The Angat River Basin is located on the southeastern part of Central Luzon originating on the slopes of the Sierra Madre Mountains. It has a catchment area of 781 km2 and estimated annual run-off of 873 MCM collecting from the main tributaries of Matulid and Maputi rivers. The watershed area is bounded by Umiray River in the northeast, the Kanan River in the southeast, and the Marikina River in the south. The river defines a huge semi-elliptical curve of about 12 kilometers long near Sitio Bitbit in Norzagaray, Bulacan Province. At a few kilometers downstream, the river emerges from the mountain, flowing in a westerly course across the lowland plains of Bulacan before emptying its water into Manila Bay.
As early as 1904, the economic potential of the Angat River has been recognized and started a sustained and systematic effort to harness the economic potential of the river for the benefit of millions of people living in the central plain of Luzon. The development of Angat River started with the construction of Bustos Dam in 1926 for the purpose of irrigating about 27,000 ha of riceland in the Lower Angat River Basin and Pampanga River Delta.
The Angat Reservoir was originally conceived in 1939 as a run-of-river hydroelectric plant primarily for power development with a comparatively low capacity commensurate with the limited demand for power before the last world war. The rapid strides made in Post-War industrialization and the phenomenal growth of Manila and its neighboring communities had changed the concept of the development. The river was developed in its optimum capacity by the construction of a high dam in 1967 and impounds its water in the reservoir thus controlling and seasonally regulates the stream flow. Commissioning of the main power units No. 3 and No. 4 was in August 1968.
After the commissioning of auxiliary power unit No. 3 in October 1978, construction of the Ipo Diversion Dam was started in December 1978 and completed in January 1984. The Ipo Dam is located downstream of the Angat Multi-Purpose Dam below the confluence with the Ipo River. The purpose of the Ipo Dam is to divert water from Angat and Ipo rivers to the La Mesa Dam Reservoir and La Mesa Treatment Plant in Novaliches, Quezon City, Metro Manila.
At present, the Angat Reservoir is a multipurpose dam for hydropower, water supply, irrigation and flood control. It was constructed, and operated by the National Power Corporation (NPC). Although its primary uses are water supply and irrigation, its capacity for the main and auxiliary powerhouse is 200,000 kW and 18,000 kW, respectively. However, all these plant operations depend on the requirements of irrigation and water supply, which are released through the Main Turbines and Auxiliary turbines, respectively.
The reservoir supplies about 90 percent of raw water requirements for Metro Manila through the facilities of the Metropolitan Waterworks and Sewerage System (MWSS). It irrigates about 28,000 hectares of farmlands in the provinces of Bulacan and Pampanga under the service area of Angat Maasim River Irrigation System (AMRIS) of the National Irrigation Administration (NIA).
During the rainy season, the dam serves as a flood control facility where the reservoir serves as a buffer for the increased water inflow in the watershed catch basin. Because of its scenic landscape, the dam site is now a tourist attraction.
Water supply to Metro Manila depends largely upon the Angat River. Supply capacity of raw water at Ipo Dam amounts to 28.5 m3/sec (2,400 mld = 900 MCM). The Angat Water Supply Optimization Project (AWSOP) aims to increase the water supply capacity of MWSS by 15 m3/sec (1,300 mld = 470 MCM/Year) by applying the optimized usage of the release of the Angat reservoir, i.e. multiple use (power generation-irrigation-water supply) of water release with priority being given to water supply. AWSOP was initiated in 1989 and is still in progress. Later, it was found that unless some rearrangement/reallocation is made of multiple use of Angat Reservoir between NPC, NIA and MWSS, the 15 m3/sec as initially intended cannot be produced and the operation records indicated that only about 7 m3/sec (600 mld = 220 MCM/Year) were actually augmented.
The Umiray-Angat Transbasin Project (UATP) was conceived by MWSS as the second stage of the AWSOP and is under construction with a target completion within year 2000. The project will divert the discharge of about 12 m3/sec (1,000 mld = 370 MCM/Year) from Umiray River to Angat Reservoir. The Umiray River is located at the eastern part of the Angat Dam, flowing to the Pacific Ocean. Figure 2.3 shows the location of the existing water supply facilities of MWSS; Bustos Dam and Angat-Maasim Irrigation System service area of NIA.
