TABLE OF CONTENTS

Volume 12. Caliraya Sub-basin ...... 3 Geographic Location ...... 3 Political and Administrative Boundary ...... 4 Land Cover ...... 5 Sub-basin Characterization and Properties...... 8 Drainage Network ...... 8 Sub-sub basin Properties ...... 10 Water Quantity ...... 11 Streamflow ...... 11 Water Balance ...... 12

LIST OF FIGURES Figure 12-1 Geographical Map ...... 3 Figure 12-2 Political Map ...... 5 Figure 12-3 Land Cover Map ...... 7 Figure 12-4 Drainage Map ...... 9 Figure 12-5 Sub-sub basin Map of Caliraya Sub-basin ...... 10 Figure 12-6 Streamflow, 1990-2004 ...... 12 Figure 12-7 Water Balances based on model simulation, 1990-2004 ...... 13

LIST OF TABLES Table 12-1 Geographic Extent ...... 4 Table 12-2 Municipalities and Barangays Covered ...... 4 Table 12-3 Population Distribution by Municipality, 2007 ...... 5 Table 12-4 Area Distribution of Land Cover ...... 6 Table 12-5 Some Relief Features and Other Geo-Morphological Parameters ...... 8 Table 12-6 Caliraya Sub-sub basin properties ...... 11 Table 12-7 Streamflow Data, 1990-2004...... 11 Table 12-8 Yearly Water Balances based on model simulation (mm)...... 12

Technical writer For. Azyleah C. Abino, LLDA-PDMED

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, LLDA-PDMED

Volume 12. Caliraya Sub-basin

Geographic Location The Caliraya sub-basin is located at the southeastern part of the de Bay basin and about 105 km southeast of Metro . It is approximately situated between 121029’59.15” to 121036’58.75” longitude and 14o22’4.16” to 14o12’58.54” latitude. It is bounded by the // sub-basin in the east, sub-basin in the west, the East Bay of Laguna Lake to the north, and Mt. Banahaw to the south. Six municipalities coming from two provinces are located within the sub-basin, namely , Kalayaan, and Paete in the Province of Laguna and and Sampaloc in Province. Figure 12-1 illustrates the geographic location and boundary of the Caliraya sub-basin in the .

Source: LLDA GIS Figure 12-1 Geographical Map

The whole sub-basin has an aggregate area of 13,526.21 hectares, with a basin length of 3.55 kilometers (km) bounded with 45.5 52.84 km perimeter length. The geographic extent of the sub-basin is presented in Table 12-1.

Table 12-1 Geographic Extent CORNERS NORTHING (UTM) EASTING (UTM) Upper Left 1571566.12500 351784.40727 Upper Right 1571566.12500 336096.34375 Lower Right 1590120.87500 336096.34375 Lower Left 1590120.87500 351784.40727 Source: LLDA GIS

Political and Administrative Boundary The Caliraya sub-basin covers 21 barangays located in six municipalities in the Province of Laguna and Quezon (Figure 12-2). Table 12-2 shows the name of barangays making up the sub-basin. Cavinti has the most with eight followed by Paete with five. Mauban in the Province of Quezon has the least number of with only one.

On the other hand, in terms of area covered, Lumban dominates the area with 5,056.89 hectares or 37.39%, followed by Kalayaan having an area of 3,701.08 hectares or 27.36% and Cavinti with 3,428.95 hectares or 25.35% of the sub-basin. Only 11.20 hectares or 0.08% of the sub-basin is attributed to Mauban, Quezon (Table 12-2).

Out of the 13,526.21 hectares total land area of the sub-basin, of which 6,126.32 hectares are found within the reserve. As such, the National Power Corporation by virtue of Presidential Proclamation No. 573 has jurisdiction, authority and control over watershed reservation areas supporting power generating plants and properties including Caliraya and Lumot River Forest Reserve while the Department of Environment and Natural Resources (DENR) through the Laguna Lake Development Authority (LLDA) manages the areas fall outside of it.

