Northern New England Tableau User Group (TUG) May 2024
San Juan - Ecological Profile (2021).pdf
1. CITY OF SAN JUAN
ECOLOGICAL PROFILE 2021
Prepared by the City Planning and Development Office
with assistance from Gurin Urban Design and Concepts, Inc.
2. i || CITY OF SAN JUAN
VISION
San Juan City: a leader in integrity and excellence in local governance
A safe, inclusive, progressive, sustainable, and resilient community of civic-minded and
law-abiding citizens, as defenders of democracy inspired by its historical significance in the
fight for freedom, through efficient and transparent leadership towards a "Makabagong San Juan".
MISSION
To provide quality and effective social services, pursue sustainable, inclusive, and
equitable economic growth, and promote ecological balance through responsive,
transparent, efficient, and technologically advanced governance in partnership with
an empowered people towards achieving the city of excellence.
3. ECOLOGICAL PROFILE 2021 || ii
Table of Contents
CHAPTER 1. HISTORY ........................................................................................................................................................................................................ 1
CHAPTER 2. GEO-PHYSICAL ENVIRONMENT.................................................................................................................................................................. 2
2.1. Geographical Location......................................................................................................................................................................................................... 2
2.2. Political Boundaries and Land Area..................................................................................................................................................................................... 2
2.3. Topography ......................................................................................................................................................................................................................... 7
2.3.1. Elevation..................................................................................................................................................................................................................... 7
2.3.2. Slope .......................................................................................................................................................................................................................... 7
2.4. Geology............................................................................................................................................................................................................................... 7
2.4.1. Soils............................................................................................................................................................................................................................ 8
2.4.2. Land Capability Classes.............................................................................................................................................................................................. 8
2.5. Land Resources ................................................................................................................................................................................................................ 13
2.5.1. Land Classification.................................................................................................................................................................................................... 13
2.5.2. Land Cover ............................................................................................................................................................................................................... 13
2.5.3. Existing General Land use........................................................................................................................................................................................ 13
2.5.4. Land Use Trends and Pattern ................................................................................................................................................................................... 14
2.6. Water Resources............................................................................................................................................................................................................... 17
2.6.1. Surface Waters......................................................................................................................................................................................................... 17
2.6.2. Natural Drainage Pattern .......................................................................................................................................................................................... 17
2.6.3. Groundwater Sources............................................................................................................................................................................................... 17
2.6.4. Water Quality Management Area.............................................................................................................................................................................. 17
2.7. Climate .............................................................................................................................................................................................................................. 20
2.7.1. Atmospheric Temperature......................................................................................................................................................................................... 20
2.7.2. Relative Humidity...................................................................................................................................................................................................... 20
2.7.3. Rainfall...................................................................................................................................................................................................................... 20
2.7.4. Prevailing Winds ....................................................................................................................................................................................................... 20
2.7.5. Tropical Cyclone ....................................................................................................................................................................................................... 20
2.7.6. Climate Change Projections...................................................................................................................................................................................... 22
4. iii || CITY OF SAN JUAN
2.7.7. Climate Change Impacts........................................................................................................................................................................................... 22
2.7.7.1. Extreme Rainfall........................................................................................................................................................................................... 22
2.7.7.2. Temperature Changes ................................................................................................................................................................................. 22
2.8. Natural Hazards................................................................................................................................................................................................................. 24
2.8.1. Earthquake Hazards ................................................................................................................................................................................................. 24
2.8.2. Liquefaction Potential................................................................................................................................................................................................ 24
2.8.3. Hydrometeorological Hazards................................................................................................................................................................................... 25
2.8.3.1. Flood Hazard ............................................................................................................................................................................................... 25
2.8.3.2. Rain-induced Landslide................................................................................................................................................................................ 26
2.8.4. Severe Wind Hazard................................................................................................................................................................................................. 26
2.9. Environmental Concerns ................................................................................................................................................................................................... 38
2.9.1. Air Quality ................................................................................................................................................................................................................. 38
2.9.2. Water Quality............................................................................................................................................................................................................ 38
2.10. Environment Analysis Matrix.............................................................................................................................................................................................. 38
CHAPTER 3. DEMOGRAPHIC STUDIES........................................................................................................................................................................... 39
3.1. Population Composition..................................................................................................................................................................................................... 39
3.1. Population Distribution....................................................................................................................................................................................................... 42
3.2. Population Changes .......................................................................................................................................................................................................... 44
3.2.1. Historical Growth of Population................................................................................................................................................................................. 44
3.2.2. Other Population Characteristic ................................................................................................................................................................................ 44
3.2.3. Marital Status............................................................................................................................................................................................................ 44
3.2.4. Religious Affiliation.................................................................................................................................................................................................... 45
3.2.5. Literacy Rate............................................................................................................................................................................................................. 45
3.2.6. Labor Force .............................................................................................................................................................................................................. 46
3.2.7. Registered Voters ..................................................................................................................................................................................................... 48
3.3. Population Projections and Estimates................................................................................................................................................................................ 48
3.4. Projected Total Population per Barangay........................................................................................................................................................................... 48
5. ECOLOGICAL PROFILE 2021 || iv
CHAPTER 4. SOCIAL SECTOR STUDY............................................................................................................................................................................ 50
4.1. Social Sub-Sector: EDUCATION ....................................................................................................................................................................................... 50
4.2. Social Sub-Sector: HEALTH AND SANITATION ............................................................................................................................................................... 56
4.2.1. Existing Situation ...................................................................................................................................................................................................... 56
4.2.2. Fertility, Morbidity and Mortality................................................................................................................................................................................. 59
4.2.3. Health-related Projects.............................................................................................................................................................................................. 60
4.2.4. Cemeteries and Memorial Parks............................................................................................................................................................................... 60
4.2.5. Sanitation.................................................................................................................................................................................................................. 60
4.2.6. Solid Waste Management......................................................................................................................................................................................... 62
4.2.7. Health and Sanitation Analysis Matrix....................................................................................................................................................................... 64
4.3. Social Sub-Sector: HOUSING ........................................................................................................................................................................................... 65
4.3.1. Existing Situation ...................................................................................................................................................................................................... 65
