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Philippines is endowed with rich water resources. It has varying sources coming from 421 principal rivers, 59 natural lakes, numerous individual streams and four major groundwater reservoirs. When aggregated, this accounts for about 50,000 square kilometers (NSCB, 2013). Overall, the Philippines’ total available freshwater resource is at 145,900 MCM/year based on 80% probability for surface water, and groundwater recharge or extraction at 20,000 MCM/year (NWRB-SPM, 2003). With this, groundwater contributes to 14% of the total water resource potential of the country (Greenpeace, 2007).

However, even with an abundant source of water, there is growing alarm on issues like water scarcity and pollution, and most specially, the projected inability to meet the water demands of a rapidly growing population (Gleick, 1995). Population growth linked with increasing demand on water is creating increasing pressure on our current water supply. According to JICA (2002), if business-as-usual scenarios and current population and development growth rates continue, water demand in the Philippines for domestic, agricultural and industrial use will increase from 30 BCM in 1996 to 86.5 BCM in 2025. With the varying availability of water depending on different factors such as precipitation, runoff and evapotranspiration, there is a pressing need to manage the limited water supply and predict future water shortages.

With these issues, a study which will link the relationship of groundwater supply with population growth is crucial. It is important to determine up to when the available water supply can meet the growing needs of an increasing population so that early on, the concerned stakeholders could plan how to circumvent this future scenario.

This study will focus on the assessment of groundwater supply vis-à-vis the household demand of Los Baños, Laguna. Los Baños, as a science community has continuously recorded an increase in population and water demand. With this current scenario, this study aims to identify the relationship of groundwater supply with households water demand. Furthermore, it aims to determine the period when the available groundwater supply can no longer meet the demand of the predicted population of Los Baños. Lastly, this study hopes to come up with recommendations on how to avert this future crisis.

Significance of the Study

This study could help the government of Los Baños and the province of Laguna, together with other concerned stakeholders in coming up with proper management strategies forsustainable use of water resources.

Objectives

This study aims to:

• Describe the water supply situation of Los Baños, Laguna from 1995-2012.

• Explain the water demand of households ofLos Baños, Laguna from 1995-2012.

• Determine the population of Los Baños, Laguna from 1995-2012.

• Identify the relationship of groundwater supply and population growth.

• Forecast the groundwater supply of Los Baños, Laguna up to year 2050 vis-à-vis projected population growth.

I NTRODUCTION

3Assessing current and future groundwater supply

Water Sources

Philippines generates its water supply from a number of different sources which include: rainfall, surface water resources(i.e. rivers, lakes, and reservoirs) and groundwater resources. According to the National Water Regulatory Board (NWRB), Philippines has 18 major river basins and 421 principal river basins.

In terms of groundwater supply, the country has an extensive groundwater reservoir with an aggregate area of about 50,000 sq km. According to the Mines and Geosciences Bureau (MGB) as cited by Greenpeace, there are several groundwater basins underlaid in about 100,000 sq km of various rock formationsin the Philippines. Some of these resources are found inNortheast Luzon, Central Luzon, Laguna Lake basin, Cavite-Batangas-Laguna basin, Southeast Luzon, Mindoro Island, Negros Island, Northeast Leyte, Ormoc-Kananga basin, Agusan-Davao basin, Occidental Misamis basin, and Lanao-Bukidnon-Misamis basin.

Groundwater resources are continuously recharged by rain and seepage from rivers and lakes (PEM, 2003; EMB, 2006).Overall, the Philippines’ total available freshwater resource is at 145,900 MCM/year based on 80 percent probability for surface water, and groundwater recharge or extraction at 20,000 MCM/year (NWRB-SPM, 2003; PEM, 2003; ASEAN, 2005). The report also mentions that groundwater contributes 14% of the total water resource potential of the country (Greenpeace, 2007).

Domestic uses of water

Water for domestic purposes includes water for drinking, use for public services, commercial service establishments (such as hotels), and homes. It is estimated that 325 billion cubic meters of water are used worldwide each year. The world average water use per person is 52 cubic meters per year (Water Dialogues, 2013).