Table 12-2 Municipalities and Barangays Covered MUNICIPALITY NO. OF BARANGAYS AREA (ha) PERCENTAGE Cavinti, Laguna 8 3,428.95 25.35 Kalayaan, Laguna 3 3,701.08 27.36 Lumban, Laguna 2 5,056.89 37.39 Paete, Laguna 5 1,246.43 9.21 Mauban, Quezon 1 11.20 0.08 Sampaloc, Quezon 2 81.68 0.60 TOTAL 21 13,526.21 100.00

The 2007 Census of Population by the National Statistics Office indicated that the total population within the Caliraya sub-basin is estimated at 46,300. Kalayan which ranks second largest municipality within the sub-basin, shared the highest number of inhabitants with 38% or 17,408. Next is by the municipality of Lumban with 25% or 11,434 residents followed closely by Paete having 24% or 11,113. Cavinti has the most number of barangays (8) within the sub- basin, however, it contributes the least number of inhabitants with only 14% or 6,345. Table 12- 3 shows the detailed population data of each municipalities as well as the annual growth rate.

Table 12-3 Population Distribution by Municipality, 2007 MUNICIPALITY POPULATION ANNUAL GROWTH RATE (%) Cavinti, Laguna 6,345 0.68 Kalayaan, Laguna 17,408 1.10 Lumban, Laguna 11,434 1.28 Paete, Laguna 11,113 0.98 Total 46,300 National Statistics Office, 2007 Census of Population

Source: LLDA GIS Figure 12-2 Political Map

Land Cover Based on most recent data, the land covers in Caliraya sub-basin were classified into forest, arable land, plantation, grassland, brushland, urban/built up areas. Some 38% or 5,685 hectares of the total area of the sub-basin is unclassified while 10% or 1,534 hectares is identified as municipal water comprising the man-made lakes: Caliraya and Lumot. Table 12-4 show the land cover distribution in the sub-basin of Caliraya while Figure 12-3 shows the land cover map.

The Caliraya-Lumot sub-basin area is dominated by non-forest areas including a mix of seasonal slash and burn brushland and grasslands (18% or 2,738 hectares). The more inaccessible areas contain secondary and degraded forest which accounts to only 4% or 579 hectares. The secondary forests were mostly found in the northeastern part of the sub-basin and a small patch was located in Holon in Barangay Paowin. There are 200 known tree species in the area, seven of which belong to the family Dipterocarpaceae. The non-dipterocarpaceae species commonly found in the area include Dillinea philippinensis, Litsea peroteti, Sandoricum koetjape, Canarium asperum, Macaranga bicoor, among others. Coconut plantations intercropped with other perennials, mainly fruit trees like Sandoricum koetjape, Artocarpus heterophyllus and Mangifera indica are also found within spreading approximately 15% or 2,299 hectares. Areas where land use is considered as agriculture or arable (4% or 606 hectares) include mainly annuals. Rice, cassava and sweet potato are the major crops raised.

Around the Caliraya and Lumot lakeshore there are built up areas (11% or 1,639 hectares) with some patches of coconut groves and agricultural crops. These areas are mainly residential in nature with few small commercial establishments. The areas devoted to real property development are those with big recreational resort developments. They are concentrated around the Caliraya Lake.

Table 12-4 Area Distribution of Land Cover LAND COVER AREA (ha) PERCENTAGE Urban 1,639.01 10.87% Forest 579.24 3.84% Arable 605.64 4.02% Plantation 2,298.72 15.24% Grassland 464.25 3.08% Brushland 2,274.11 15.08% Marsh 0.08 0.00% Unclassified 5,684.93 37.70% Water (lake) 1,533.69 10.17% TOTAL 15,079.67 100.00%

Source: LLDA GIS Figure 12-3 Land Cover Map

Sub-basin Characterization and Properties

Drainage Network The drainage map of the Caliraya Sub-basin is shown in Figure 12-4 while the important watershed characteristics and geomorphological features are in Table 12-5.

