1.6 ENVIRONMENTAL MANAGEMENT

Transcription

1 1.6 ENVIRONMENTAL MANAGEMENT The public is reminded of the necessity of adjusting human activity to the processes of nature each time an extreme natural event such as a flash flood, typhoon or earthquake occurs. These occurrences pose a threat to life and property and the risk is significant in the City -- one of the most important business centers in the country. Environmental degradation also raises the hazards associated with living in the City. Man-made pollution continues to be a major cause of respiratory diseases while also contributing to the rise in global temperatures that are associated with the extreme weather events experienced in different parts of the world. Earthquakes are part of a natural process and the damage it causes to urbanized areas affects decisions made on where and how to build. Whether these are houses, roads, skyscrapers, malls or any other structure needed for habitation or commerce, the structural system must fit the type of underlying material on which it rests. Man-made pollution in its various forms, on the other hand, are brought about by activities of the resident population, its larger transient (daytime) population and the resulting vehicular traffic generated by the convergence of residents, workers and pass-by commuters. Due to the interconnectedness of Makati and adjacent cities, addressing and mitigating risk from natural geologic and climatic events and human activity requires a metropolitan or even national approach. Problems regarding air quality, water pollution, and waste management, for instance, need integration and coordination with efforts at a regional scale. Local efforts, are likewise essential and will go a long way towards reducing environmental degradation and the impacts of natural disasters. The natural physical characteristics of the City and the changes it undergoes over time exert pressure on the City to be prepared for extreme scenarios. Natural movements of the earth s crust and extreme weather occurrences present hazards that can lead to damage to property, injury and even loss of lives. The threat posed by these processes if ignored increases the potential damage that may result in the aftermath of such events. A deeper understanding of the physical characteristics and natural processes and identification of the critical areas that are most likely to be affected are essential steps towards a plan of action for mitigating the associated risks of natural events and human activity Geology Tectonic Setting The identification and understanding of geologic structures is essential in planning and development as man-made structures may significantly affect the stability of underlying rock units. The type of underlying rock will determine the need for and/or appropriate design of building foundations to prevent or mitigate the effects ground movement or differential settlement. Based on the regional

2 geology, several tectonic features and structures (Figure 11), might affect Makati City, namely: (1) The West Valley Fault (WVF) of the Valley Fault System (VFS), formerly known as the Marikina Valley Fault System (MVFS). The VFS is essentially a gravity fault system consisting of two (2) parallel northeast trending faults, the West Valley Fault (WVF) and the East Valley Fault (EVF). (2) The Philippine Fault (PF) which is an active left lateral strike slip fault and traverses the archipelago from northern Luzon to southern Mindanao with a general trend of northwest-southeast (MGB, 2003). (3) The Casiguran Fault, which was identified by Daligdig and Besana (1993) as one of the potential earthquake generators that may affect the metropolis and nearby provinces. (4) The Lubang Fault, which is a strike slip west-northwest trending fault. It is mapped between Batangas and Mindoro (Daligdig and Besana, 1993). (5) The Philippine Trench, where the Philippine Sea Plate (PSP) subducts beneath the eastern Philippine Archipelago. Subduction of the PSP produces potentially destructive earthquakes (MGB, 2003). (6) The Manila Trench, where the South China Sea subducts beneath the western Philippines. Numerous earthquakes have been attributed to the movement along this trench (MGB, 2003). Figure 11. Major tectonic elements that may affect Makati City. Source: Distribution of Active Faults and Trenches in the Philippines, Philippine Institute of Geology and Seismology; Galgana, G., et. al, 2007.