According to MWH Global and American Water Works Association, domestic water use accounts for 69% indoor activities and 31% outdoor activities. Indoor activities include water use for kitchen and toilet. Of this, 14% are wasted to leaks. Meanwhile, 31% are from outdoor activities such as for gardening and cleaning of vehicles, etc.

In Metro Manila, the available estimates of water usage by sources of water and quality of water service show that daily per capita consumption ranges from 20 liters up to 400 liters (JICA, 1992).

Major problems

Disparities between water supply and demand. Water supplyis declining as the world’s population increases. Demands for water in many areas are exceeding supplies. Even though Philippines is endowed withabundantwaterresources,thisdoesnotguaranteesufficientsupply.Distributionofwaterresourcesvary in time and place because of different geographic and climatic conditions in the Philippines (Barba, P, 2003). During dry season, highly populated areas of the country experience water shortage (PEM, 2004).

R eview of Literature

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According to US National Wildlife Federation, “limited supply of freshwater must meet the needs of a human population that has tripled in the last century and continues to grow at almost 80 million people per year.” On the demand side, slower population growth would help reduce pressure on limited water supplies, thus, can provideenough time to develop creative solutions.

Lack of water allocation formula. Sectoralconflictsariseonhowwaterisbeingusedandallocated.Different sectors have varying needs of water and to determine which sector deserves greater share when conflicts in use ofwater rise remain unsolved. In the case of theAngatReservoir,when theMetropolitan Waterworks and Sewerage System (MWSS) withdraws water from the reservoir, portion of the National Irrigators Association’s (NIA) water rights are taken away (Jose, A. and Cruz, N., 1999).

Different sectors are competing for the control and use of available water supply. Big corporations which use huge amount of water in their operation are also competing for supply of water. For example, in San Pablo City, Laguna, farmers and residents complain of declining water availability due to the operation of a mineral water plant by Nestle Philippines, Inc. (Padilla, A., 2007).

Weak water use regulation and enforcement. Though there are a number of agencies involved in implementing rules and regulation related to water use and despite of the number of policies formulated to address this issue,regulation and enforcement are still lacking. A number of private companies are still able to pollute sources of water without being penalized.

Inefficient use of water. Huge amount of water are being put into waste in distribution lines, irrigation canals, and at homes. Another contributing factor to this is the high level of water loss due to leaking pipes and illegal connections.Vast amounts ofwater are alsowasted through inefficiency; growingwater-intensivecrops indryareas;usingdrinkingwater forotherpurposes(e.g.,gardening,flushingtoilets and cleaning of vehicles) where non-potable “grey” water could be used.

Depletion of groundwater resources. Groundwater abstraction is being done in residential areas and industrial areas wherein water providers have failed to provide water services. Indiscriminate groundwater abstraction resulting to salt-intrusion is noticeable in Metro Manila, Cavite, Iloilo, and Cebu.

Threats to water availability. Excessive logging and shifting cultivation in the watersheds have triggered widespread degradation and subsequent erosion and siltation of rivers, lakes, and reservoirs (Santos 1997, as cited in Jose and Cruz, 1999). Most of the watersheds in the Philippines are in critical condition asmanifestedbyrecentandrecurringcalamitiessuchasflashfloodsinSouthernLeyteandNorthernMindanao and an increase in frequency of El Niño events in Luzon which reduces water levels in dams. When remains unaddressed, this could pose serious threats to future water supply.

Fragmented management. This is brought about by a number of different institutions that deal with different water concerns and issues. At present, there are over 30 government agencies and departmentsseparatelydealingwithconcernsonwatersupply, irrigation,hydropower, floodcontrol,pollution,watershedmanagement,etc.Thiscausesanoverlapofworkandconflictsamongagenciesand results in a fractional water management plan that does not adequately meet the requirements for sustainability (Barba, 2005).

5Assessing current and future groundwater supply

Water Providers in the Philippines

Water Districts provide services to 15.3 million people in 700 cities and municipalities outside Manila (Water Dialogues, 2013). As of 2003, there are 574 water districts in the country. These are government-controlled municipal entities.