4.3.2. Inventory of Residential Subdivisions and Condominium Projects ............................................................................................................................ 66
4.3.3. Resettlement Areas .................................................................................................................................................................................................. 67
4.3.4. Housing Analysis Matrix............................................................................................................................................................................................ 69
4.4. Social Sub-Sector: SOCIAL WELFARE SERVICES .......................................................................................................................................................... 70
4.4.1. Existing Situation ...................................................................................................................................................................................................... 70
4.4.2. Social Welfare Analysis Matrix.................................................................................................................................................................................. 75
4.5. Social Sub-Sector: PROTECTIVE SERVICES................................................................................................................................................................... 76
4.5.1. Existing Situation ...................................................................................................................................................................................................... 76
4.5.2. Types and Volume of Crime...................................................................................................................................................................................... 79
4.5.3. Fire Incidents ............................................................................................................................................................................................................ 84
4.5.4. Police and Fire Personnel Requirements.................................................................................................................................................................. 85
4.5.5. Disaster Risk Reduction and Management Office ..................................................................................................................................................... 85
4.5.6. Protective Services Analysis Matrix .......................................................................................................................................................................... 86
4.6. Social Sub-Sector: SPORTS AND RECREATION............................................................................................................................................................. 87
4.6.1. Existing Situation ...................................................................................................................................................................................................... 87
4.6.2. Sports and Recreation Analysis Matrix...................................................................................................................................................................... 89
6. v || CITY OF SAN JUAN
CHAPTER 5. ECONOMIC SECTOR STUDY...................................................................................................................................................................... 90
5.1. Economic Sub-Sector: COMMERCE AND TRADE............................................................................................................................................................ 90
5.1.1. Commerce and Trade Analysis Matrix ...................................................................................................................................................................... 93
5.2. Economic Sub-Sector: INDUSTRY.................................................................................................................................................................................... 95
5.2.1. Existing Situation ...................................................................................................................................................................................................... 95
5.2.2. Problem-Solution Finding Matrix ............................................................................................................................................................................... 97
5.3. Economic Sub-Sector: TOURISM...................................................................................................................................................................................... 98
5.3.1. Existing Situation ...................................................................................................................................................................................................... 98
5.3.2. Tourism Analysis Matrix.......................................................................................................................................................................................... 105
CHAPTER 6. INFRASTRUCTURE SECTOR STUDY....................................................................................................................................................... 106
6.1. Infrastructure Sub-Sector: TRANSPORTATION .............................................................................................................................................................. 106
6.1.1. Roads and Bridges ................................................................................................................................................................................................. 106
6.1.2. Public Transportation.............................................................................................................................................................................................. 119
6.1.3. Road crashes.......................................................................................................................................................................................................... 122
6.1.4. Transport Analysis Matrix........................................................................................................................................................................................ 125
6.2. Infrastructure Sub-Sector: ELECTRICITY AND POWER................................................................................................................................................. 128
6.2.1. Existing Situation .................................................................................................................................................................................................... 128
6.2.2. Electricity and Power Analysis Matrix...................................................................................................................................................................... 128
6.3. Infrastructure Sub-Sector: WATER SUPPLY AND DISTRIBUTION................................................................................................................................. 130
6.3.1. Existing Situation .................................................................................................................................................................................................... 130
6.3.2. Water Analysis Matrix ............................................................................................................................................................................................. 145
6.4. Infrastructure Sub-Sector: INFORMATION AND COMMUNICATION TECHNOLOGY .................................................................................................... 146
6.4.1. ICT Analysis Matrix................................................................................................................................................................................................. 149
CHAPTER 7. SPECIAL AREAS STUDIES....................................................................................................................................................................... 151
7.1. Climate and Disaster Risk Assessment ........................................................................................................................................................................... 151
7.1.1. Disaster Risk Assessment Process and Benchmarks ............................................................................................................................................. 151
7.1.2. Hazard Magnitude Scores....................................................................................................................................................................................... 151
7.1.3. Exposure Scores..................................................................................................................................................................................................... 153
8. vii || CITY OF SAN JUAN
List of Tables
Table 2-1. Comparison of Land Areas of the Cities and Municipalities of Metro Manila................................................................................................................ 2
Table 2-2. Land Area per Barangay............................................................................................................................................................................................. 3
Table 2-3. Elevation Area Tabulation........................................................................................................................................................................................... 7
Table 2-4. Slope Distribution in San Juan .................................................................................................................................................................................... 7
Table 2-5. Land Uses in San Juan, 2013 and 2020 ................................................................................................................................................................... 14
Table 2-6. Estimated Lengths of San Francisco-San Juan River ............................................................................................................................................... 17
Table 2-7. CLIRAM of the Projected Seasonal Change in Mean Temperature (in degree Celsius) in the mid-21st century (2036-2065) for Metro Manila......... 23
Table 2-8. CLIRAM of the Projected Seasonal Change in Total Rainfall (in millimeters) in the mid-21st century (2036-2065) for Metro Manila......................... 23
Table 2-9. Liquefaction Areas in San Juan................................................................................................................................................................................. 25
Table 2-10. Flood Susceptibility Areas in San Juan ..................................................................................................................................................................... 25
Table 2-11. 100 Return Period – Severe Wind............................................................................................................................................................................. 26
Table 3-1. Population of National Capital Region – 2000, 2010, and 2015................................................................................................................................. 39
Table 3-2. Population by Barangay and Average Household Size, 2010 and 2015.................................................................................................................... 40
Table 3-3. Population Distribution by Age Group and Sex, 2015................................................................................................................................................ 41
Table 3-4. Population Composition by School-Age, Working-Age, Dependent-Age Group and Sex, 2015................................................................................. 42
Table 3-5. Population Density per Barangay.............................................................................................................................................................................. 43
Table 3-6. Historical Growth of Population................................................................................................................................................................................. 44
Table 3-7. Total Population 10 Years Old and Over by Sex and Marital Status, 2015................................................................................................................ 44
Table 3-8. Population by Religious Affiliation, 2015 ................................................................................................................................................................... 45
Table 3-9. Literacy Rate of Population 10 Years Old and Over by Sex, 2015 ............................................................................................................................ 45
Table 3-10. Household Population 5 Years Old and Over by Highest Educational Attainment, 2015 ........................................................................................... 45
Table 3-11. Population by Sex and Employment Status, 2015..................................................................................................................................................... 46
Table 3-12. Total Gainful Workers by Sex by Major Occupation Classification, 2015................................................................................................................... 47
Table 3-13. Registered Voters by Sex, 2019................................................................................................................................................................................ 48
Table 3-14. Voter Turnout, 2019.................................................................................................................................................................................................. 48
Table 3-15. Projected Total Population and Household Population.............................................................................................................................................. 48
Table 3-16. Projected Total Population by Barangay, 2020-2045 ................................................................................................................................................ 49
Table 4-1. Public schools by level, facilities, and condition ........................................................................................................................................................ 51
Table 4-2. Private schools by level, facilities, and condition ....................................................................................................................................................... 52