3 Stratigraphy and General Geology Based on the geological map of the Manila and Quezon City Quadrangle published by the Mines and Geosciences Bureau (MGB), majority of Makati City is underlain by the Diliman Tuff Member of the Pleistocene Guadalupe Formation (BMG-DENR, 1983). The Guadalupe Tuff Formation, which underlies most of Metro Manila, is a horizontally bedded rock commonly referred to as adobe. It consists of well-laid rock formation of tuffaceous sandstone, tuffaceous siltstone and shale being the weakest member. The geologic map of Mines and Geosciences Bureau (Sheet 3263-IV) described the Diliman Tuff to be made up of thin to medium bedded, fine-grained vitric tuffs and welded volcanic breccias with subordinate amount of tuffaceous, fine- to medium-grained sandstone." Structural Geology The nearest known active fault within the City is the West Valley Fault (Figure 12). This north to northwest trending fault extends from the town of Rodriguez, Rizal, up north, transects parts of eastern Marikina, and can be traced as far south as Tagaytay Ridge. Rimando, et al. (1996) documented the presence of ground ruptures with vertical and/or horizontal displacements situated in the Muntinlupa-San Pedro-Biñan area. He concluded that the systematic distribution and consistency of these ruptures with the master faults of the WVF were caused by the creeping movements along the WVF. Graduate students from the National Institute of Geological Sciences (NIGS) were able to delineate north-northeast trending fractures when they mapped the Ortigas-Pasig area (Anacio, 2000). These vertical displacements were attributed to the WVF. Figure 12. Regional Geologic Map, Cross-section and Stratigraphy of the Study Area Source: Geologic Map of Manila and Quezon City Quadrangle. Sheet 3263-IV. BMG-DENR, 1983.

4 1.6.2 Geologic Hazard This assessment aimed to evaluate the geological environment of the area and to determine if there are possible geological hazards that could affect the different parts of the City. Tectonic Earthquakes Makati lies within a tectonically active region in the Philippines known as the Philippine Mobile Belt, and has experienced numerous destructive earthquakes in its recorded history. There are six (6) known tectonic earthquake generators affecting the area, namely (MGB, 2003 and Daligdig and Besana, 1993): (1) the Valley Fault System, (2) the Philippine Fault Zone, (3) the Lubang Fault, (4) the Casiguran Fault, (5) the Philippine Trench, and the (6) Manila Trench. The nearest active fault within the City is the West Valley Fault. Ground Acceleration and Resonance Makati s response to movements along the WVF is calculated based on the seismic activity attributed to the nearest earthquake generator as identified by PHIVOLCS and the type of material underneath the project site. Daligdig and Besana (1993) produced a deterministic PGA (Possible Ground Acceleration) distribution map of Metro Manila from a magnitude 7.5 earthquake generated from the Valley Fault System. It is estimated that alluvial deposits will have a ground acceleration of 0.60 to 0.80 g while rocks in the Guadalupe formation will have 0.20 to 0.60 g from a 7.5 magnitude earthquake generated by the Valley Fault system in Pasig City. PGA values for the City ranges from in areas underlain by the Guadalupe Tuff in the central portion and in areas underlain by Quaternary Alluvium adjacent to the floodplains of Pateros River and flat areas to the west near Manila Bay.

5 Volume 1: Part 1 - Profile of Makati City Figure 13. Possible ground acceleration in the project site generated by the Valley Fault System (VFS). Source: Daligdig and Besana, Ground Rupture Surface rupture or the breaking and movement of the ground along the active fault trace could result to horizontal or vertical shifting of the ground or a combination of both. The official trace of the Marikina Valley Fault System can be seen on the eastern portion of Makati City. This fault system cuts across Barangays East Rembo, West Rembo, Comembo, Pembo and Rizal in District II. Figure 14. Trace of the Valley Fault within Makati City. Source: Philippine Institute of Volcanology and Seismology; Google Earth

