3rd GEOSS Asian Water Cycle
Symposium
December 2-4, 2007
Beppu, Oita, JapanPAMPANGA RIVER BASIN(Angat Basin)

Demonstration ProjectFlaviana Hilario
Weather Services Chief, Climatology and Agrometeorology Branch
PAGASA/DOST•The principal river, Angat River, originates from thewestern flank of the Sierra Madre Mountains. It then cuts
through the mountainous terrain in a westerly direction tothe dam site.
•The elevation within the watershed rises to a maximumof 1,115 meters at the Sierra Madre Mountain range and islowest at the dam site at 100 meters.
•It has three major tributaries, namely, the Talaguio,
Catmon and Matulid Rivers. The Angat Watershed has amoderate to intensive forest cover and has a drainage
area of about 568 square kilometers, which receives anaverage annual rainfall of about 4,200 millimeters.
•The Angat Dam is a rockfill dam with a spillway equippedwith three gates at a spilling level of 219 meters. Itsstorage capacity is about 850 million cubic meters. Water
supply to the MWSS is released through five auxiliary
turbines where it is diverted to the two tunnels going tothe Ipo Dam.

ANGAT BASIN

Angat Dam
The Angat Reservoir and Dam are located at theAngat River in San Lorenzo, Norzagaray, Bulacan.
The facilities were constructed from 1964 to 1967
and have been operational since 1968. They havemulti-purpose functions:
1. To provide irrigation to about 31,000 hectares ofland in 20 municipalities and towns in Pampanga
and Bulacan;
2. To supply the domestic and industrial waterrequirements of residents in Metro Manila;
3. To generate hydroelectric power to feed the Luzon
Grid; and4. To reduce flooding to downstream towns andvillages.

M ap u ti
T alag uio

M atu lidN o rzag aray
Ip od am

A ng a tdam

A ngat B asin

600600500500

400400300

300

2002001001000
1 2 3 4 5 6 7 8 9 10 11 120
1 2 3 4 5 6 7 8 9 10 11 12Maputi

TalaguioMonthly distribution ofrainfall in the Angat
watershed

MatulidAngat
Dam

600

600
500

500

400
400300
300

200
200

100

10000
1 2 3 4 5 6 7 8 9 10 11 12

1 2 3 4 5 6 7 8 9 10 11 12

Monthly Mean Rainfall of Angat Watershed (1986-2003)
497.2500.0465.1

450.0
411.8
400.0

374.6

Rainfall (mm)

350.0

328.8

327.0

300.0

272.5
243.3

250.0
200.0
150.0
100.0

75.2

66.6

67.2

75.0

FebMar

Apr

50.0
0.0

JanMayJunJulAug

Sep

Oct

Nov

Monthly Maximum & Minimum Rainfall in Angat Watershed (1986-2003)
1200.0Maximum
Minimum

1033.01000.0918.7
811.3

R a in fa ll ( m m )

800.0

817.0

649.8

614.0

600.0

635.7

477.7
400.0

200.0

184.3

215.5

243.8

285.3
212.8

183.8

170.0

102.3
0.0

11.0
Jan

3.7
Feb

6.3
Mar

24.8
Apr104.058.5

52.0

7.5
MayJunJulAug

SepOctNovDec

Dec

Comparison Between the Actual RR (1997) and Mean RR
600.0215

Meal

RWL

500.0

205

400.0

195300.0185200.0175100.0

1650.0155
1234567891011R W L (m A M S L )R a in fa ll (m m )Actual (1997)

12Annual Total RR = 1679 mm
RWL, Dec 31, 1997 = 183.54 m (LRC = 207.3 m)

Comparison Between Actual RR (1998) and Mean RR
700.0
ActualMean

RWL

215
205

500.0

195400.0185300.0
200.0175100.0

1650.0155123456789Annual Total RR = 2460 mm
RWL, Dec 31, 1998 = 216.49 m (LRC = 207.3 m)

101112R W L (m A MS L)

R ainfall (mm)600.0

Angat Dam Average Monthly Elevation
RESERVOIR ELEVATION (1968 - 1999)
215.00210.00209.21208.03206.23205.00ELEVATION (M. AMSL) ------>

204.21200.00199.36198.88195.00193.76193.46190.00189.17185.00188.60184.78M o nthly A verage

184.03180.00175.00170.00
JA N

FEB

M AR

APR

M AYJUNJULMONTH ------>

A UG

SEP

OCTNOVDEC

Angat Dam Water Level Oct. 17, 2007

Thank You!

“tracking the sky . . . helping the country”