault.