Table of Contents
Volume 23. Muntinlupa Sub-Basin ...... 3 Geographic Location ...... 3 Political Boundary ...... 4 Land Cover ...... 5 Sub-basin Characterization and Properties...... 7 Drainage Network / Properties ...... 7 Sub-sub basin Properties ...... 9 Water Quantity ...... 10 Streamflow ...... 10 Water Balance ...... 11
LIST OF FIGURES Figure 23-1 Geographical Map ...... 3 Figure 23-2 Political Map ...... 5 Figure 23-3 Land Cover Map ...... 6 Figure 23-4 Drainage Map ...... 8 Figure 23-5 Sub-sub basin Map of Muntinlupa Sub-basin ...... 9 Figure 23-6 Streamflow for, 1990-2004 ...... 11 Figure 23-7 Water Balances based on model simulation, 1990-2004 ...... 12
LIST OF TABLES Table 23-1 Geographic extents ...... 4 Table 23-2 Municipalities and Barangays Covered ...... 4 Table 23-3 Population, 2007 ...... 5 Table 23-4 Land Cover ...... 6 Table 23-5 Some Relief Features and Other Geo-Morphological Parameters ...... 7 Table 23-6 Muntinlupa Sub-sub basin properties ...... 10 Table 23-7 Streamflow Data, 1990-2004 ...... 10 Table 23-8 Yearly Water Balances based on model simulation (mm) ...... 11
Technical writer Mr. Dennis A. Tiongson
Technical editors Ms. Adelina C. Santos-Borja Engr. Emiterio C. Hernandez Officer-In-Charge Officer- In Charge Resource Management and Development Officer Project Development Management and Evaluation Division
Map production Mr. Neil V. Varcas
Volume 23. Muntinlupa Sub-Basin
Geographic Location The City of Muntinlupa is located 22 kms south of Metro Manila and is easily accessible from the nearby provinces such as Laguna, Batangas, Cavite and Quezon. It is bounded on the Northwest by Paranaque City, on the West by Las Pinas City, on the Southwest by Cavite, on the South by Laguna and on the east by the Laguna de Bay. It has a total land area of 4384.576 hectares.Figure 23-1 illustrates the geographic location and boundary of the Muntinlupa sub- basin in the Laguna de Bay.
Source: LLDA GIS Figure 23-1 Geographical Map
There are seven watersheds whose names were derived from the name of the rivers or the name of the barangays where they are situated based on the topographical map. These are Sucat, Buli, Cupang, Bayanan, Balimbing, Magdaong, and Tunasan watersheds. They are bounded by Laguna Lake on the east, Alabang Heights Village on the northwest and extended to Victory Homes and Chrysanthemum on the southwest, Susan Heights, Magsaysay and Sampaguita on the south, and San Pedro on the southwest.
Muntinlupa City is composed of nine barangays, namely, Alabang, Ayala-Alabang, Bayanan, Buli, Cupang, Poblacion, Putatan, Sucat, and Tunasan. Tunasan occupies the greatest percentage in terms of area, followed by Alabang, Ayala-Alabang and Putatan.
It is noted that only seven barangays within the watersheds empty their water into the Laguna Lake through the natural river system and artificial drainage system which composes of canals and creeks. These barangays are Sucat, Buli, Cupang, Bayanan, Putatan, Poblacion and Tunasan.Table 23-1 shows the coordinates of the Sub-basin.
Table 23-1 Geographic extents CORNERS NORTHING (UTM) EASTING (UTM) Upper Left 1586911.50000 291383.06250 Upper Right 1586911.50000 284997.68750 Lower Right 1604487.25000 284997.68750 Lower Left 1604487.25000 291383.06250
Political Boundary The sub-basin is politically and administratively composed of six cities and municipalities such as Las Pinas, Muntinlupa, Paranaque, Taguig and Bacoor and Dasmarinas in Cavite. However, only the cities of Taguig and Muntinlupa are within the jurisdiction of LLDA. In addition, the sub- basin has a total of25 barangays (Table 23-2). Figure 23-2 illustrates the political map of the sub-basin which also shows the barangay distribution.
Table 23-2 Municipalities and Barangays Covered MUNICIPALITY/CITY NO. OF BARANGAYS AREA (HA) PERCENT (%) Bacoor 1 2.02 0.05 Dasmarinas 1 7.537 0.17 Las Pinas City 2 18.903 0.43 Muntinlupa City 9 3463.476 78.39 Paranaque City 5 213.011 4.82 Taguig City 7 713.367 16.15 TOTAL 25 4596.741
Since Muntinlupa and Taguig Cities cover the largest area percentage making up the sub-basin, the inhabitants residing within the sub-basin boundary were considered in this section. The Muntinlupa Sub-basin has a total population of 822,562 inhabitants based on 2007 NSO census. Table 21-3 shows the detailed population data of each cities as well as the annual growth rate.