6 Liquefaction and Differential Settlement Strong ground shaking caused by a high magnitude earthquake increases pore water pressures on the saturated subsurface causing the loose sand to expand. A subsurface made up of loose sand with the static water level near the ground level, is a typical subsurface susceptible to liquefaction. The result is to turn sand into a liquefied condition with an upward flow towards the surface which would consequently lead to differential settlement. Based on the PHIVOLCS Liquefaction Hazard Map, the potential for liquefaction in Makati ranges from low to none in areas underlain by the Guadalupe Tuff and moderate in areas underlain by Quaternary Alluvium. Areas of moderate hazard are mostly in District I, particularly, the west and northwestern region of Makati. These affect Barangays Kasilawan, Carmona, Singkamas, Tejeros, La Paz, San Antonio, Palanan and San Isidro and portions of Valenzuela, Olympia and Poblacion near the Pasig River. In District II, areas along the banks of Pateros River area also categorized as having moderate liquefaction hazard. The rest of Makati has low or no hazard due to liquefaction.

7 Figure 15. Liquefaction Hazards Map of Metro Manila Source: Philippine Institute of Volcanology and Seismology Mass Movement Makati is classified as having low susceptibility to landslide (Figure 16) according to a study done by Mines and Geosciences Bureau of DENR. However, mass movement may occur in areas with very steep and unprotected slopes produced by excavations and road cuts.

8 Figure 16. Landslide and Flood Susceptibility Map Source: Mines and Geosciences Bureau (MGB) and Department of Environmental and Natural Resources (DENR). Volcanic Hazards Out of the hundreds of recognized volcanoes in the Philippines, Twenty-three (23) are identified active by the Philippine Institute of Volcanology and Seismology (PHIVOLCS). Most active are Mt. Mayon, Taal, Bulusan, Canlaon and Hibok-hibok, the first three located in the island of Luzon (MGRP, 2004). Mt. Pinatubo, Mt. Banahaw and Taal Volcano are the active volcanic centers that are nearest to the city. Figure shows the distribution of the active volcanoes in the Philippines. Makati is classified as having no major risk to volcanic eruptions. However, due to the relative distance of these active volcanic centers from the City, ash fall deposits may be considered as one probable effect of an eruption from

9 surrounding volcanoes similar to what happened during the 1991 Pinatubo eruption. Figure 17. Map Showing the Distribution of Volcanoes in the Philippines Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

10 Flooding The existing flood hazard map of Makati from the Mines and Geosciences Bureau of DENR shows that the areas that are prone to 2- to 10-year flood cycles are distributed along creeks, Pasig River and low lying areas. On the other hand, parts of the City that are prone to 50- and 100-year flood cycle are restricted along the Pateros River and its junction with Pasig River. Figure 18. Flood Hazard Map of Metro Manila Note: Yellow areas are flood prone areas for 2- to 10-year flood cycle. Blue areas are flood prone areas for 50- and 100- year flood cycle. Source: Mines and Geosciences Bureau The watershed that contributes to Makati City has an area of km 2 and extends to the adjacent cities of Manila, Mandaluyong, Pasig, Taguig and Pasay. The topography of the watershed can be described as hilly to rolling terrain discharging into the Pasig River System, which eventually drains out to the Manila Bay. Flood prone areas for 2 to 10-year flood cycle include Barangays Kasilawan, Singkamas, Tejeros and Olympia on the northwest, areas near the banks of Pasig River, Barangays Bangkal and San Lorenzo, on the southwest and a small portion covering the southern portion of Barangay Bel-air and the northern portion of the MACEA-controlled area. Flood prone areas for 50-year and 100-year flood

11 cycle are mostly in the eastern portion of the City along Pateros River. Affected Barangays include West Rembo, East Rembo, Comembo, Pembo and Rizal. Figure 19. Makati Watershed

