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Put basic profile here

The Pagsanjan-Lumban watershed is located in the Southern Tagalog Region, at the southeastern part of the Laguna de Bay basin. It is situated between north latitude 14° 37’ to 14° 21’ and east longitude 121° 24’ to 121° 37’. It is bounded by the Paete/Pangil/Pakil watershed in the east, Sta. Cruz watershed in the west, the east Bay of Laguna Lake to the north, and Mt. Banahaw to the south. Eight municipalities are located within the catchment, namely: Cavinti, Kalayaan, Luisiana, Lumban, Magdalena, Majayjay, and Pagsanjan in the Province of Laguna, and Lucban Municipality in Quezon Province.isque vulputate.

The watershed has an aggregate area of 45,445 hectare (ha), with a perimeter of 241 km and is composed of 4 major sub-watersheds, namely: Balanac (covering portions of Lucban, Luisiana, Magdalena, Majayjay, and Pagsanjan), Bombongan (covering part of Cavinti, Luisiana, Pagsanjan), Caliraya (covering part of Cavinti, Kalayaan, Lumban), and Lewin (covering part of Balubad and Lewin in Lumban). Balanac subwatershed covers the largest area of about 23,223 ha and perimeter length of 117 km. On the other hand, Lewin has the smallest area of about 882 ha.

The watershed has a relatively flat to moderately sloping to rolling topography starting from the lakeshore going towards the mountains. Greater percentage of each area, about 81.9 percent or 37,216 ha has a slope of 18 percent or less. The sloping to mountainous areas with more than 18 percent slope are approximately 8,229 ha or 18.1 percent of the total area. These could be found in the east, southeast (Sierra Madre Range) and south of the watershed going towards Mt. Banahaw.

Slope

Area (ha) per Subwatershed

Grand Total

Percentage (%)

Balanac

Bombongan

Caliraya

Lewin

0-3

5240.4

1102.7

1744.4

119.7

8207.2

18.1

3-8

6333.5

3826.6

3805.6

218.4

14184.0

31.2

8-18

6727.2

4617.4

3213.1

267.1

14824.8

32.6

18-30

2407.8

1457.2

878.1

132.4

4875.6

10.7

30-50

1740.1

488.7

90.8

103.8

2423.5

5.3

above 50

774.6

95.0

19.3

41.1

930.0

2.0

Grand Total

23223.6

11587.7

9751.3

882.6

45445.1

100

Elevation ranges from 20 to 2,080 meters above sea level (masl). The highest point in the watershed is located in Mt. Banahaw with an elevation of 2,080 masl. This is located within the Balanac subwatershed where most of the headwaters of the Balanac River emanate. Areas with the lowest elevation (20 masl) are found in the outlets of the Balanac, Bombongan and Lewin subwatersheds.

There are two climatic types in Pagsanjan-Lumban watershed. Climatic type 4 prevails in the towns of Cavinti, Kalayaan, Lumban, Majayjay, Magdalena and Pagsanjan, Laguna with rainfall more or less evenly distributed throughout the year. However, the third type of climate is experienced in some parts of Lumban and Magdalena. This is characterized by not very pronounced season, dry from November to April and wet during the rest of the year.

Climatic Type

 

Area (ha) per Subwatershed

Grand Total

Code

Balanac

Bombongan

Caliraya

Lewin

Season not very pronounced, dry form Nov to Apr and wet during the rest of the year

3rd Type

338.9

 

 

 

338.9

Rainfall more or less evenly distributed throughout the year

4th Type

22856.0

11587.7

9751.3

882.6

45077.5

Unknown

Unknown

28.7

 

 

 

28.7

Grand Total

 

