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Monday, March 23, 2020

Maynilad Tour: Angat, Ipo and La Mesa Dam

I had a privilege of touring Angat, Ipo and La Mesa Dam, through Maynilad last month. 

Our first stop was the Maynilad office where we received a quick briefing and some reminders about the tour. There was supposed to be a boat ride, which excited me a lot (until I saw the mini boat) but more on that later.
We then drove 2 hours to Angat Dam which was located in Norzagaray, Bulacan, and we had a great view of the Angat Dam from the Angat Rainforest Eco Park viewdeck. 

There we met up with Maynilad’s Water Source Head Rodel Tumandao who explained the intricacies of our water distribution system.

Angat Dam is owned and operated by the Angat Hydropower Corporation (AHC). It was constructed in 1965 and commissioned in 1968. About 91% of Maynilad’s raw water supply comes from Angat Dam in Norzagaray, Bulacan. The rest comes from Laguna Lake.
The Angat Dam is a multi-purpose dam. It is used for power generation, for irrigation through the National Irrigation Authority (NIA), and for domestic water supply through the Metropolitan Waterworks and Sewerage System (MWSS).
He also adds that Angat River has “Class A” water meaning it is the best and easiest type of water to treat because it has the least impurities.

From Angat Dam, raw water flows downward to the much-smaller Ipo Dam and, eventually, to the Novaliches Portal where the water is divided between the two private water concessionaires of the MWSS--i.e., Manila Water for the East Zone concession, and Maynilad for the West Zone concession. Maynilad gets 60% share because of its bigger customer base. While the two concessionaires share the raw water supply coming from Angat and Ipo Dams, only Manila Water gets raw water from La Mesa Dam.

The entire Angat Watershed area is about 62,000 hectares, while IPO watershed is at 6,600 hectares.
He then explained why Maynilad had to implement this rotational water service interruption schedule.

Maynilad’s Water Source Head Rodel Tumandao

According to him, the National Water Resources Board (NWRB) is the government agency responsible for determining the allocation of raw water supply from Angat Dam for MWSS and NIAThe normal allocation for MWSS is 48 cubic meters per second (cms). This supply is shared among residents of Metro Manila and the nearby provinces of Cavite, Rizal and Bulacan.

Last June 2019, the NWRB reduced raw water allocation for the MWSS in an effort to preserve the remaining water in Angat Dam, which plunged to below-critical levels due to scant rainfall.

So while at present, the water level in Angat Dam is above its minimum operating level, the NWRB still decided to retain the reduced allocation for MWSS (currently at 42 cms). This is because the water level is still lower than ideal, and NWRB wants to ensure that there will still be enough water by the time the summer months arrive.

When Maynilad is given less than its usual raw water allocation, it is constrained to maximize the limited supply by rotating it to the different areas within its concession. This is to ensure that all customers will have an opportunity to store water, even within only a few hours daily.

The duration of service interruptions per area is dependent on the hydraulic configuration of the pipelines. This means that some areas will experience longer or shorter service interruptions owing to their location (i.e., areas that are low in elevation, are near Maynilad’s reservoirs and pumping stations, and are conduits to reach fringe areas will naturally have shorter service interruptions).  

Certain factors cause the delay of supply resumption following a service interruption. These include the volume of withdrawal from the pipelines as customers start getting water, the topography of an area (low-lying areas feel the supply resumption earlier than those in highly elevated areas), and the actual raw water supply that enters Maynilad’s treatment plants for the day (lower volume received means less water for distribution).

The implementation of daily rotational service interruptions will be in effect for as long as the raw water allocation given to Maynilad from Angat Dam is below its requirement. Per NWRB, reduced allocations will remain in effect until June 2020. Continuous monitoring of Angat and lpo Dams are being done to check if the water levels improve enough to raise the allocation.
Our 2nd stop was the Ipo Dam, which diverts water from Angat Dam to the Novaliches Portal. Maynilad’s share of the raw water thereafter flows to its La Mesa Water Treatment Plants in Quezon City. The air there is fresh  plus the  place is instagramable and it has the cleanest dam that I have seen up close.
With summer fast approaching Maynilad is encouraging its customers to do their part in conserving water as historically, consumer demand for water increases during the hot season. This, coupled with scant rainfall over the Angat and Ipo Dams, might force the NWRB to further reduce raw water allocation for the MWSS. Such reduction would mean longer daily rotational water service interruptions for customers of the concessionaires.
Water Supply Operations Head of Maynilad, Engr. Ronald Padua

Back at the Maynilad office, we met with the Water Supply Operations Head of Maynilad, Engr. Ronald Padua. I learned during the tour that Maynilad operates and maintains 4 water treatment plants, 22 wastewater plants, 36 pumping stations. 32 reservoirs, 28 in-Iine boosters. and has laid 3.137 kilometers of water pipelines since 2007, bringing the total of water pipelines laid to 7,713 kilometers. Whew!

To alleviate the impact of the reduced allocation during summer 2020, Maynilad has been implementing mitigating measures since last year--measures that would essentially add water supply for distribution to its 9.7 million customers despite the shortage from Angat and Ipo dams. These include optimizing its Putatan Water Treatment Plant 1 and commissioning its Putatan Water Treatment Plant 2 to get water from Laguna Lake and produce 300 million liters per day of additional water supply, reactivating deep wells (during the summer months only, as long-term use of deep wells may cause land subsidence), purchasing modular treatment plants that will tap rivers in Cavite, and deploying 69 mobile tankers and 32 stationary water tanks.

In addition to these, the company is also coordinating with the different government agencies, including MWSS, Bureau of Soils and Water Management (BSWM), Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), and Philippine Air Force (PAF) regarding the cloud-seeding operations.

I learned during the tour that cloud-seeding operation is not simple, and for it to work, rain must exactly be in Angat Dam.While Maynilad's mitigating measures will help to ease the impact of the water shortage this coming summer 2020, the ultimate solution is to develop an additional raw water source-- one of the same scale as Angat Dam. 

The government through the MWSS, has lined up several prospective sources, and is working to fast-track their development to ensure long-term water security and reliability for water consumers in Metro Manila and nearby provinces. 

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