12 Simulations of Typhoon Ondoy was conducted using Flo-2D software. Flo-2D is a dynamic flood routing model that simulates channel flow, unconfined overland flow and street flow. The numerical simulation can track floods over complex topography and roughness while reporting on volume conservation; the key to accurate flood distribution. The model uses the full dynamic wave momentum equation and a central finite difference routing scheme with eight potential flow directions to predict the progression of a flood hydrograph over a system of square grid elements. The output maps include flood depth, flood velocity, and flood hazard. Figure 20. Results of the Flo-2D simulation for Makati City Flood occurrence is generally restricted to creeks and rivers except in western part of the City wherein sheet floods cover a large area due to the very low and flat topography. Flood depths in the western part ranges from 1-3 meters along the creeks and meter for residential adjacent to these creeks. On the eastern part of the city, flood depths ranges from 1-3 meters along the Pateros River and meter for a narrow area adjacent to the river. The deepest floodwaters are found along the Pasig River reaching above 6 meters. In the immediate vicinity of the Pasig River, flood depths ranges from meters.

13 1.6.3 Solid Waste Management Based on garbage collection data from the Solid Waste Management Division (SWMD) of the Department of Environmental Services (DES) for the period , the volume of actual garbage collected has generally been declining at an average rate of 2.03%. It was only in 2008 that there was a positive (0.5%) increase in garbage collected and disposed. The diversion rate of solid waste, on the other hand, has been increasing annually. Between 2006 and 2007, the diversion rate increased by 4.0%, the highest for the period. Makati has been able to comply with the mandatory diversion rate of 25% set in R.A for the whole 6-year period. In 2011, the City achieved a waste diversion rate of 44%, the highest ever, since monitoring started in Table 68. Comparative Volume of Garbage Collection Year Actual Garbage Collected and 886, , , , , ,747 Disposed (in cu. m.) Volume of Garbage Reduced (in cu. m.) 367, , , , , ,373 Target Rate (%) Diversion Rate Source: Department of Environmental Services Over 41,225 apprehensions have been made between 2006 and 2011 in relation to City Ordinance or the Makati Solid Waste Management Code. The number of violators, however, has generally decreased despite fluctuations as a result of increases in 2008 (22.82%) and in 2010 (28.39%). It was, however, only in 2008 that there was a corresponding increase from the previous year in garbage collected and disposed. The following year, 2009, there was a 48% decrease in apprehensions, despite having recorded the lowest number of cases for the 6-year period at 5,686. This however, did not affect the positive trend in volume reduction from 2009 onwards (Table 69). Table 69. Number of Apprehended Violators of Solid Waste Management Code Year No. of Apprehended 10, ,946 5,686 7,300 6,868 Violators % change % % 22.82% % 28.39% -5.92% Source: Department of Environmental Services

14 Aside from the enforcement of the Waste Management Code, three programs have been implemented with great success in order to achieve the positive results. These are the Weekend Waste Market, Baratilyo ng Basura sa Barangay and 3B sa Pasko program Water Quality Management Biochemical Oxygen Demand (BOD) value is one of the measures used to determine level of pollution in a body of water. A higher number indicates a higher concentration of organic pollutants. In 2005, the BOD level in the Pasig River measured from the Guadalupe water-monitoring station was mg/l. In the following year, this decreased to mg/l. The improvement, however, was not sustained as BOD levels increased annually by an average of 25% from 2007 to 2008 and then increasing more than threefold in 2009 to mg/l (the highest during the 5-year period). The goal for the Pasig River is to achieve the acceptable levels for class C inland waters, which are suitable for fishery, recreation and industrial water supply. The maximum acceptable BOD value for this level is 10 mg/l. Associated with water pollution is the presence of shanties along the river without sufficient sewage facilities and garbage disposal systems. Relocation efforts have been done in the past not only in Makati but also in other cities situated along Pasig River. There is, however, a need for all LGUs situated along the Pasig to make a concerted effort to achieve the desired level of water quality and sustain it in the future. Protection of easements from expansion of informal settlements and illegal structures and proper garbage disposal are some of the ways to bring BOD levels down to the desired level. Table 70. Biological Oxygen Demand, Guadalupe Monitoring Station Water Pollution Index Biological Oxygen Demand (BOD) mg/l mg/l mg/l 15.7 mg/l mg/l Source: Department of Environmental Services