23223.6

11587.7

9751.3

882.6

45445.1

Geomorphology

Morphometric parameters were grouped into three categories, namely: linear, areal and relief aspects. The parameters (i.e, area, perimeter, stream order, basin length, axial width and stream length) were extracted from the digital elevation model. Other parameters such as bifurcation ratio, stream length ratio, Rho coefficient, drainage density, stream frequency, drainage texture, length of overland flow, constant of channel maintenance, basin relief, relief ratio, relative relief, ruggedness number, gradient ratio, Melton ruggedness ratio, basin slope, Leminiscate ratio, form factor, circulatory ratio, elongation ratio and shape index were calculated using empirical equations presented in Table 6. The morphometric parameters for the delineated watersheds were calculated based on standard procedures (Horton (1945), Miller (1953), Schumm (1956), Strahler (1964), Nookaratnam et al. (2005), Yanina and Angillieri (2008), Sreedevi et al. (2009), Pankaj and Kumar (2009), and Vincy et al. (2012)).

Linear Aspects.

Stream Order The stream orders were determined based on Strahler’s method. Results of the anaylsis show that the watershed is a fourth order basin. The number of stream segments typically decreases significantly as the stream order increases. The watershed has a total of 52 stream segments with around 76% belonging to first order streams.

Stream Order

Number of Stream Segments (Sn)

Total Length of Streams (Sltotal) (km)

Log of Sn

Log of Sltotal

1

41

168.19

1.6128

2.2101

2

10

88.51

1.0000

1.9320

3

2

65.35

0.3010

1.8149

4

1

8.25

0.0000

0.9138

Stream Length The Pagsanjan-Lumban Watershed has a total stream length of 330.3 km and a perimeter of 162.57 km. Stream length is indicative of the contributing area of the watershed. Around 52 percent of this belongs to first order streams, 27% to second order streams, 20% to third order streams, and 1% to fourth order streams.

Relief Aspects

The relief of the watershed plays an important role in hydrologic flow and permeability.

Basin Relief

Basin relief is the vertical distance between the highest point of elevation and the lowest point of elevation in the watershed. This parameter affects stream gradients and may thus influence flooding patterns and sediment transport. The Pagsanjan-Lumban Watershed has a basin relief of 2.07km. Considering the distance from the farthest point to its mouth, the water would still travel far from its headwaters before it could reach the lowlands down to its mouth. In this case, flooding is gradual and flash floods would not normally occur at the downstream areas.

Relief Ratio

The relief ratio is the fraction of the elevation between the highest and lowest points in the watershed, and the length of the longest dimension of the watershed parallel to its principal drainage line. Relief ratio is associated with precipitation since precipitation generally increases with increasing elevation due to orographic effect and the values also typically increases as the drainage area and sub-watershed size of a given drainage basin decreases. High relief ratios usually indicate steep slopes and high relief in the watershed area. The watershed has a relief ratio of 0.08, which is moderately low implying that the gradient of flow of the streams are not so steep and hence the time of concentration of the runoff in the watershed outlet is likely to be long and not prone to flashfloods.

Ruggedness Number

Ruggedness number is the bifurcation ratio of a catchment over the length of streams per unit area in the said watershed. It also indicates the terrain complexity of a given catchment. Watersheds with high ruggedness numbers are generally more susceptible to erosion than those with lower values. The ruggedness ration of the Pagsanjan-Lumban Watershed is 2.86.

Melton’s Ruggedness Number

Melton’s ruggedness number is the difference between maximum and minimum elevation in the watershed divided by the square root of the size of the watershed area. The watershed has a 0.1 Melton’s ruggedness number.

Rotundity Ratio

The rotundity ratio of a watershed is the ratio of the area of a circle with a diameter equal to the distance of the outlet to the remotest part of the watershed, and the watershed area. The rotundity ratio of the watershed is 0.01.

Relief Aspects

Values

Max elevation (H), m asl

2074

Min elevation (h), m asl

2

Basin relief (Rb), km

2.07

Relief ratio (Rr)

0.08

Mean slope (Sm), deg

6.38

Ruggedness number (Rn)

2.86

Melton’s Ruggedness number (MRn)

0.10

Rotundity ratio (Ror)

0.01

Areal Aspects

The Pagsanjan-Lumban Watershed has an approximate area of 454.45km2.

Drainage Density

Drainage density of 0.72 km/km2. Drainage density basically measures how well a catchment is drained by its network of stream channels. It is the total length of all perennial and intermittent streams per unit area of watershed. Normally, the size of individual drainage units decreases as the drainage density increases proportionally. In the case of the Pagsanjan-Lumban Watershed, the drainage density value is relatively high, which may be due to the presence of impermeable sub-surface material, sparse vegetation and high relief. Low drainage density leads to a coarse drainage texture while high drainage density leads to fine drainage texture.

Constant of Channel Maintenance

The constant of channel maintenance is an indicator of the minimum runoff area required to generate and sustain a permanent channel of the first order. It is the total area of the watershed divided by the the total length of all the streams and rivers in the watershed. The constant channel of maintenance of the Pagsanjan-Lumban Watershed is 1.37 km2/km. In other words, a one kilometer long perrenial stream of the first order requires 1.37 km2 or 720,000m2 of runoff area to sustain it. This indicates that the watershed less affected by either structural disturbance, low permeability, steep to very steep slopes or high surface runoff.

Elongation Ratio

Elongation ratio is the ratio between the diameter of a circle with the same area as the watershed and the maximum length of the watershed which is the distance from the outlet to the farthest point in the watershed. The elongation ratio of the Pagsanjan-Lumban watershed is around 0.89, which shows that the watershed are is more circular rather than elongated. Circular watersheds typically have quick but lower hydrographic peak compared to the oval and elongated watersheds

Compactness Constant

The compactness constant expresses the relationship of the watershed with that of a circular watershed having the same area. A circular watershed yields the shortest time of concentration before peak flow occurs. A compactness constant equal to one indicates that the basin completely behaves as a circular basin, while a compactness constant greater than one indicates more deviation from the circular nature of the basin. The compactness constant of the watershed is 1.37. This means that the watershed deviates from a circular watershed

Stream Frequency

Stream frequency is the total number of streams of any order per unit area. The stream frequency of the watershed is 0.12/km2, which is quite low. This indicates high surface permeability and infiltration capacity in the watershed which is indicative of a good amount of vegetation cover in the area. This also reflects longer or later peak discharge which makes flash floods less likely due to low runoff rates as indicated by the lesser number of streams.

Drainage Texture

The drainage texture is an expression of the relative channel spacing in a fluvial dissected terrain. It depends upon a number of factors such as climate, rainfall, vegetation, rock and soil type, infiltration capacity, and relief. The watershed has a very coarse drainage texture of 0.9/km. Hydrologically, very coarse texture watersheds have large basin lag time periods. This indicates that the Pagsanjan-Lumban Watershed exhibits a longer duration to peak flow.

Texture Ratio

Texture ratio is one of the most important factors in the drainage morphometric analysis, which depends on the underlying lithology infiltration capacity, and relief aspect of the terrain. It is expressed as the ratio between the first order streams and perimeter of the watershed. The texture ratio of the watershed is 0.25 streams/km. This is also quite low and has a hydrologically long basin lag time. This confirms the results of previous morphometric characteristics.

Shape Index

Rate of water and sediment yield along the length and relief of the drainage basin is largely affected by the shape. Shape index is equal to the square of the length of the watershed divided by the area of the watershed. The watershed shape index is 3.22/2.13 which indicates a relatively shorter basin lag time.

Shape Factor

The shape factor of the watershed of 1.58 and is the reciprocal of its 0.68 form factor. These parameters are similar in interpretation to circularity ratio and elongation ratio. It gives an idea about the circular character of the basin. The values of form factors are less than one whereas the values of shape factors are greater than one. The closer they are to one, the more circular they are. The greater the circular character of the basin is, the greater is the rapid response of the watershed after a storm event.

Length of Overland Flow

Length of overland flow is the length of water over the ground before it gets concentrated into definite stream channel. This factor basically relates inversely to the average slope of the channel and is quite synonymous with the length of sheet flow to a large degree. The length of overland flow approximately equals half of the constant of channel maintenance. The watershed has a 0.68km length of overland flow. This means that runoff flows an average distance of 680m before it enters a permanent water channel in the watershed.

Geometric Similarity Constant

The geometric similarity constant is defined as the ratio of the area of the watershed to the square of the maximum length of stream. The watershed has a geometric similarity constant of 0.31.

Lemniscate Ratio

The lemniscate ratio is the ratio between the lemniscate perimeter, corresponding to the length and area of the watershed analyzed, and the actual perimeter of the watershed. Leminiscate ratio of the Pagsanjan-Lumban watershed is 0.8.

Characteristics

Values

Area (A), km2

454.45

Drainage density (Dd), km/km2

0.72

Constant Channel of maintenance (CCm), km2/km

1.37

Circulatory ratio (Rc)

0.21

Elongation ratio (Re)

0.89

Compactness constant (Cc), km

2.15

Stream frequency (Fs), stream/km2

0.12

Drainage texture (Rt), /km

0.90

Texture ratio (Tr), stream/km

0.25

Shape index (Si)

1.59

Form factor (Ff)

0.63

Shape factor (Sf)

1.58

Length of overland flow (Lof), km

0.68

Geometric similarity constant (Gsc)

0.31

Leminiscate ratio (RL)

0.80

Soils

The Pagsanjan-Lumban watershed is underlain by three age-rock formations namely, the Oligocene-Miocene, the Pliocene-Quaternary, and recent rock formation (Figure 18). The Oligocene-Miocene association is a mixture of rocks formed 5.3 to 40 million years ago. The Pliocene-Quaternary association is a mixture of rocks formed recently, in terms of geologic time scale, to 5.3 million years ago. The areas classified under “recent” are relatively fresh sediment deposits. Table 12 shows the area of geology per subwatershed.

Soil Series

Subwatershed

Grand Total

Balanac

Bombongan

Caliraya

Lewin

Antipolo sandy clay

 

654.6

 

 

654.6

Bay clay

65.5

 

 

96.1

161.6

Hydrosol

1483.0

 

 

22.1

1505.1

Lake

 

439.9

513.5

27.3

980.6

Lipa loam

2618.1

15.9

 

 

2634.0

Luisiana clay loam

11323.8

5667.5

3154.5

243.3

20389.1

Luisiana sandy clay loam

3677.6

 

 

 

3677.6

Macolod clay loam

94.7

 

 

 

94.7

Marikina silt loam

685.7

 

 

0.8

686.5

Marikina silty clay loam

457.8

 

 

 

457.8

Mountain soil (undifferentiated)

2353.4

4505.9

4583.0

 

11442.3

Paete clay loam

463.9

303.9

1500.4

493.1

2761.3

Grand Total

23223.6

11587.7

9751.3

882.6

45445.1

 

Vegetation Characteristics

The analysis of the diversity of the area was done plot by plot. This is for the analysis of the different vegetation in the area, namely, trees, saplings, and undergrowth vegetation. For the monitoring plot in Cavinti, Laguna, the 20m x 20m subquadrat which contains the trees measuring > 5cm at dbh has a species richness of 72 species belonging to 39 families.

The total of 130 species identified in the 10m x 10m plots (trees measuring < 5 cm at dbh) belonging to 47 families while 15 species of undergrowth plants including bamboo, pandan, and herb were identified in the 1m x 1m subquadrat which belong to 12 families. Table 18 shows the comparison of the three plots with their corresponding species richness.

For the monitoring plot in Cavinti, Laguna, the 20m x 20m subquadrat which contains the trees measuring > 5cm at dbh has a species richness of 72 species belonging to 39 families.

The 10m x 10m subquadrat has larger species richness than the 20m x 20m subquadrat, which means that the tree saplings identified in the 10m x 10m plots may, in 10 years or more, contribute to the number of tree species in the 20m x 20m subquadrat if they are not weeded out by the residents or the owner of the land. The low number of species identified in the 1m x 1m plot is mainly due to the little regeneration in some of the plots. All subquadrats have plant species except subquadrats 11, 15, 23, 27, 37, 38, 40, 42, 45, 46, and 50 with no plant species inside.

Based on the number of individuals, it was observed that Cocos nucifera, Lansium domesticum, and Sandoricum koetjape are the most dominant or visible in the 20m x 20m subquadrat consistent with the current use of the area for cultivation of tree crops. The dominance of coconuts and other horticultural crops in the area notwisthstanding, there are stil many tree species in the 20m x 20m subquadrat that are indicative of the original vegetation in the area.

In the 10m x 10m subquadrat, Ficus nota, Lansium domesticum, and Ptychosperma macarthurii are the most dominant in terms of the number of individuals. Even in the sapling stage, Lansium domesticum are still dominant. This may be attributed to the preparation and possible expansion of the area for planting more lanzones. Also, because of the presence of many Lansium domesticum trees and through consumption of people and animals of its fruits, the dispersion of its seeds in the whole area are faster than other less dominant species.

Donax cannaeformis, Pandanus simplex, and Solanum torvum are the most dominant species in the 1m x 1m subquadrat in terms of number of individuals. The presence of Donax cannaeformis indicates that the area, even though it is cultivated, is not frequently disturbed by humans allowing greater chance for other species to thrive even though they are not the species of interest by the community.

To further analyse the vegetation in the area, the Importance value of each of the species in every plot were computed. Importance value is based on the average number of individuals of a species per square meter (relative density), the amount of forest area occupied by the species (relative dominance), and the frequency of occurrence of a species (relative frequency). The species with the highest IV is the most important species in the BMP.

Cocos nucifera has the highest importance value with 54.39%, followed by Sandoricum koetjape (40.11%) and Lansium domesticum (32.51%). Again, this is due to the current land use of the area which is mainly for cultivation of fruit trees. Some trees got some fair IVs compared to the ones with the highest. Artocarpus heterophyllus, Fragrea racemosa, and Ficus nota got an IV of 13.48%, 12.30%, and 11.22% respectively. Unfortunately, there are some species like Actinodaphne apoensis (0.45%) that were found in the BMP with only has 1 individual resulting to low IV. There is a chance that these species can be wiped out if nothing is done to propagate and protect them.

Table of 10 highest IV in 20m x 20m plot

SPECIES

DENSITY

DOMINANCE

FREQUENCY

RDEN

RDOM

RF

IV

Cocos nucifera

0.0072

0.00050129

0.68

18.653

24.879

10.863

54.395

Sandoricum koetjape

0.00355

0.000461896

0.5

9.1969

22.924

7.9872

40.108

Lansium domesticum

0.0065

0.000193401

0.38

16.839

9.5985

6.0703

32.508

Artocarpus heterophyllus

0.0016

4.64925E-05

0.44

4.1451

2.3074

7.0288

13.481

Fragrea racemosa

0.00195

3.65099E-05

0.34

5.0518

1.812

5.4313

12.295

Ficus nota

0.00195

2.76763E-05

0.3

5.0518

1.3736

4.7923

11.218

Cyathea contaminans

0.00235

1.31783E-05

0.22

6.0881

0.654

3.5144

10.257

Endospermum peltatum

0.00185

5.84625E-05

0.16

4.7927

2.9015

2.5559

10.25

Dracontomelon edule

0.00125

3.16691E-05

0.28

3.2383

1.5717

4.4728

9.2829

Arenga pinnata

0.0008

7.04999E-05

0.16

2.0725

3.4989

2.5559

8.1274

The IV of the 10m x 10m plot was also computed. Graptophyllum pictum with a value of 26.49% has the highest IV followed by Ficus nota with 20.98% and Lansium domesticum with 20.69%. Only one (Lansium domesticum) from the three most important species in the 20m x 20m subquadrat is also dominant in the 10m x 10m subquadrat. This means that even though fruit trees are dominating in the area, other species too have the capacity to reproduce themselves therefore giving their species a great chance to prosper in the area.