The average annual rainfall in the Angat reservoir is 2,449 millimeters. The maximum and minimum annual rainfall observed is 4,919 mm in 1972 and 1430 millimeters in 1982, respectively. The extraordinary flood occurred on October 27, 1978 with 2,730 mm. of rainfall. The ten-year average inflow (1989-1998) is 1,724 MCM.
In 1997, the MWSS conducted a survey for the sedimentation and found out that for five (5) years, the sediment load increased by 5 cm. high.
Features of Angat Dam
Location
:
Brgy. San Lorenzo, Norzagaray, Bulacan
Coordinates
:
14°52’15” N
121°08’30” E
Name of the River
:
Angat River
Owner
:
National Power Corporation, and
National Irrigation Administration
Purpose
:
Multi-Purpose
Irrigation - 30,000 Has
Water Supply - 500 MGD
Power Generation - 246 MW
Flood Control - 63 MCM
History
Period of Construction
:
November 1961 – August 1968
Date of Operation
:
October 16, 1967
Drainage Area at Dam site
:
568 square kilometers
Dam
Type
:
Storage, Earth and Rock fill
Foundation
:
Solid Rock
Crest Elevation
:
El. 223.50 meters
Height
:
131 meters
Crest Width
:
8.75 meters
Crest Length
:
568 meters
Base width at maximum section
:
550 meters
Embankment
Rockfill
:
5,725,000 cubic meters
Impervious Fill
:
880,000 cubic meters
Filters
:
464,000 cubic meters
Dike
Rockfill
:
1,351,000 cubic meters
Impervious Fill
:
148,000 cubic meters
Filters
:
172,000 cubic meters
Reservoir
Usable Storage
:
850 million cubic meters
Design Flood Water Level
:
El. 219 m.a.s.l.
Normal High Water Level
:
212 m.a.s.l.
Spillway
Spill Elevation
:
El. 202 m.a.s.l.
No. of Gates
:
3 (12.5 meters x 15.0 meters)
Type of Gate
:
Tainter radial gates, hoist driven
Chain lift type
:
Elevation of top of gates
:
El. 217 m.a.s.l.
Design Flood
:
5,800 cubic meters/second
Diversion Tunnels
Tunnel No. 1
Dimension
:
7.60 meters dia. (modified horseshoe)
Length
:
607 meters
Inlet/Outlet Portal
:
El. 101.50/95.74 m.a.s.l.
Installation
:
Hower Valve to serve as low level by-pass irrigation and water supply.
Tunnel No. 2
Dimension
:
7.60 meters dia. (modified horseshoe)
Length
:
597.50 meters
Inlet/Outlet Portal
:
El. 98.30/95.89 m.a.s.l.
Installation
:
None. Completely plugged after diversion.
Power Intake and Penstock
Power Tunnel
Upstream Section
:
8.0 meters dia., concrete and steel lining
Downstream Section
:
7.0 meters dia., steel lining
Top Elevation
:
695.65 m.a.s.l.
Penstock
Type
:
Plate Steel embodied in concrete
Dimension
:
7.0 meters dia. split into two 4.50 meters dia. then into two 3.0 meters dia. leading to individual unit
Tailrace Tunnel
Dimension
:
8.50 meter dia. (horseshoe)
Length
:
1,800 meters.
Main Powerhouse
Floor Area
:
1,848 square meters, rectangular pit
Turbines
Type
:
Vertical shaft, Francis Turbine
Make
:
Toshiba
Number of Units
:
4 units
Generators
Capacity
:
55,555 KVA, 0.90 Power factor
Number of Units
:
4 units
Make
:
ASEA
Installed Capacity
:
200,000 kW (4 X 50,000 kW)
Auxiliary Powerhouse
Floor Area
:
432 square meters, rectangular
Turbines
Type
:
Vertical shaft, Francis Turbine
Make
:
Toshiba
Number of Units
:
6 units
Generators
Capacity
:
55,555 KVA, 0.90 Power factor
Number of Units
:
4 units
Make
:
ASEA
Installed Capacity
:
46,000 kW (3 X 6,000 kW, 1 x 10,000 kW, 1 x 18,000 kW)
Project Cost
:
P 315.344 Million (at current price level)
Construction By
:
Grogun, Inc. for diversion tunnels, dam foundation excavation and grouting
.