Table 12-5 Some Relief Features and Other Geo-Morphological Parameters PARAMETERS VALUES

Area (ha) 13,521.856 Perimeter (m) 80,569.559

Total number of streams 67

Total length of streams (m) 98,155.140

Stream Density (stream/ha) 0.00495 Drainage Density (m/ha) 7.2590

Constance of Channel Maintenance (ha/m) 0.1378

Length of Overland Flow (m) 3.6295

Source: LLDA GIS

Five tributary rivers and streams directly empty into the Caliraya Lake. The largest of these is the Cayabatoc River in the northeastern region. Cayabatoc River is fed by the BayRiver from the northeast and by the Nalba River in the northwest. Based on the hydrologic records of the reservoir, the average inflow from its 12 tributary rivers and streams is around 40 cm.

Source: LLDA GIS Figure 12-4 Drainage Map

Sub-sub basin Properties

Source: LLDA GIS Figure 12-5 Sub-sub basin Map of Caliraya Sub-basin

Table 12-6 Caliraya Sub-sub basin properties SUB-SUB BASIN NAME AREA (Ha) PERIMETER (m) SSB-12A 264.483 12470.289 SSB-12B 660.092 14108.126 SSB-12C 1820.046 26059.541 SSB-12D 1033.645 18245.321 SSB-12E 471.869 9819.553 SSB-12F 715.096 12755.246 SSB-12G 925.132 15308.054 SSB-12H 428.076 9223.141 SSB-12I 1005.592 15619.226 SSB-12J 510.649 10955.012 SSB-12K 256.335 8195.594 SSB-12L 182.609 7647.116 SSB-12M 614.313 15256.783 SSB-12N 4633.852 54511.154 Source: LLDA GIS

Water Quantity

Streamflow

The calculated 15-year discharge data of the Caliraya sub-basin is illustrated in Table 12-7 and Figure 12-6 wherein the maximum and minimum streamflow were recorded in the Year 2004 and 1997 with an average velocity of 18.63 m3/sec and 5.85 m3/sec, respectively. Generally, the yearly average streamflow of the sub-basin is fluctuating throughout the recoding period.

Table 12-7 Streamflow Data, 1990-2004. YEAR STREAMFLOW 1990 11.24824 1991 7.92831 1992 8.149183 1993 9.459903 1994 7.66526 1995 11.8512 1996 10.98735 1997 5.850447 1998 14.49947 1999 15.09205 2000 8.489402 2001 6.588049 2002 7.503556 2003 6.021479 2004 18.63081 Source: LLDA PDMED

Source: LLDA PDMED Figure 12-6 Streamflow, 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.

For Caliraya River Basin, the long term water balances of the basin based on the hydrologic simulation is shown in the table belowError! Reference source not found.. The 15-year average would show that 58.15% of the total rainfall becomes surface run-off, and about 25.71% of rainfall is lost as actual evapotranspiration. The base flow component of the total run- off is quite minimal, with only about 13.04% of rainfall, while the remaining 3.11% is stored as soil moisture and contributes to groundwater aquifer (Figure 12-7).

Table 12-8 Yearly Water Balances based on model simulation (mm). ACTUAL EVAPO- DIRECT CHANGE IN YEAR RAINFALL BASEFLOW TRANSPIRATION RUNOFF STORAGE 1990 3,451 800 2,116 473 61 1991 2,752 870 1,390 411 80 1992 2,824 887 1,498 373 66 1993 3,149 769 1,835 365 180 1994 2,645 887 1,317 429 12 1995 3,739 778 2,307 460 194 1996 3,523 890 2,049 487 98 1997 2,234 887 923 396 28 1998 4,441 919 2,836 460 227 1999 4,397 800 2,885 568 144 2000 2,792 811 1,512 429 39 ACTUAL EVAPO- DIRECT CHANGE IN YEAR RAINFALL BASEFLOW TRANSPIRATION RUNOFF STORAGE 2001 2,443 847 1,156 371 68 2002 2,681 826 1,357 382 116 2003 2,166 759 1,078 318 11 2004 5,249 735 3,931 400 183 AVERAGE 3,232 831 1,879 421 100

Source: LLDA PDMED Figure 12-7 Water Balances based on model simulation, 1990-2004