Table 23-3 Population, 2007 CITY POPULATION ANNUAL GROWTH RATE (%) Muntinlupa City 415,348 1.10 Taguig City 152,109 1.28 TOTAL 567,457 0.98 National Statistics Office, 2007 Census of Population
Source: LLDA GIS Figure 23-2 Political Map
Land Cover
The Muntinlupa sub-basin is basically classified as urban, marshy, grass, water, and arable (Table 23-4). More than 50% of the sub-basin (84%) is still classified as arable as compared to the land classified as urban or highly built-up area such as residential, commercial and industrial to almost 40%. Figure 23-3 illustrates the Land Cover map of the sub-basin.
Table 23-4 Land Cover LAND COVER AREA (ha) PERCENTAGE (%) Arable 2372.220 54.11% Brush 18.962 0.43% Grass 251.586 5.74% Cloud 1.408 0.03% Marsh 33.337 0.76% Urban 1706.572 38.93% TOTAL 4540.858 100%
Source: LLDA GIS Figure 23-3 Land Cover Map
Sub-basin Characterization and Properties
Drainage Network / Properties The drainage map of the Muntinlupa Sub-basin is shown in Figure 23-4 while the important watershed characteristics and geomorphological features are in Table 23-5.
Table 23-5 Some Relief Features and Other Geo-Morphological Parameters PARAMETERS VALUES Area (ha) 4384.576 Perimeter (m) 42259.617 Total number of streams 31 Total length of streams (m) 48834.871 Stream Density (stream/ha) 0.00707 Drainage Density (m/ha) 11.1379 Constance of Channel Maintenance (ha/m) 0.0898 Length of Overland Flow (m) 5.5689 Source: LLDA GIS
Source: LLDA GIS Figure 23-4 Drainage Map
Sub-sub basin Properties
Source: LLDA GIS Figure 23-5 Sub-sub basin Map of Muntinlupa Sub-basin
Table 23-6 Muntinlupa Sub-sub basin properties SUB-SUB BASIN NAME AREA (Ha) PERIMETER (m) SSB-23A 264.410 6979.102 SSB-23B 277.829 6780.128 SSB-23C 698.051 15621.500 SSB-23D 523.336 13299.746 SSB-23E 513.265 17450.221 SSB-23F 680.414 17198.960 SSB-23G 618.777 13852.175 SSB-23H 502.828 16271.892 SSB-23I 305.047 6979.614 Source: LLDA GIS
Water Quantity
Streamflow
Table 23-7 shows the annual average stream flow of Muntinlupa River. The highest stream flow rate was recorded in 2003 with 3.22 m3/sec while the lowest was in 1997 with .55 m3/sec, which can be attributed to the El Nino phenomenon. The 15-year average flow rate is 1.71 m3/sec. Figure 23-6, shows the stream flow trend throughout the 14-year period.
Table 23-7 Streamflow Data, 1990-2004 YEAR STREAMFLOW 1990 2.404679922 1991 1.756803355 1992 1.878686684 1993 1.133528468 1994 0.728576965 1995 1.120443675 1996 1.11422885 1997 0.549416821 1998 0.861285902 1999 1.371702098 2000 2.91329774 2001 2.394972075 2002 2.507886971 2003 3.220691649 2004 1.740112005 Source: LLDA PDMED
Source: LLDA PDMED Figure 23-6 Streamflow for, 1990-2004
Water Balance The Sacramento Soil Mositure Accounting (SAC SMA) Hydrologic Model is used to simulate watershed rainfall-runoff relationship and to generate the long-term water balance of the 24 sub- basins of Laguna de Bay. The SAC SMA accounts for all water entering, stored in, and leaving a drainage basin. Though many parameters are used in this water balance accounting process, precipitation has the main impact on runoff.
The 15-year rainfall data simulation shows that on the average, 53.7% of total rainfall goes to direct run off, while 34% is lost to evapotranspiration. (Table 23-8 and Figure 23-7).
Table 23-8 Yearly Water Balances based on model simulation (mm) ACTUAL EVAPO- DIRECT CHANGE IN YEAR RAINFALL BASEFLOW TRANSPIRATION RUNOFF STORAGE 1990 2,208 685 1,298 373 (148) 1991 1,757 571 1,042 188 (44) 1992 1,991 605 1,120 192 74 1993 1,439 504 606 193 136 1994 1,011 668 312 182 (151) 1995 1,503 550 654 153 146 1996 1,470 705 601 180 (15) 1997 882 668 272 107 (164) 1998 1,339 567 493 66 214 1999 1,645 708 683 229 25 2000 2,865 750 1,845 296 (26) 2001 2,648 705 1,569 286 88 2002 2,724 751 1,655 288 29
ACTUAL EVAPO- DIRECT CHANGE IN YEAR RAINFALL BASEFLOW TRANSPIRATION RUNOFF STORAGE 2003 3,175 647 2,177 318 33 2004 2,049 670 1,090 262 27 AVERAGE 1,914 650 1,028 221 15 Source: LLDA PDMED
Source: LLDA PDMED Figure 23-7 Water Balances based on model simulation, 1990-2004