Paul Hardeman (Phil.) for dam, dike, spillway, power tunnel, powerhouse and power facilities but taken over by Filipino Engineers Syndicate, Inc
As early as 1904, the economic potential of the Angat River has been recognized and started a sustained and systematic effort to harness the economic potential of the river for the benefit of millions of people living in the central plain of Luzon. The development of Angat River started with the construction of Bustos Dam in 1926 for the purpose of irrigating about 27,000 ha of riceland in the Lower Angat River Basin and Pampanga River Delta.
The Angat Reservoir was originally conceived in 1939 as a run-of-river hydroelectric plant primarily for power development with a comparatively low capacity commensurate with the limited demand for power before the last world war. The rapid strides made in Post-War industrialization and the phenomenal growth of Manila and its neighboring communities had changed the concept of the development. The river was developed in its optimum capacity by the construction of a high dam in 1967 and impounds its water in the reservoir thus controlling and seasonally regulates the stream flow. Commissioning of the main power units No. 3 and No. 4 was in August 1968.
After the commissioning of auxiliary power unit No. 3 in October 1978, construction of the Ipo Diversion Dam was started in December 1978 and completed in January 1984. The Ipo Dam is located downstream of the Angat Multi-Purpose Dam below the confluence with the Ipo River. The purpose of the Ipo Dam is to divert water from Angat and Ipo rivers to the La Mesa Dam Reservoir and La Mesa Treatment Plant in Novaliches, Quezon City, Metro Manila.
At present, the Angat Reservoir is a multipurpose dam for hydropower, water supply, irrigation and flood control. It was constructed, and operated by the National Power Corporation (NPC). Although its primary uses are water supply and irrigation, its capacity for the main and auxiliary powerhouse is 200,000 kW and 18,000 kW, respectively. However, all these plant operations depend on the requirements of irrigation and water supply, which are released through the Main Turbines and Auxiliary turbines, respectively.
The reservoir supplies about 90 percent of raw water requirements for Metro Manila through the facilities of the Metropolitan Waterworks and Sewerage System (MWSS). It irrigates about 28,000 hectares of farmlands in the provinces of Bulacan and Pampanga under the service area of Angat Maasim River Irrigation System (AMRIS) of the National Irrigation Administration (NIA).
During the rainy season, the dam serves as a flood control facility where the reservoir serves as a buffer for the increased water inflow in the watershed catch basin. Because of its scenic landscape, the dam site is now a tourist attraction.
Water supply to Metro Manila depends largely upon the Angat River. Supply capacity of raw water at Ipo Dam amounts to 28.5 m3/sec (2,400 mld = 900 MCM). The Angat Water Supply Optimization Project (AWSOP) aims to increase the water supply capacity of MWSS by 15 m3/sec (1,300 mld = 470 MCM/Year) by applying the optimized usage of the release of the Angat reservoir, i.e. multiple use (power generation-irrigation-water supply) of water release with priority being given to water supply. AWSOP was initiated in 1989 and is still in progress. Later, it was found that unless some rearrangement/reallocation is made of multiple use of Angat Reservoir between NPC, NIA and MWSS, the 15 m3/sec as initially intended cannot be produced and the operation records indicated that only about 7 m3/sec (600 mld = 220 MCM/Year) were actually augmented.
The Umiray-Angat Transbasin Project (UATP) was conceived by MWSS as the second stage of the AWSOP and is under construction with a target completion within year 2000. The project will divert the discharge of about 12 m3/sec (1,000 mld = 370 MCM/Year) from Umiray River to Angat Reservoir. The Umiray River is located at the eastern part of the Angat Dam, flowing to the Pacific Ocean. Figure 2.3 shows the location of the existing water supply facilities of MWSS; Bustos Dam and Angat-Maasim Irrigation System service area of NIA.
The average annual rainfall in the Angat reservoir is 2,449 millimeters. The maximum and minimum annual rainfall observed is 4,919 mm in 1972 and 1430 millimeters in 1982, respectively. The extraordinary flood occurred on October 27, 1978 with 2,730 mm. of rainfall. The ten-year average inflow (1989-1998) is 1,724 MCM.
In 1997, the MWSS conducted a survey for the sedimentation and found out that for five (5) years, the sediment load increased by 5 cm. high.