Table of 10 most dominant species in 10m x 10m plot

SPECIES

DENSITY

DOMINANCE

FREQUENCY

RDEN

RDOM

RF

IV

Clerodendrum quadriloculare

0.00615

1.07655E-06

0.38

13.00211416

9.012765327

4.470588235

26.48546773

Ficus nota

0.00385

9.42951E-07

0.42

8.139534884

7.894306596

4.941176471

20.97501795

Lansium domesticum

0.00305

1.1953E-06

0.36

6.44820296

10.00695087

4.235294118

20.69044794

Artocarpus blancoi

0.00185

6.82513E-07

0.4

3.911205074

5.713936725

4.705882353

14.33102415

Diospyros blancoi

0.0019

8.34173E-07

0.18

4.016913319

6.983627383

2.117647059

13.11818776

Planchonia spectabilis

0.00175

4.23723E-07

0.32

3.699788584

3.547374986

3.764705882

11.01186945

Ptychosperma macarthurii

0.00205

6.64056E-07

0.04

4.334038055

5.559417147

0.470588235

10.36404344

Melicope triphylla

0.0014

3.85003E-07

0.32

2.959830867

3.223212638

3.764705882

9.947749387

Pterocarpus indicus

0.0013

3.81508E-07

0.3

2.748414376

3.193952548

3.529411765

9.471778689

Artocarpus ovatus

0.0019

1.26921E-07

0.34

4.016913319

1.062568671

4

9.07948199

Donax cannaeformis has the highest IV in the 1m x 1m subquadrat with a value of 67.3%, 19 points higher than the second one which is Pandanus simplex (48.58%). Undergrowth vegetation has an IV of 1.7-5.67.

Table of 10 most dominant species in 1m x 1m plot

Species

Family

DENSITY

FREQUENCY

RDEN

RDOM

IV

Donax cannaeformis

Marantaceae

0.00675

0.4

39.13043478

28.16901

67.29945

Pandanus simplex

Pandanaceae

0.00425

0.34

24.63768116

23.94366

48.58134

Solanum torvum

Solanaceae

0.0023

0.22

13.33333333

15.49296

28.82629

Bambusa vulgaris

Poaceae

0.0014

0.08

8.115942029

5.633803

13.74974

Nephrolepis biserrata

Lomariopsidaceae

0.0009

0.08

5.217391304

5.633803

10.85119

Lygodium flexuosum

Selaginelaceae

0.00025

0.06

1.449275362

4.225352

5.674627

Xanthosoma violaceum

Araceae

0.0003

0.04

1.739130435

2.816901

4.556032

Selaginella plana

Lygodiaceae

0.0005

0.02

2.898550725

1.408451

4.307001

Alocasia zebrine

Araceae

0.0001

0.04

0.579710145

2.816901

3.396612

Musa ornate

Araceae

0.0001

0.04

0.579710145

2.816901

3.396612

Data on the vertebrate faunal diversity of Bombongan-Lewin Watershed are undeniably wanting. Since this watershed is part of the Mt. Banahaw Landscape, related documents on its biodiversity that serve as secondary data are those literatures on the previous biodiversity studies conducted in Mt. Banahaw-San Cristobal National Park, currently known as Mt. Banahaw-San Cristobal Protected Landscape (MBSCPL). Early wildlife vertebrate surveys and inventories were conducted in Lucban and Tayabas portions of MBSCPL. Data from the studies show a total of 226 species of birds, 62 mammals, 38 reptiles and 43 amphibians. Notably, a number of endemic, threatened and rare species was recorded from the area. Some of the endemic wildlife vertebrate fauna found in MBSCPL include the following:

Birds – Phil. falconet (Microhierax erythrogonys), Scale-feathered malkoha (Lepidogrammus cumingi; =Phaenicophaeus cumingii), Guaiabero (Bolbopsittacus lanulatus), Phil. hanging parakeet (Loriculus philippinensis), Crimson-backed woodpecker (Chrysocolaptes lucidus) and White-browed shama (Copsychus luzoniensis);

Mammals – Luzon montane forest mouse (Apomys sp.), Luzon Cordillera forest mouse (Apomys spp.), Large Luzon forest rat (Bullinus luzonicus), Nothern Luzon shrew rat (Rhynchomys sp.), Luzon pygmy fruit bat (Otopteropus cartilagonodus), and Long-nosed Luzon forest mouse (Apomys sp.);

Reptiles – Slender tree skink (Lipinia auriculatum), Two-striped mabouya (Mabuya multicarinata), Common ground mabouya (Mabuya multifasciata), Beyer’s sphenomorphus (Sphenomorphus beyeri), Steere’s sphenomorphus (Sphenomorphus steerei), Philippine pit viper (Trimeresurus flavomaculatus), Philippine sailfin lizard (Hydrosaurus postulosus), Cox’s sphenomorphus (Sphenomorphus coxi), Black-sided sphenomorphus (Sphenomorphus decipiens), Jagor’s sphenomorphus (Sphenomorphus jagori jagori), and Banded krait (Calliophis calligaster calligaster);

Amphibians – Corrugated forest ground frog (Platymantis corrugatus), Common forest ground frog (Platymantis dorsalis Dumerii), Philippine woodland frog (Rana magna macrocephala), Woodworth’s frog (Rana woodworthi), Smooth-skinned tree frog (Philautus surdus ) and Slender-digit narrow mouth frog (Kaloula picta), and the recently described Banahao forest frog (Platymantis banahao).

 

Administration

The Pagsanjan-Lumban Watershed is found in the provinces of Laguna and Quezon. It is situated within the administrative boundaries of 9 Municipalities and the City of Tayabas. Of these, seven (7) are in Laguna while two (2) are from Quezon including Tayabas City. The seven municipalities in Laguna are namely, Cavinti, Liliw, Luisiana, Lumban, Magdalena, Majayjay, and Pagsanjan. The two others in Quezon are Lucban and Sampaloc. Among these, Cavinti, Lumban, Majayjay, and Pagsanjan have all their respective barangays within the watershed. In contrast, the City of Tayabas only has a single barangay in the watershed. Majayjay has 40 barangays – the most number of barangays within the watershed.

Three municipalities cover areas larger than 15 percent of the watershed area specifically, Cavinti, Lucban, and Majayjay. Collectively, the three comprise 59.17 percent of the entire watershed area. Conversely, both Liliw and Tayabas have land areas with less than half a percent of the Pagsanjan- Lumban Watershed area. Together, the two comprises only 0.45 percent of the watershed area with the Liliw contributing only roughly 13 percent of this.

City/Municipality

Total Number of Barangays

Barangays per Municipality Within the Watershed

Percent of Watershed Area

Number

Percentage

CAVINTI

19

19

100

23.39

CITY OF TAYABAS

29

1

3.44

0.39

LILIW

33

7

21.21

0.06

LUCBAN

32

30

93.75

18.04

LUISIANA

23

15

65.22

11.07

LUMBAN

16

16

100

12.14

MAGDALENA

24

19

79.17

4.92

MAJAYJAY

40

40

100

17.74

PAGSANJAN

16

16

100

10.11

SAMPALOC

14

3

21.43

2.14

Demography

Demography refers to the study of size, structure, composition, distribution, density, growth, and movement of human population. It is an important basis for determining interventions that would address the needs for livelihood, food, education, health, housing, water, electricity, and other social services.