Table 4-3. Tertiary and technical / vocational schools by type.................................................................................................................................................... 53
Table 4-4. Historical elementary enrolment in public schools by level for the past five (5) school years..................................................................................... 53
Table 4-5. Historical SPED enrolment in public schools by level for the past five (5) school years (SPED)................................................................................ 54
Table 4-6. Historical secondary enrolment in public schools by level for the past five (5) school years...................................................................................... 54
Table 4-7. Total enrolment in tertiary and technical vocational schools for the past five (5) school years................................................................................... 54
Table 4-8. Medical Health Facilities and Personnel, 2020.......................................................................................................................................................... 57
Table 4-9. General Health Situation, 2015-2019 ........................................................................................................................................................................ 59
Table 4-10. Ten Leading Causes of Morbidity, 2019.................................................................................................................................................................... 59
Table 4-11. Ten Leading Causes of Mortality, 2019..................................................................................................................................................................... 59
9. ECOLOGICAL PROFILE 2021 || viii
Table 4-12. Households Access to Sanitation Facilities, 2014 ..................................................................................................................................................... 61
Table 4-13. Solid Waste Generation ............................................................................................................................................................................................ 62
Table 4-14. Methods of Waste Disposal/Treatment ..................................................................................................................................................................... 63
Table 4-15. Types of Housing Units............................................................................................................................................................................................. 65
Table 4-16. Sources of Drinking Water, 2015 .............................................................................................................................................................................. 65
Table 4-17. Sources of Water for Cooking, 2015 ......................................................................................................................................................................... 65
Table 4-18. Types of fuel used for lighting and cooking, 2015 ..................................................................................................................................................... 66
Table 4-19. Residential Developments ........................................................................................................................................................................................ 66
Table 4-20. Resettlement facilities outside of San Juan City........................................................................................................................................................ 68
Table 4-21. Social Welfare Resolutions and Ordinances ............................................................................................................................................................. 70
Table 4-22. Social Welfare Facilities............................................................................................................................................................................................ 73
Table 4-23. Protective Services by Facilities, 2020...................................................................................................................................................................... 77
Table 4-24. Top Crimes, 2016-2020 ............................................................................................................................................................................................ 79
Table 4-25. Status of cases ......................................................................................................................................................................................................... 79
Table 4-26. Crimes committed, 2016-2020 .................................................................................................................................................................................. 80
Table 4-27. Fire Incidents in the last five years, 2016-2020 ......................................................................................................................................................... 84
Table 4-28. Projected Population and Required No. of Personnel ............................................................................................................................................... 85
Table 4-29. Sports and Recreation Services by Facilities, 2020................................................................................................................................................... 87
Table 5-1. Business Permits Granted for the Past Five Years 2015-2019.................................................................................................................................. 90
Table 5-2. Inventory of Commercial Establishment by Economic Activities................................................................................................................................ 92
Table 5-3. Employment by Type/Classification/Type of Business and Trade ............................................................................................................................. 92
Table 5-4. Historical data on industrial areas ............................................................................................................................................................................. 95
Table 5-5. Local Revenue and Industrial Establishment............................................................................................................................................................. 95
Table 5-6. Inventory of Local Policies in relation to the Economic Sector (2018-2020)............................................................................................................... 96
Table 5-7. Cultural and tourism activities / festivals.................................................................................................................................................................... 99
Table 5-8. Accessibility of existing tourism establishments and tourist attractions (cultural)*.................................................................................................... 100
Table 5-9. Accessibility of existing tourism establishments and tourist attractions (non-cultural)*............................................................................................. 101
Table 5-10. Inventory of tourism establishments........................................................................................................................................................................ 103
Table 5-11. Inventory of tourism establishments and support facilities....................................................................................................................................... 104
Table 6-1. Inventory of Roads by System Classification (National) and Type of Pavement...................................................................................................... 107
Table 6-2. Inventory of Roads with Classification and Road Surface Type............................................................................................................................... 108
Table 6-3. Inventory of bridges by barangay, type, capacity and condition............................................................................................................................... 118
Table 6-4. Inventory of transportation terminals by location and condition ............................................................................................................................... 120
Table 6-5. Inventory of public and land transport vehicles by type and service route ............................................................................................................... 121
Table 6-6. Other modes of transport and facilities.................................................................................................................................................................... 122
Table 6-7. Road accidents by location, nature, and frequency for the past five years .............................................................................................................. 123
Table 6-8. Transport-related projects, approved / funded for implementation........................................................................................................................... 124
Table 6-9. Households served with electricity for the past three years..................................................................................................................................... 128
Table 6-10. Projected number of connections by type of users and average consumption ........................................................................................................ 128
10. ix || CITY OF SAN JUAN
Table 6-11. Inventory of combined sewage and drainage pipes by location, year, type, size, and condition .............................................................................. 131
Table 6-12. Water consumption by type of consumer (2009-2011) ............................................................................................................................................ 143
Table 6-13. List of existing flood control facilities ....................................................................................................................................................................... 144
Table 6-14. Cell site network by barangay (2012)...................................................................................................................................................................... 146
Table 7-1. Hazard magnitude scores for flood ......................................................................................................................................................................... 152
Table 7-2. Hazard magnitude scores for rain-induced landslide and liquefaction ..................................................................................................................... 152
Table 7-3. Exposure score parameters .................................................................................................................................................................................... 153
Table 7-4. Population exposure scores - Flood........................................................................................................................................................................ 154
Table 7-5. Population exposure scores – Rain-induced landslide ............................................................................................................................................ 156
Table 7-6. Population exposure scores – Liquefaction............................................................................................................................................................. 156
Table 7-7. Critical facilities exposure scores ............................................................................................................................................................................ 160
Table 7-8. Urban uses exposure scores - Flood....................................................................................................................................................................... 169
Table 7-9. Urban Uses Exposure Scores – Rain-induced Landslide ........................................................................................................................................ 174
Table 7-10. Urban Uses Exposure Scores – Liquefaction.......................................................................................................................................................... 174
Table 7-11. Population Sensitivity Indicators.............................................................................................................................................................................. 179
Table 7-12. Critical Facilities Sensitivity Indicators..................................................................................................................................................................... 179
Table 7-13. Lifeline utilities sensitivity indicators ........................................................................................................................................................................ 180
Table 7-14. Urban uses sensitivity indicators............................................................................................................................................................................. 180
Table 7-15. Population adaptive capacity indicators .................................................................................................................................................................. 181
Table 7-16. Critical Facilities Adaptive Capacity Indicators ........................................................................................................................................................ 182
Table 7-17. Urban uses adaptive capacity indicators................................................................................................................................................................. 183
Table 7-18. Likelihood of occurrence score matrix..................................................................................................................................................................... 184
Table 7-19. Vulnerability Score.................................................................................................................................................................................................. 184
Table 7-20. Risk Score Matrix.................................................................................................................................................................................................... 185
Table 7-21. Population Risk Scores for Flood............................................................................................................................................................................ 186
Table 7-22. Population Risk Scores for Rain-induced Landslide................................................................................................................................................ 188
Table 7-23. Population Risk Scores for Liquefaction.................................................................................................................................................................. 188
Table 7-24. Critical Facilities Risk Scores for Flood ................................................................................................................................................................... 192
Table 7-25. Critical Facilities Risk Scores for Rain-induced Landslide ....................................................................................................................................... 199
Table 7-26. Critical Facilities Risk Scores for Liquefaction......................................................................................................................................................... 199
Table 7-27. Urban Uses Risk Scores for Flood.......................................................................................................................................................................... 205
Table 7-28. Urban Uses Risk Scores for Rain-induced Landslide.............................................................................................................................................. 210
Table 7-29. Urban Uses Risk Scores for Liquefaction................................................................................................................................................................ 210
Table 7-30. Decision Areas for Population................................................................................................................................................................................. 217
Table 7-31. Decision Areas for Critical Facilities ........................................................................................................................................................................ 219
Table 7-32. Decision Areas for Urban Uses............................................................................................................................................................................... 223
11. ECOLOGICAL PROFILE 2021 || x
List of Figures
Figure 3-1. NCR Total Population by City/ Municipality, 2015 ........................................................................................................................................................ 40
Figure 3-2. Population Distribution by Age Group and Sex, 2015................................................................................................................................................... 41
Figure 6-1. Bus route 10 from Cubao to Doroteo Jose (2020)...................................................................................................................................................... 121
Figure 6-2. Bus route 11: Gilmore – Taytay (2020) ...................................................................................................................................................................... 121
Figure 8-1. Organizational Chart, City of San Juan...................................................................................................................................................................... 227
Figure 8-2. Total Revenue, 2018 and 2019.................................................................................................................................................................................. 228
Figure 8-3. Locally Sourced Revenue per Capita......................................................................................................................................................................... 228
Figure 8-4. IRA-Dependency Ratio, 2018 .................................................................................................................................................................................... 229
Figure 8-5. IRA-Dependency Ratio, 2019 .................................................................................................................................................................................... 229
Figure 8-6. Personnel Expenditures Ratio, 2018 and 2019 .......................................................................................................................................................... 230
Figure 8-7. Total Expenditure Per Capita, 2018 and 2019 ........................................................................................................................................................... 230
Figure 8-8. Local Legislative Measures Adopted, 2018 and 2019 ................................................................................................................................................ 231
12. xi || CITY OF SAN JUAN
List of Maps
Map 2-1. Location Map of the City of San Juan ............................................................................................................................................................................ 4
Map 2-2. Political Boundaries Map of the City of San Juan........................................................................................................................................................... 5
Map 2-3. City Districts Map of San Juan....................................................................................................................................................................................... 6
Map 2-4. Contour Map.................................................................................................................................................................................................................. 9
Map 2-5. Slope Map ................................................................................................................................................................................................................... 10
Map 2-6. Geology Map ............................................................................................................................................................................................................... 11
Map 2-7. Soil Map....................................................................................................................................................................................................................... 12
Map 2-8. Satellite Image of San Juan ......................................................................................................................................................................................... 15
Map 2-9. Existing Land Use Map of San Juan ............................................................................................................................................................................ 16
Map 2-10. Hydrology .................................................................................................................................................................................................................... 19
Map 2-11. Groundwater Potential ................................................................................................................................................................................................. 19
Map 2-12. Climate Map of San Juan............................................................................................................................................................................................. 21
Map 2-13. Location from Active Faults.......................................................................................................................................................................................... 27
Map 2-14. Ground Shaking Hazard Map of San Juan................................................................................................................................................................... 28
Map 2-15. Liquefaction Hazard Map of San Juan ......................................................................................................................................................................... 29
Map 2-16. Flood Hazard (10 RP) Map of San Juan ...................................................................................................................................................................... 30
Map 2-17. Flood Hazard (50 RP) Map of San Juan ...................................................................................................................................................................... 31
Map 2-18. Flood Hazard (200 RP) Map of San Juan .................................................................................................................................................................... 32
Map 2-19. Flood Susceptibility Map of San Juan .......................................................................................................................................................................... 33
Map 2-20. Landslide Susceptibility Map of San Juan.................................................................................................................................................................... 34
Map 2-21. Severe Wind Hazard (20 RP) Map of San Juan........................................................................................................................................................... 35
Map 2-22. Severe Wind Hazard (100 RP) Map of San Juan......................................................................................................................................................... 36
Map 2-23. Severe Wind Hazard (200 RP) Map of San Juan......................................................................................................................................................... 37
Map 4-1. Educational Facilities Map ........................................................................................................................................................................................... 55
Map 4-2. Health Facilities Map.................................................................................................................................................................................................... 58
Map 4-3. Social Welfare Facilities Map....................................................................................................................................................................................... 74
Map 4-4. Protection Services Map.............................................................................................................................................................................................. 78
Map 4-5. Recreational Facilities Map.......................................................................................................................................................................................... 88
Map 5-1. Cultural Facilities Map................................................................................................................................................................................................ 102
Map 6-1. Road Network Map of San Juan ................................................................................................................................................................................ 117
Map 6-2. San Juan City Drainage Map ..................................................................................................................................................................................... 142
Map 6-3. Cell Sites and Postal Services Map (2012) ................................................................................................................................................................ 148
Map 7-1. Population Exposure Map - Flood Hazard.................................................................................................................................................................. 157
Map 7-2. Population Exposure Map – Rain-induced Landslide ................................................................................................................................................. 158
Map 7-3. Population Exposure Map – Liquefaction................................................................................................................................................................... 159
Map 7-4. Critical Facilities Exposure Map - Flood Hazard......................................................................................................................................................... 166
Map 7-5. Critical Facilities Exposure Map – Rain-induced Landslide ........................................................................................................................................ 167
Map 7-6. Critical Facilities Exposure Map – Liquefaction .......................................................................................................................................................... 168
14. xiii || CITY OF SAN JUAN
List of Abbreviations
AHYD Adolescent Health and Youth Development
AEP annual exceedance probability
APGR annual population growth rate
ASL above sea level
AUSAID Australian Aid
BDRRMC Barangay Disaster Risk Reduction and Management
Council
BHC Barangay Health Center
BHS Barangay Health Stations
BIDs Business Development Districts
BOC Barangay Operations Center
BOD Biochemical Oxygen Demand
BPOs business process outsourcing
BSWM Bureau of Soils and Water Management
CBMS Community-Based Monitoring System
CBD central business districts
CBR crude birth rate
CDR crude death rate
CDRRMO City Disaster Risk Reduction and Management Office
CEDOC-ERN City Central Emergency and Disaster Operations
Center - Early Response Network
CESU City Epidemiology and Surveillance Unit
CICL Children in conflict with the law
COD Chemical Oxygen Demand
CLIRAM Climate Information Risk Analysis Matrix
COMELEC Commission on Elections
CPDO City Planning and Development Office
DFAT Department of Foreign Affairs and Trade – Australia
DILG Department of Interior and Local Government
DOF-BLGF Department of Finance - Bureau of Local Government
Finance
DOTr Department of Transportation
DPWH Department of Public Works and Highways
DREAM University of the Philippines Disaster Risk and
Exposure Assessment for Mitigation
DRRMO Disaster Risk Reduction and Management Office
ENG City Engineering Office
EOC Emergency Operations Center
e-SRE Statements of Receipts and Expenditures report
GAD gender and development
GIS geographic information system mapping
GMMA READY Enhancing Greater Metro Manila’s Institutional
Capacities for Effective Disaster / Climate Risk
Management towards Sustainable Development
Project
GSD General Services Division
HLURB Housing and Land Use Regulatory Board
IEC information, education, and communication
IMR infant mortality rate
ISF informal settlement families
IPCC Intergovernmental Panel on Climate Change
JICA Japan International Cooperation Agency
LDRRMP Local Disaster Risk Reduction and Management Plan
LGUs Local Government Units
LMU Land Management Unit
LPG Liquified Petroleum Gas
LTFRB Land Transportation Franchising and Regulatory
Board
MASL meters above sea level
MERALCO Manila Electric Company
MGB Mines and Geosciences Bureau
MMDA Metropolitan Manila Development Authority
MMEIRS Earthquake Impact Reduction Study for Metropolitan
Manila
MMR maternal mortality rate
MWCI Manila Water Company Inc.