15 1.6.5 Air Quality Management Based on the analysis of data from the Makati Pollution Control Office and DENR-EMB, the following can be said of the level of air pollution in Makati. TSP readings are monitored from the air quality monitoring station located along Ayala Avenue Extension corner Yakal Street in Brgy. San Antonio. Air quality recorded from 2006 to 2011 show that the highest TSP reading was registered in 2008 and 2010 at 158 ug/ncm and the lowest was recorded in 2009 at 106 ug/ncm. Significant drops were registered in 2006 (15.47%) and 2009 (32.91%). Despite this general improvement, the recorded figures exceed the long term standard for TSP of 90 ug/ncm. Table 71. Annual TSP Reading TSP Reading % change % -7.84% 12.06% % 49.06% 16.4% Source: DENR-EMB, 2010 The number of apprehended smoke belchers is fluctuating from 2006 to Apprehensions decreased by as much as 14% from the base data of 8,785 apprehensions in The highest decrease was recorded in 2011 at 21% Table 72. Apprehension of Smoke Belchers Number of apprehensions 7,520 6,461 6,662 6,704 6,595 5,214 % change % % 3.11% 0.63% -1.63% -21% Source: Makati Pollution Control Office, 2010 As the number of apprehensions went down from 2006 to 2007, TSP readings also went down suggesting a correlation between intensity of enforcement and TSP levels. The data shows that efforts against smoke-belching have attained some degree of success but still not enough to bring levels of TSP below the long-term-standard of 90ug/Ncm.

16 Number of Apprehensions Number of Apprehensions TSP (ug/cum) TSP ug/cum Figure 21. Number of Apprehended Smoke Belchers and Annual TSP Levels Based on a comparison of readings for periods May 2008 November 2009 and May 2009 October 2010, the monitoring station along Lawton Avenue in Barangay Cembo registered the highest PM10 readings. However, while 4 out of 5 stations recorded an increase in PM10 readings, only the Lawton Station recorded a decrease between the 2 periods (Table 73). Particulate matter in the City are mostly the result of the burning of fossil fuels and a factor of the volume of traffic the City generates as a financial center. To a certain degree commercial processes associated with its role as financial hub is also a contributing factor. Table 73. Summary of Collected Data on PM10, by Station and Period Covered PM10 Readings Station Pasong Tamo, Sta. Cruz A.P. Reyes, Carmona Kalayaan, Pitogo Lawton Ave., Cembo Comembo, JP Rizal Source: DENR-EMB, 2010 May2008 November 2009 May 2009 October 2010 % change % % % % %

17 1.6.6 Urban Greening One of the measures being undertaken by the City to arrest the rapid degradation of environmental quality brought about by industrialization and urbanization is through its urban greening program. This involves an integrated citywide green system to help reduce noise and air pollution, as well as provide for recreation and aesthetic enhancement to help improve the quality of life of the City s constituents. At present, there are 12 parks being monitored by the Parks and Green Division of the Department of Environmental Services with a total land area of approximately 8 hectares. The division also maintains four (4) plant nurseries for its tree planting activities. Since the tree planting activities started in 2002, 90,146 trees have been inventoried by the division giving a tree to person ratio of 1:7. This is still well below the standard tree to person ratio of 1:4 which at present is not met by the City due to the lack of space for greening. Table 74. Inventory of Parks Park Land Area (sq.m) Magallanes Interchange Park 25, 349 Buendia Plaza 3,316 Makati Park and Garden 35, 433 Poblacion Park 2,876 Kenken Lacia Binay Park 4,033 Guadalupe Viejo Park 1,484 Freedom Park 953 Pinagkaisahan Underpass Park 265 EDSA Buendia Park 1,022 Guadalupe Nuevo Linear Park 2,415 Valenzuela Linear Park 1,611 Makati DES Linear Park 3,672 Total 82,429 Source: Department of Environmental Services, 2010