AGENCY TOTALWater Districts 574Big private operators 8Self provision 9National Government, NGOs, LGUs Water Service As-sociations, and Cooperatives

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Sources of water include water districts, private operators, and cooperatives. Other sources of water include unimproved water sources or roofwater and SSIP-supplied.

Since 2000, percent water coverage has been static. This implies that investments on water sector are unparallel to the increasing demand caused by population growth and aging water systems (Water Dialogues, year).

Projected Future Water Supply Scenarios in the Philippines

According to JICA, if the current water use and demand will continue along with population growth rates and development growth rates, water demand in the country is expected to increase from 30 BCM in 1996 to 86.5 BCM in 2025.

Projected increase in water demand from 1996-2005 (JICA, )

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Figure 1. DPSIR framework for groundwater supply.

Thisframeworkaimstodefinetheproblemonsustaininggroundwatersupplyvis-à-visincreasingwater demand of households. Generally, it describes the issue on groundwater supply. Water supply problems arise from the increase in demand thereby exceeding the available supply for that time. Through this framework, key concepts and keywords related to the problem are listed to identify their links and relationships.

For the drivers, our drivers include population dynamics, households and use of water. For the pressures, human activities that create stress on the water supply includes: domestic water consumption, water abstraction, deforestation,urbanization and climate change. With these pressures, the state is characterized by groundwater availability and water quality. The impacts of the pressures and drivers include: depletion of groundwater supply, decrease in water supply and loss of amenity. To address these impacts, the responses include: policy formulation, infrastructure development through creation ofadditionalpumps,efficientwaterallocation,anddemandmanagement.

T heoretical Framework

7Assessing current and future groundwater supply

Data gathering

Primary and secondary data were collected in this study. Data on the water supply scenario from 1995-2012 were gathered from the Laguna Water District while population data will be gathered from the Municipality of Los Baños. Other secondary data were collected from books, journals and reports to generate data that could help understand the present water scenario in the Philippines and to provide informationthatcouldsupportandstrengthenthefindingsofthestudy.

Data analysis

For assessing past, present and future water supply and demand, population and production data were collected. The population and production data were analyzed on a yearly basis from 1995-2012 and were interpreted graphically to understand the dynamics of population and water production.

When a series of observations are arranged with reference to their occurrences in a systematic order, the resulting series is called a time series and conversely, a steady increase or decrease of the time series is known as trend (Patra, 2001). In Time Series Models the past behavior of time series data set is examined to infer something about its future behavior (Gupta, 2008). In this study the trend of population for the demand and the production for the supply was calculated using average values of populationandproductionusingMicrosoftOfficeExcel2007.

POPULATION DYNAMICS IN LOS BAÑOS, LAGUNA

Description of the study site

LosBañosisafirstclasscommunitywithatotallandareaof5,422has.Itiscomposedof14barangays. It is bordered on the south and southwest by Mt. Makiling, on the north by Laguna de Bay, on the northwest by Calamba City and on the east by the town of Bay.

Los Baños was declared as a science city because of the various research and science institutions found in the area. It houses the University of the Philippines at Los Baños (UPLB) and various international and national research institutions like the Ecosystems Research and Development Bureau (ERDB), ASEAN Centre of Biodiversity (ACB), Forest Products Research and Development Institute (FPRDI), International Rice Research Institute (IRRI), International Potato Center (IPC), Biotech, PCARRD, PCAMMRD, Institute of Plant Breeding, among others.

Aside from the research institutions in the area, there are also 21 places along with 42 resorts that can be found in Los Baños (EIA Report, 2012). There are also historical landmarks, museums, botanical gardens, shrines and recreation areas that are found in the area. Also situated in Los Baños, Laguna is the Makiling Forest Reserve which was recently declared as an ASEAN natural heritage park.

Methodology

R esults and Discussion

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Figure 2. Map of Los Baños, Laguna (Wikipedia, 2013).

Socio-economic profile of Los Baños, Laguna

AccordingtotheSocio-EconomicProfileandPhysicalProfileofLosBañosin2007,LosBañoshasa total population of 85, 722 comprised of 21,031 households (Table 1). From 2007 to 2010, there was an increase of 16,162 in its total population (Census of Population and Housing, 2010).