15. ECOLOGICAL PROFILE 2021 || xiv
MWSS Metropolitan Waterworks and Sewerage System
NCR National Capital Region
ORP oxidation-reduction potential
PAGASA Philippine Atmospheric, Geophysical and
Astronomical Services Administration
PCO Police Commissioned Officers
PCP Police Community Precinct
PHIVOLCS Philippine Institute of Volcanology and Seismology
PID Public Information Department
PIMC Population Information and Monitoring Committee
PM10 particulate matter 10
PNCO Police Non-commissioned Officers
POSO Public Order and Safety Office
PSA Philippine Statistics Authority
PMR proportioned mortality rate
PUP Polytechnic University of the Philippines
RAP risk analysis project
RCP representative concentration pathway
RHU Rural Health Units
SPED special education classes
SRU Special Reaction Unit Office
TFR total fertility rate
TSP total suspended particulates
TPMO Traffic and Parking Management Office
TRB Tricycle Regulatory Board
UNDP United Nations Development Program
UNDRR United Nations Office for Disaster Risk Reduction
WACS Waste Analysis and Characterization Study
WQMA Water Quality Management Areas
YCMR young child mortality rate
16. 1 || CITY OF SAN JUAN
CHAPTER 1. HISTORY
During the pre-Hispanic period, the village of what is now San Juan was a
part of the Kingdom of Namayan, whose last recorded rulers were King
Lacantagean and his wife Bouan. When the Spanish first took over the
kingdom which they re-christened as Sta. Ana de Sapa, the village remained
a part of it, re-classified as a barrio, and became a small encomienda by
1590. In 1602, the Dominican friars built a retreat house for their immediate
use, where aging or convalescing friars stayed. Later, the Dominicans
constructed a convent and a stone church dedicated to the Holy Cross. To
this day, the thrice-rebuilt church of Santo Cristo stands on the same site,
adjacent to the Aquinas School and the Dominican College. In 1783, San
Juan became independent of Santa Ana but it was still then a barrio.
The first battle of the Philippine Revolution that achieved independence from
Spain began in San Juan in 1898.
"San Juan" is a contraction of the city's longer official name: San Juan del
Monte (English: "St. John of the Mountain"). It is named in honor of St. John
the Baptist, the city's patron saint, and the hilly terrain the city is situated on.
On June 16, 2007, voters in San Juan ratified the conversion of the
municipality into a highly urbanized city, pursuant to Republic Act No. 9388
("An Act Converting the Municipality of San Juan into a Highly Urbanized City
to be known as the City of San Juan"). Then Rep. Ronaldo B. Zamora
sponsored the Cityhood Bill at the House of Representatives and worked for
its approval.
17. ECOLOGICAL PROFILE 2021 || 2
CHAPTER 2. GEO-PHYSICAL ENVIRONMENT
2.1. Geographical Location
The City of San Juan is located in the central geographic area of the National
Capital Region (NCR) known as Metropolitan Manila, with coordinates 12° 36'
N, 121° 02' E. The city is approximately 5 kilometers from Quezon City and
5.4 kilometers from the City of Manila. It is approximately 5.4 kilometers from
the Central Business Districts (CBD) of Makati, 4 kilometers from the Ortigas
CBD, and 6.4 kilometers from the Taguig CBD. The Location Map is
presented in Map 2-1.
2.2. Political Boundaries and Land Area
The City of San Juan is bounded on the north by Quezon City; on the west by
the City of Manila; and bounded on the south and east by the City of
Mandaluyong, as shown in Map 2-2.
In terms of land area, San Juan is the smallest city in Metro Manila with less
than 1% share of the total land area based on PSA data.
Table 2-1 shows a comparison of the land areas of Metro Manila cities and
municipalities.
Table 2-1. Comparison of Land Areas of the Cities and Municipalities of
Metro Manila
Region and City / Municipality
Land Area
(sq. km.)
% share
National Capital Region (NCR) 619.54
City of Manila 24.98 4.03%
Quezon City 171.71 27.72%
City of Caloocan 55.80 9.01%
City of Las Piñas 32.69 5.28%
City of Makati 21.57 3.48%
City of Malabon 15.71 2.54%
City of Mandaluyong 9.29 1.50%
City of Marikina 21.52 3.47%
City of Muntinlupa 39.75 6.42%
City of Navotas 8.94 1.44%
City of Parañaque 46.57 7.52%
City of Pasay 13.97 2.25%
City of Pasig 48.46 7.82%
Municipality of Pateros 10.40 1.68%
City of San Juan 5.95 0.96%
City of Taguig 45.21 7.30%
City of Valenzuela 47.02 7.59%
Source: PSA 2015
18. 3 || CITY OF SAN JUAN
San Juan is composed of 21 barangays, divided into two (2) districts (See
Map 2-3). As presented in Table 2-2, District 2 covers almost 70% of the total
area of the city with the largest share coming from Barangay Greenhills with
34.98% or 207.86 hectares. The three (3) smallest barangays are Progreso
(4.10 hectares), St. Joseph (3.81 hectares), and Isabelita (3.44 hectares).
Table 2-2. Land Area per Barangay
Barangay
Land Area
(ha)
% Share
District 1 191.33 32.20%
Balong-Bato 24.55 4.13%
Batis 38.89 6.54%
Corazon De Jesus 33.80 5.69%
Ermitaño 10.86 1.83%
Pasadeña 24.90 4.19%
Pedro Cruz 18.77 3.16%
Progreso 5.33 0.90%
Rivera 7.36 1.24%
Salapan 18.62 3.13%
San Perfecto 8.25 1.39%
District 2 402.90 67.80%
Addition Hills 37.06 6.24%
Greenhills 193.40 32.55%
St. Joseph 2.88 0.48%
Isabelita 18.76 3.16%
Kabayanan 45.46 7.65%
Little Baguio 20.90 3.52%
Maytunas 193.40 32.55%
Onse 2.88 0.48%
Santa Lucia 32.34 5.44%
Tibagan 17.99 3.03%
West Crame 20.24 3.41%
TOTAL AREA 594.23 100.00%
22. 7 || CITY OF SAN JUAN
2.3. Topography
Among the three geomorphologic categories of Metro Manila, San Juan is
found in the Central Plateau which is identified for its stiff soils and elevations
ranging from 20 meters above sea level (ASL) to 40 meters ASL, to 70
meters ASL to 100 meters ASL (PHIVOLCS in MMEIRS 2004).
2.3.1. Elevation
San Juan's elevation ranges from two meters ASL to 43 meters ASL while
most areas are within 15 meters to 25 meters ASL. The highest area is found
in Barangay Greenhills along the easternmost boundary of San Juan peaking
at 43 meters ASL then gradually decreasing in elevation towards Ermitaño
Creek in the central areas. Elevation in the western half of San Juan peaks at
26 meters ASL at Barangay Corazon de Jesus, where the Pinaglabanan
Shrine is located and gradually decreases in elevation towards the
surrounding river and creeks. Portions of Little Baguio, Sta. Lucia, and
Addition Hills also have relatively high elevations. The elevation distribution
based on is presented in Table 2-3 below and depicted in Map 2-4.
Table 2-3. Elevation Area Tabulation
Elevation (MASL) Area (ha) %
0 - 5 88.89 14.96%
5 - 10 86.85 14.62%
10 - 15 79.11 13.31%
15 - 20 120.30 20.24%
20 - 25 115.12 19.37%
25 - 30 57.05 9.60%
30 - 35 31.49 5.30%
35 - 40 9.63 1.62%
40 - 45 5.79 0.97%
Source: NAMRIA Topographic Map
2.3.2. Slope
Based on University of the Philippines Disaster Risk and Exposure
Assessment for Mitigation (DREAM) Program Light Detection and Ranging
(LiDAR) data, San Juan has a slope gradient ranging from level to hilly,
although it is mostly level to very gently sloping, as shown in the slope
distribution table in Table 2-4 and in Map 2-5.
Table 2-4. Slope Distribution in San Juan
Slope (%) Description Area (ha) %
0 - 3 Level to Very Gently Sloping 371.93 62.59%
3 - 8 Gently Sloping to Undulating 193.92 32.63%
8 - 18 Undulating to Rolling 28.03 4.72%
18 - 30 Rolling to Hilly 0.36 0.06%
Total 594.23 100.00%
2.4. Geology
San Juan is underlain by geologic features that was formed as early as the
Pliocene-Pleistocene Period, as shown in Map 2-6 Additionally, the majority
of San Juan is composed of tuff and tuffaceous sediment while some
northeastern areas are composed of pyroclastic flow adobe deposit.
These soils are volcanic in nature. Reworked deposits of volcanic tuffs are
present around Metro Manila and are sifted into three (3) types. The first tuff
layer is well lithified, fine-grained, with presence of dark prismatic minerals
and pumice. The second tuff layer is of a finer grain mostly made up of
volcanic ash. The third tuff is coarser, made up of volcanic breccia or
pyroclastic flow deposit. Pyroclastic flow deposit is a type of volcanic rock,
two of which are found underlying Metro Manila, the mixed scoria- pumice
flow and the fine-grained pumice-rich pyroclastic flow. The latter is however
more dominant. All these are associated with past volcanic eruptions from the
nearby Taal volcano (MMEIRS, 2004)
23. ECOLOGICAL PROFILE 2021 || 8
Generally, volcanic soils have more capacity to hold water and may cause
areas to be prone to liquefaction.
2.4.1. Soils
The city is identified with having Novaliches clay loam adobe. Soils under
Novaliches Series are characterized by clay loam/loam surface soil types with
high water retention and moderate drainage, permeability, and
workability/tilth. Stoniness is defined by irregular gravels and partially
weathered tuffaceous rock fragments; hence erosion is slight to moderate. In
terms of soil fertility, it is slightly acidy (5.0-6.0), low in organic matter, high in
phosphorus, low to moderate potassium, moderate to high nutrient retention,
high base saturation, and low salinity hazard. This type of soil is in the
incipient development towards a mature soil Inceptisol formed from older
alluvial deposits. It has a mean annual soil temperature higher than 22°C
isohyperthermic. The Soil Map is presented in Map 2-7.
2.4.2. Land Capability Classes
The Bureau of Soils and Water Management (BSWM) determines the Land
Capability using the Land Management Unit (LMU) approach. Land Capability
is the inherent capacity of land to perform under a given use and sustain a
desirable combination of plants and animals. The LMU is a delineation of a
recurring pattern of similar landform and material with relatively homogenous
soil characteristics, qualities and land use/vegetation which serves as a basis
for resource information and suitability to different land uses. This shows that
the City of San Juan is typically suited for non-agricultural use.
28. 13 || CITY OF SAN JUAN
2.5. Land Resources
2.5.1. Land Classification
In terms of land classification, the City of San Juan is categorized under
alienable and disposable lands. Alienable and disposable lands refer to those
lands of the public domain which have been the subject of the present system
of classification and declared as not needed for forest purposes.
2.5.2. Land Cover
Land cover is the observed (bio)physical cover on the earth's surface. Based
on the 2010 Land Cover data of NAMRIA, San Juan falls under built-up
category.
2.5.3. Existing General Land use
San Juan covers a land area of 5.94 sq. km (594.23 hectares), which is
0.97% of Metro Manila's 615.02 sq. km total land area. It is one of the
smallest local government units (LGUs) in Metro Manila, second to the
Municipality of Pateros. The largest is Quezon City which is adjacent to San
Juan in the north.
A land use mapping activity was conducted in February 2021 to determine
the actual land uses in the City of San Juan. These land uses were
determined through field surveys, GPS mapping, and aerial photo
interpretation shown in Map 2-8 (subject to review and TWG Validation).
Table 2-5 presents a comparison of the land uses for the years 2013 and
2020. The following were some of the observations and findings of the
mapping activity:
i. Cemetery Uses – Cemetery uses account for less than 1% of the total
land area of San Juan. This use can be found in West Crame. No
significant changes have been observed for this land use category.
ii. Commercial Uses – About 11.32% of the total lands of the city are
allocated for commercial land uses, mostly in Barangay Greenhills.
Based on the land use map, it can be observed that these type of land
uses are located along main roads traversing the city. These include
major commercial establishments such as banks, food
establishments, office buildings, convenience stores, wet and dry
markets, and major trade and retail business centers.
iii. Vacant lands – The land use matrix shows a decrease in the vacant
lands in the city. However, it should be noted that a more
comprehensive inventory of these types be continuously monitored
and validated.
iv. Industrial – An estimated 8.02 hectares of industrial land uses can be
found in the western part of the city bordering the San Juan River.