Specifically, demographics looks at how the number of households, family size, growth rate, density, population structure, dependency, ethnicity, and migration affect the structure and composition of the community and the household. These in turn affect the affect the socio-political dynamics of at the community and the watershed levels, and their ability to cope with economic stress.

Total Population

As of the last census year in 2010, the 166 barangays of the Pagsanjan-Lumban Watershed had a total population of 209,006 with around 43,543 households based on the average 4.8 members per household. Of the municipalities, Lucban has the highest population with 45,931 people and accounts for 21.98 percent of the total, while Sampaloc has the lowest population and accounts for 0.16 percent of the entire watershed population. At the barangay level, Barangay Ayuti in Lucban, is the most populated, with a population of 7,991. Conversely, Barangay Taquico of Sampaloc, Quezon has the least population of only 24 people.

City/Municipality

Province

Watershed Population

Cavinti

Laguna

20,859

City of Tayabas

Quezon

4,371

Liliw

Laguna

6,660

Lucban

Quezon

45,931

Luisiana

Laguna

14,132

Lumban

Laguna

29,470

Magdalena

Laguna

21,382

Majayjay

Laguna

26,547

Pagsanjan

Laguna

39,310

Sampaloc

Quezon

344

Gender

In terms of gender, there are slightly more females in the watershed population than there are males. Females make up around fifty-one percent (51%) of the entire watershed population, while males make up the remaining forty-nine percent (49%).

Age Structure

The age structure of a population is the distribution of people among various ages. Looking at the population structure of the watershed in a population pyramid reflects the temporal changes in population growth rate. It is evident that the age distribution of the watershed population has started to shift from an expansive age structure where the population pyramid had a very wide base tapering to a very narrow peak, to a more stable age structure where tapering is less. This indicates that the population growth rate is decreasing, which is evident with the tapering base, and the average life expectancy of individuals is increasing. Furthermore, it can be surmised that a higher percentage of females live past the age of sixty-four (64) compared to their male counterparts.

Education

The literacy rate of people living in the watershed who are at least 10 years of age is 98.65%, which is higher than the 97.5% literacy rate for the entire Philippines for the 2010 NSO census. However, this is only slightly lower than the regional average literacy rate of CALABARZON or Region IV-A during the same time period which is a 99.3% literacy rate.

Approximately 28.29% of the total number of households are engaged in farming. However, unlike the national statistics, the percentage of the population in the watershed employed in agriculture is only around 14.05% or roughly one-third of the national value. Nevertheless, this does not take into account those family members that help in farming activities but are not engaged in them on a full-time basis or those indirectly employed by agriculture.

Agriculture in the watershed is generally faced with three major problems. These are namely: lack of irrigation, inadequate farm-to-market roads, and inactive farmers’ cooperatives.

Farm Tenure

Within the Pagsanjan-Lumban watershed, most of the farmlands are privately owned by the farmers themselves. In other words, most of the farmers in the watershed have freehold over the land they are utilizing. Farmlands that are owned by their respective farmers make up around 49% of the farm lots in the area. The second most common tenure status of farmlands in the watershed is the tenanted farmlands. These are farmlands that being farmed by tenants rather than the actual landowner. Tenants are farmers that cultivate a farmland owned by another individual usually by entering into income or harvest sharing agreements with the land owner, however periodic payments may also be included in the agreements. Tenanted farmlands comprises around 38% of farmland in the watershed. Less common is the leasing of farmlands. Leasing comprises around only 10% of the tenure status of farmlands in the watershed. Lessees typically that cultivate a farmland owned by another individual usually by entering a lease agreement with the lessor. The lessee typically enters into periodic payments with the lessor in exchange for the use of their land. The least common tenure status of farmlands in the watershed are the tax declared and the CLC/T, which together comprises only 3% of the current tenure status of farmlands.

Farm Types

Farm Size

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Land Cover Agricultural Barren Forest Pasture Range Urban Water
Area (ha) 28165.08 52.64 2867.93 1.06 5957.80 1231.22 1998.06
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