As of May 2010, the total population of Los Baños is 101,884 (NSCB). The average household size is 4.14 (BMIS, 2005). It has a total population density of 1,451 per square kilometer. As of 2000, its growth rate is estimated at 2.93% (NSO, 2000). Half of the population is comprisedof female.

Table 1. Population per barangay of Los Baños, Laguna.

BARANGAY HOUSEHOLDS MALE FEMALE TOTAL

Anos 1,588 3,209 3,398 6,607

Bagong Silang 159 317 319 636

Bambang 1,719 3,492 3,439 6,931

Batong Malake 2,884 5,592 5,746 11,338

Baybayin 379 711 784 1,495Bayog 1,747 3,635 3,676 7,311Lalakay 986 2,071 1,987 4,058Maahas 1,304 2,632 2,571 5,203Malinta 1,385 2,832 2,877 5,709Mayondon 3,371 6,822 6,788 13,610Putho-Tuntungin 1,559 3,196 3,329 6,525San Antonio 2,404 4,725 4,881 9,606Tadlac 691 1,437 1,585 3,022Timugan 853 1,864 1,807 3,671Total 21,031 42,535 43,187 85,722

Source:Socio-EconomicandPhysicalProfile,2007

9Assessing current and future groundwater supply

The most populated barangay is Mayondon with a population of 13, 610 followed by Batong Malaki with 11, 338. The least populated barangay is Bagong Silang with only 636 individuals. Bagong Silang is situated in the Makiling Forest Reserve. Most of the families in the area used to be informal settlers that inhabit the area.

The ratio of female to male is 1:1. Fifty percent (50.38) or 43, 187 of the total population are female. Table 2 shows the ratio of male to female population.As to the age of population, Los Baños can be considered as a fairly young community. Majority of the population is in the age group of 0-29 years old. This is attributed to the number of work opportunities available in the area. Meanwhile, there are 594 individuals aged 80 and up.

Table 2. Total population of Los Baños by age group and sex.

AGE MALE FEMALE TOTAL0-4 3,998 3,629 7,6275 to 9 4,916 4,466 9,38210 to 14 4,286 4,058 8,34415 -19 4,223 4,288 8,51120-24 4,140 4,610 8,75025-29 4,039 4,250 8,28930-34 3,260 3,294 6,55435-39 2,960 3,028 5,98840-44 2,645 2,713 5,35845-49 2,267 2,353 4,62050-54 1,878 1,974 3,85255-59 1,408 1,428 2,83660-64 866 971 1,83765-69 686 781 1,46770-74 433 554 98780+ 199 395 594All Ages 42,535 43,187 85,722

Source: BMIS, 2007

For the fertility and mortality rate of Los Baños, Los Baños has 0.60% mortality rate in 2007 compared to its fertility rate which is 2.15% (BMIS, 2007). Low mortality rate in Los Baños can be attributed to the medical services and assistance being provided by the local government and other institutions (EIA Report, 2012). This implies that Los Baños is a growing community because of its 2.93% growth rate (NSO, 2000). Fertility and mortality rate of Los Baños is shown in Table 3.

Table 3. Fertility and mortality rate of Los Baños from 2006-2007.

YEAR POPULATION* FERTILITY

NUMBER

MORTALITY

NUMBER

FERTILITY

RATE (%)

MORTALITY

RATE (%) 2006 85,586 2,067 546 2.41 0.63 2007 88,093 1,902 537 2.15 0.60

Source: NSO, 2000

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For the number of houses in Los Baños, there are 18,882 houses as per record of the BMIS in 2006 (Table 4). Majority of the houses are found in the barangay of Mayondon. It is composed of 2,893 houses. It is closely followed by barangay Batong Malake with 2,727 houses; San Antonio with 2,136 and Bayog with 1,574. The least number of houses could be found in the barangays of Bagong Silang (144), Baybayin (330) and Tadlac (613).

Table 4. Number of houses in Los Baños.