These are usually storage warehouses.
v. Informal Settlements – About 4.30 hectares or 0.72% of the lands of
San Juan are identified as informal settlements.
vi. Institutional Uses – Institutional uses take up 7.18% (or 42.69
hectares) of the total land area. These include the city hall, barangay
halls, health centers, protective services, schools, social welfare
facilities, religious establishments, and other government offices and
structures.
vii. Parks / Open Spaces – The observed increase in parks/open spaces
from 2013 to 2020 can be attributed to the San Juan Coliseum and
areas surrounding the Pinaglabanan Shrine which was tagged as
recreational spaces. This type of spaces function as the lungs of the
city while serving as areas for civic and social activities.
29. ECOLOGICAL PROFILE 2021 || 14
viii. Residential Uses – This type of land use has the largest share of total
land allocation in the city. An estimated 369.97 hectares or 62.26% of
the lands are mapped as residential lands, depicted by presence of
exclusive subdivisions or gated communities. This also includes
socialized housing uses in the city.
ix. Rivers and Waterways – While there is an observed decrease, it
should be noted that lack open data for river tributaries would require
additional mapping efforts for database development.
x. Roads – Road uses cover 13.28% of the total lands of San Juan. This
type has the second largest share of uses in the city. As observed in
the land use map, barangays and establishments are linked through
an extensive road network in grid-type patterns.
xi. Utilities – Transport terminals make up this type of land use.
Table 2-5. Land Uses in San Juan, 2013 and 2020
Land Use Category
Existing Land Use
(2013)
Existing Land Use
(2020)
Area (ha) % share Areaa
(ha) % share
Cemetery 2.77 0.47% 2.75 0.46%
Commercial 67.09 11.29% 68.40 11.51%
Vacant lands 6.84 1.15% 0.59 0.10%
Industrial - 0.00% 8.04 1.35%
Informal Settlements - 0.00% 3.80 0.64%
Institutional 40.93 6.89% 42.24 7.11%
Parks/Open Spaces** 1.12 0.19% 9.66 1.63%
Residential 364.55 61.35% 367.94 61.92%
Rivers and Waterways 16.24 2.73% 9.20 1.55%
Roads
94.69 15.93%
79.16 13.32%
Utilities 2.43 0.41%
TOTAL 594.23 100.00% 594.23 100.00%
a - GIS-derived computation, adjusted based on land area
2.5.4. Land Use Trends and Pattern
In the years that followed the formulation of the Comprehensive Land Use
Plan in 2013 up to the present state, the city grew in similarly to what was
projected under the CLUP. The projected change was expected as
development in the city is limited due to lack of space; hence, the trends in
San Juan are towards higher densities or vertical development.
In the existing plan of the city, the major growth and development area is in
the eastern part, specifically in the areas of Barangay Greenhills. This
commercial land uses have reinforced mixed uses through an observed linear
type of development along roads and streets. Aside from commercial uses,
strong institutional centers are also strategically located in the city and
ongoing upgrading of the city’s social infrastructure are also evident. While
the city’s structure is predominantly residential given the large lands allocated
to gated communities, there are lots allocated for in-city relocation/socialized
housing projects. Still, informal settlement families (ISF) are also typically
found in areas adjacent to waterways. Tracts of idle lands can also be
observed in some areas of the city, while there is an increase in support on
urban greening.
Industrial factories in the northwestern part along the San Juan River have
already started closing, relocating, or scaling down operations, although the
area is still yet to be re-developed for the planned waterfront development.
Being strategically located in the heart of the metro, its extensive road
network, transport utilities, and dedicated bike lanes make San Juan easily
accessible and safe for commuters.
30. 15 || CITY OF SAN JUAN
Map 2-8. Satellite Image of San Juan
32. 17 || CITY OF SAN JUAN
2.6. Water Resources
2.6.1. Surface Waters
Surface water within a city is not only about the water that is within its
boundaries. It is affected by upstream activities and activities within the city
boundaries. To achieve a more complete understanding of the waters within
the City of San Juan, its connecting rivers and creeks must also be
considered.
The main water body of San Juan City is the San Juan River, one of the
major tributaries of Pasig River. The river flows from north to south and is
connected to the San Francisco River which originates from M.H. Del Pilar St.
in Quezon City. The San Juan River passes through San Juan, Manila,
Quezon City, and Mandaluyong before draining into the Pasig River. A map
of the San Juan River Basin is presented in Map 2-10.
The total catchment area of the San Juan River basin is 90.4 sq.km,
consisting of the lower half of Quezon City, the City of San Juan and parts of
Mandaluyong City, Pasig City, and the City of Manila. Meanwhile, barangays
traversed by the San Francisco River are presented in Table 2-6. The total
length of San Francisco-San Juan River is approximately 10.57 km with an
average width of 37.4 m.
Table 2-6. Estimated Lengths of San Francisco-San Juan River
Segment Length (km)
San Francisco River (M.H. Del Pilar - Mouth of Maribolo Creek) 3.15
San Juan River Maribolo Creek - Diliman Creek 1.13
Diliman Creek - Ermitano Creek 2.53
Ermitano Creek - Maytunas Creek 2.04
Maytunas Creek - Unknown Creek 0.88
Unknown Creek - Pasig River 0.84
Total length 10.57
Source: DENR-EMB, 2012, CLUP 2013-2023
San Juan River’s tributaries include Ermitaño Creek and Maytunas Creek,
approximately 4.9 km and 1.4 km long respectively. Ermitaño Creek runs
along the northern boundaries of Barangays Salapan, Ermitaño, and
Pasadena, continuing along the eastern boundaries of Barangays Pasadena,
Little Baguio, and Addition Hills, stretching to Mandaluyong City. Maytunas
Creek, on the other hand, runs along the southern borders of Barangay
Addition Hills, Sta. Lucia, Maytunas, and Kabayanan.
2.6.2. Natural Drainage Pattern
The flow of water generally trails from east to west, carried by creeks and
then flows southward through the San Juan River. The greatest bulk of runoff
will come from Ermitaño Creek which drains water to more than half of
northern and eastern San Juan. The remaining areas are roughly equally
divided between San Juan River and Maytunas Creek.
2.6.3. Groundwater Sources
The delineated surface water catchments contributing groundwater to the
Metro Manila aquifer constitute an individual aquifer system where their
groundwater discharges into Manila Bay and before reaching the sea,
merging to form a complex type of aquifer system. The extent of the
groundwater basin is delineated based on the surface water divides (NWRB,
2004). A map is presented in Map 2-11.
2.6.4. Water Quality Management Area
Section 5 of RA 9275 or the Philippine Clean Water Act of 2004 tasked the
DENR in coordination with the National Water Resources Board to designate
certain areas as water quality management areas (WQMA) using appropriate
physiographic units such as watershed, river basins or water resources
regions.