Features of Angat Dam
Location
:
Brgy. San Lorenzo, Norzagaray, Bulacan
Coordinates
:
14°52’15” N
121°08’30” E
Name of the River
:
Angat River
Owner
:
National Power Corporation, and
National Irrigation Administration
Purpose
:
Multi-Purpose
Irrigation - 30,000 Has
Water Supply - 500 MGD
Power Generation - 246 MW
Flood Control - 63 MCM
History
Period of Construction
:
November 1961 – August 1968
Date of Operation
:
October 16, 1967
Drainage Area at Dam site
:
568 square kilometers
Dam
Type
:
Storage, Earth and Rock fill
Foundation
:
Solid Rock
Crest Elevation
:
El. 223.50 meters
Height
:
131 meters
Crest Width
:
8.75 meters
Crest Length
:
568 meters
Base width at maximum section
:
550 meters
Embankment
Rockfill
:
5,725,000 cubic meters
Impervious Fill
:
880,000 cubic meters
Filters
:
464,000 cubic meters
Dike
Rockfill
:
1,351,000 cubic meters
Impervious Fill
:
148,000 cubic meters
Filters
:
172,000 cubic meters
Reservoir
Usable Storage
:
850 million cubic meters
Design Flood Water Level
:
El. 219 m.a.s.l.
Normal High Water Level
:
212 m.a.s.l.
Spillway
Spill Elevation
:
El. 202 m.a.s.l.
No. of Gates
:
3 (12.5 meters x 15.0 meters)
Type of Gate
:
Tainter radial gates, hoist driven
Chain lift type
:
Elevation of top of gates
:
El. 217 m.a.s.l.
Design Flood
:
5,800 cubic meters/second
Diversion Tunnels
Tunnel No. 1
Dimension
:
7.60 meters dia. (modified horseshoe)
Length
:
607 meters
Inlet/Outlet Portal
:
El. 101.50/95.74 m.a.s.l.
Installation
:
Hower Valve to serve as low level by-pass irrigation and water supply.
Tunnel No. 2
Dimension
:
7.60 meters dia. (modified horseshoe)
Length
:
597.50 meters
Inlet/Outlet Portal
:
El. 98.30/95.89 m.a.s.l.
Installation
:
None. Completely plugged after diversion.
Power Intake and Penstock
Power Tunnel
Upstream Section
:
8.0 meters dia., concrete and steel lining
Downstream Section
:
7.0 meters dia., steel lining
Top Elevation
:
695.65 m.a.s.l.
Penstock
Type
:
Plate Steel embodied in concrete
Dimension
:
7.0 meters dia. split into two 4.50 meters dia. then into two 3.0 meters dia. leading to individual unit
Tailrace Tunnel
Dimension
:
8.50 meter dia. (horseshoe)
Length
:
1,800 meters.
Main Powerhouse
Floor Area
:
1,848 square meters, rectangular pit
Turbines
Type
:
Vertical shaft, Francis Turbine
Make
:
Toshiba
Number of Units
:
4 units
Generators
Capacity
:
55,555 KVA, 0.90 Power factor
Number of Units
:
4 units
Make
:
ASEA
Installed Capacity
:
200,000 kW (4 X 50,000 kW)
Auxiliary Powerhouse
Floor Area
:
432 square meters, rectangular
Turbines
Type
:
Vertical shaft, Francis Turbine
Make
:
Toshiba
Number of Units
:
6 units
Generators
Capacity
:
55,555 KVA, 0.90 Power factor
Number of Units
:
4 units
Make
:
ASEA
Installed Capacity
:
46,000 kW (3 X 6,000 kW, 1 x 10,000 kW, 1 x 18,000 kW)
Project Cost
:
P 315.344 Million (at current price level)
Construction By
:
Grogun, Inc. for diversion tunnels, dam foundation excavation and grouting
.
Paul Hardeman (Phil.) for dam, dike, spillway, power tunnel, powerhouse and power facilities but taken over by Filipino Engineers Syndicate, Inc
WTF!! a crack on that DAM-n?
visit this website: http://www.gmanews.tv/largevideo/latest/47746/bulacan-residents-worried-about-crack-in-angat-dam
as you can see, I am a concern citizen of the Philippines, please we need, as in immediately, take actions to save mother earth, eventhough im just a normal kid, or student i should say... I still got a little tremble on what might the nature do to us....
so long..
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