BARANGAY NO. OF HOUSESAnos 1,469Bagong Silang 144Bambang 1,425Batong Malake 2,727Baybayin 330Bayog 1,574Lalakay 869Maahas 1,186Malinta 1,228Mayondon 2,893Putho-Tuntungin 1,454San Antonio 2,136Tadlac 613Timugan 834

Total 18,882

Source: BMIS, 2007

Some of the houses in Los Baños are commercial/industrial agricultural houses, duplexes, bungalows, extensions, apartments, 1-3 storey’s type and semi-mansions.

In terms of income, the average monthly income of the people in Los Baños is P7,652.26 (BMIS, 2006). This is below the poverty threshold in Region 4 which is P12,452. Table 6 presents the monthly income of the heads of the family in Los Baños.

Table 6. Monthly income of heads of family in Los Baños.

INCOME NO. OF HEAD OF THE FAMILYBelow 1, 999 2,2862,000-2,999 2,7563,000-3,999 3,2344,000-4,999 2,2095,000-9,999 7,47610,000-14,999 2,48115,000-19,999 1,04520,000 above 1,162Total 22,649

Source: BMIS, 2007

11Assessing current and future groundwater supply

WATER SUPPLY IN LOS BAÑOS, LAGUNA

Water sources of Los Baños

The primary source of water in Los Baños is the Laguna Water District (LWD). By virtue of PD 198 or the Provincial Local Water Utilities Act of 1973, LWD has the authority to provide potable water to communities and at the same time control and regulate the development of water resources within its area of jurisdiction.

Formed in 1977, it was originally called Los Baños Waterworks and was later renamed Los Baños Water District. With the annexation of the towns of Bay and Calauan it was called the Laguna Water District.

As of 2012 record, it services 87,300 populations of Los Baños divided into: residential, governmentandcommercialoffices.Thetotalwaterconsumptionisat6,988,415cubicmeters.Asidefrom the water from LWD, other sources of water include deep well, artesian well, creeks, river, spring and lakes (EIA Report, 2012).

Water Pump Stations in Los Baños

There are nine active pump stations in Los Baños situated in different barangays of Los Baños (Figure 3 and Table 7). These include the barangays of Baybayin, Bayog, Timugan, Lalakay, Maahas, Batong Malake, and Putho Tuntungin. The water sources are mostly from groundwater.

Table 7. Pump stations in Los Baños, Laguna.

PUMP STATIONS WATER SOURCE LOCATION (BRGY) YEAR OF OPERATIONVILLEGAS 1 Groundwater Baybayin 1959 -2010VILLEGAS 2 Groundwater Baybayin 2010 – presentLOPEZ HEIGHTS Groundwater Timugan 1987 – presentLALAKAY Groundwater Lalakay 2004 – presentMAAHAS Groundwater Maahas 2002 – presentMALINTA Groundwater Malinta 1980 – 1995UMALI Groundwater Batong Malake 1973 – presentBAYOG Groundwater Bayog 2010 – presentVEGA Groundwater Batong Malake 2003 – presentSTA. RITA Groundwater San Antonio 1998 – 2010UPCO Groundwater Batong Malake 1995 – presentSTP Groundwater Putho Tuntungin 2001 – presentDAMPALIT Spring Lalakay 1950’s -2006

Source: Laguna Water District, 2013

The total rated capacity of existing and active LWD pump stations is 6,940 gallons per minute or is equivalent to 13,807,910.275 cubic meters per year of water that can be supplied to the needs of the present and future population.

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Table 8. Rated Capacity of Pump stations.

PUMP STATIONS RATED CAPACITY (Gallons per Minute)

VILLEGAS 2 1,400LOPEZ HEIGHTS 500LALAKAY 520MAAHAS 1,270UMALI 500BAYOG 1,200VEGA 1,000UPCO 350STP 200

Source: Laguna Water District, 2013

Figure 3. Los Baños Water DistributionSystem showing Pump stations (LWD, 2013)

13Assessing current and future groundwater supply

Population and Population Served Los Baños, Laguna (1995-2050) - LWD

Figure 4 shows the trend in the population of Los Baños and the population served by LWD. Also shown are the projected population and the future service connections. Population in Los Baños is 71,673 in 1995 and it shoots up to 107,942 people as of 2012 for an increase of 33.6% for a period of 17 years and with present trend and a growth rate of 2.93 the population is predicted to be tripled to 323,433 by the year 2050.