33. ECOLOGICAL PROFILE 2021 || 18
The objective of the WQMA is to protect, through stakeholders’ collaboration,
the water body and its tributaries by keeping their water quality within the
Water Quality Guidelines or Criteria conforming to the water body’s
classification (e.g., Class C or Class SC) or even improve the quality to
higher classification (e.g., from C to B or SC to SB). As of August 1, 2018,
there are thirty-seven (37) officially- designated WQMAs. Classification
means the categorization of all water bodies considering the existing quality
of the body of water and most beneficial existing and future use of said
bodies of water and lands bordering them, such as for residential,
agricultural, aquacultural, commercial, industrial, navigational, recreational,
wildlife conservation and aesthetic purposes, among others.
The San Juan River System was designated as a Class C WQMA by the
DENR through DAO 2021-04. Class C WQMAs are intended for fish
propagation and growth, recreational use for secondary contact sports such
as boating, and after treatment, for industrial water supply for manufacturing
processes and other aquatic resources. However, its actual condition is far
from the intended use.
34. 19 || CITY OF SAN JUAN
Map 2-10. Hydrology Map 2-11. Groundwater Potential
35. ECOLOGICAL PROFILE 2021 || 20
2.7. Climate
The City of San Juan falls under the Type I classification of the Modified
Climate Corona Classification, like any other areas in the western part of
Luzon, Mindoro, Negros and Palawan. This type of climate is characterized
by two pronounced seasons: dry from November to April and wet the rest of
the year. Climate Map is shown in Map 2-12.
2.7.1. Atmospheric Temperature
Based on the 1981-2010 climatological normals of Science Garden Synoptic
Station, its annual mean temperature is 27.7°C. January is the coolest month
with an annual mean temperature of 25.7°C while the warmest month is May
with an annual mean temperature of 29.7°C. Minimum temperature is
observed on the month of January at 20.8°C on the average, while the
maximum temperature is observed on the month of April at 35.0°C on the
average.
2.7.2. Relative Humidity
Humidity refers to the moisture content of the atmosphere. Relative humidity
in Science Garden varies with the seasons. The most humid months are the
months of June to December with 79-84% relative humidity, while the dry
months of January to April being the least humid with relative humidity values
of 67-76%. The annual mean relative humidity in the area is 78%.
2.7.3. Rainfall
Rainfall is the most important climatic element in the Philippines. Rainfall
distribution throughout the country varies from one region to another,
depending upon the direction of the moisture-bearing winds and the location
of the mountain systems. Data from Science Garden, as basis for San Juan
City, receives an average annual rainfall of 2574.4 millimeters as of 1981-
2010 annual climatological normals. The wettest months are June to October
which coincides with the southwest monsoon, while the months of January,
February, March and April are the driest with monthly averages of 18.5 mm,
14.6 mm, 24.8 mm and 40.4 mm respectively.
2.7.4. Prevailing Winds
The Philippines is located in the tropics and the weather and climate
prevailing in any particular place in the country is due to its geographical
location and the different wind systems that prevail in the locality during the
different times of the year. On the average, the prevailing wind in the
Philippines from October to February is northeasterly (coming from the
northeast, or amihan), easterly from March to May due to the Pacific trade
winds, and southwesterly (habagat) from June to September.
Weather patterns in the Philippines are dictated by the prevailing winds – the
habagat (southwest monsoon) and the amihan (northeast monsoon). The
southwest monsoon brings heavy rains to places with Type I climate from
May to October.
2.7.5. Tropical Cyclone
From 1948 to 2013, an average of 20 tropical cyclones have crossed Metro
Manila - 13 of these TC’s reached typhoon category, 5 are tropical storms
and 2 tropical depressions. Tropical cyclone occurrence in the city is most
expected during the second half of the year which partly explains the rains
during this period.
These weather systems spare the city however during the months of January
to April. 65% of tropical cyclone directly crossing Metro Manila is of typhoon
intensity while 25% is tropical storm and 10% is depression. This exposes the
Metro Manila area including San Juan City with the adverse impacts of
associated with the passage of tropical cyclone.
36. 21 || CITY OF SAN JUAN
Map 2-12. Climate Map of San Juan
37. ECOLOGICAL PROFILE 2021 || 22
2.7.6. Climate Change Projections
In 2018, the Philippine Atmospheric, Geophysical and Astronomical Services
Administration (PAGASA) released a study on the projected seasonal
temperature increase and seasonal rainfall change for the mid-21st century
(2036-2065). The climate projections utilized Climate Information Risk
Analysis Matrix (CLIRAM). It also considered Representative Concentration
Pathway (RCP) 4.5 or the moderate emission scenario which is described by
the Intergovernmental Panel on Climate Change (IPCC) as an intermediate
scenario. Emissions in RCP 4.5 peak around 2040, then decline. RCP 8.5 or
the high emission scenario was already presented in the report, which is
generally taken as the basis for worst-case climate change scenarios.
Based on the observed baseline data from 1971 to 2000, the study revealed
warmer condition which could range from 1.0°C-1.8°C (based on moderate
emission scenario) to 1.2°C-2.3°C (based on high emission scenario)
increase in mean temperature relative to the baseline climate data. This
projected scenario indicates warmer temperatures all throughout the year,
especially for the months of March, April and May or summer. Table 2-7
presents the projected seasonal change in mean temperature and projected
value based on moderate and high emission scenario.
Table 2-8 presents the seasonal rainfall change which indicates a significant
decrease in rainfall amount from June to August, and an increase in projected
rainfall for the months of December to February.
Furthermore, the projections also reveal that sea level in the country is
expected to increase by approximately 20 cm by the end of the 21st century
under RCP8.5 scenario (PAGASA, 2018).
2.7.7. Climate Change Impacts
2.7.7.1. Extreme Rainfall
Future changes in rainfall indicate a wetter wet season for San Juan.
Increases in rainfall is evident during the wet season which coincides with the
monsoon season which may lead increasing likelihood of flooding especially
in low-lying areas. This could potentially exacerbate flood extent and severity.
Immediate primary impacts include submerged roads/streets, social
infrastructure facilities and houses, leading to disruption of movement,
potential isolation of communities, and damage to structures. Such impacts
would entail significant government resources to be allocated for relief and
rehabilitation projects. Flooding also increases risks to water-borne diseases.
Aside from flooding, increase in rainfall with higher severity of occurrence
could also trigger climate-related hazards such as soil erosion and rain-
induced landslide in the northeastern part of the city.
2.7.7.2. Temperature Changes
Another climate-related stimulus is increase in temperature which could
intensify impacts of typhoons. Such changes also lead to urban heat island
effect which raises temperatures in highly urbanized areas. This causes
increased Energy Consumption; elevated emissions of air pollutants and
greenhouse gases; compromised human health and comfort; and impaired
water quality.