As the population increased the population served by LWD increases also from 45,580 in 1995 to 87,300 in 2012. These were taken from the number of service connections from the said years 9,741 and 18,311 respectively. LWD used a factor of 5 individuals per household or service connections.

With the increasing population and the trend in the number of service connections by the year 2036 all the population of Los Baños will have an access to the water service of LWD as depicted in Figure 4.

Water demand and Water production of Los Baños

In terms of production and demand (Figure 5), Los Baños produces 5,022,499.65 cubic meters of water in 1995. This is greater than the demand in the study area which is only 4,970,522.55 cubic meters. From 1995 to 2012, 17 years after, the production of water increased to 8,720,196.27 cubic meters this is to answer the increased to the demand by 7,485,769.60 cubic meters. With the increasing demand LWD also increase its production to answer the population’s need for safe and potable for their well-being. Based from the trends from 1995-2012 in every increase in demand there is an increase of 1.42% for the production of water.

By 2050, with the increasing population the demand will escalate to a total of 22,430,107.94 cubic meters and LWD should be able to produce a total of 24,823,004.69 cubic meters of water. With the current total rated capacity or the maximum sustainable yield of 13,807,910.275 cubic meters, the existing pump stations of LWD will only be able to support water dependent human activities by 2029.

CONCLUSION AND RECOMMENDATIONS

Based on the results of this study, the following conclusion and recommendations were drawn:

1. Water, as a prime necessity, though renewable is not constant from year to year or month to month. Precipitation, runoff, and evaporation all change from year to year, in some years less water will be available for allocation than in others.

2. In year 2029, groundwater available at the 9 pumping stations in Los Baños may no longer be sufficienttomeetthehousehold’swaterdemandduringthattime.

3. More research and studies should be funded for the determination of total full potential of groundwater resources in Los Baños.

4. To prevent depletion of groundwater supply and increase the water supply, the Water District of Los Baños has to construct new pumps that could provide new sources of water.

C onclusion and Recommendations

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Figure 4. Population and Population Served.

Figure 5. Water Demand and Production.

15Assessing current and future groundwater supply

5. ThegovernmentofLosBañoshastofindwaystofacilitategroundwaterrechargeatafasterway.Thismaymean creation of flood control infrastructures that couldmitigate factors thatslows down groundwater recharge.

6. Policies that could address the causes of slower groundwater recharge such as: deforestation and increasing number of residential areas and road infrastructures could also be created.

7. Lesser per capita water consumption and leakage control should also be promoted.

REFERENCES

Census of Population and Housing. 2010.

Dano, A. et al. 2010. Vulnerability assessment of Mt. Makiling Watershed. Ecosystems Research and Development Bureau. Los Baños, Laguna.

EIA Report of the Proposed UPLB IT Park. Unpublished Report. 2012. School of Environmental Science and Management. UPLB. Los Baños, Laguna.

Gleick, P. 1995. Human Population andWater: To the Limits in the 21st Century. Pacific Institutefor Studies in Development, Environment and Security. Oakland, California. [cited 2013 August 11]. Retrieved at http://www.aaas.org/international/ehn/fisheries/gleick.htm

Gupta S. P. and Gupta M. P. 2008. Business Statistics. Sultan Chand & Sons Educational Publishers, New Delhi

Greenpeace. 2007. The state of water in the Philippines. Quezon City, Philippines. Retrieved at _____________________________________ on July 29, 2013.

Laguna Water District. 2013

National Statistics Coordination Board. n/a. Philippine Water Resources. [cited 2013 August 11]. Available from http:www.nscb.gov.ph/peenra/Publications/asset/water.pdf

National Water Resources Council. 1982. Rapid Assessment of Water Supply Sources. Province of Laguna. Report No. 36 Volume 24.

Patra, K. C. 2001. Hydrology and water resources engineering. New Delhi: Narosa Publishing House

Socio-EconomicandPhysicalProfileofLosBaños,Laguna.2007.

The Water Dialogues. The Philippine Water Situation. [cited 2013 August 11]. Retrieved at http://www.waterdialogues.org/documents/PhilippinesCountryContext.pdf