Manila Bay

Manila Bay ( fil, Look ng Maynila) is a natural harbor that serves the Port of Manila (on Luzon), in the Philippines. Strategically located around the capital city of the Philippines, Manila Bay facilitated commerce and trade between the Philippines and its neighboring countries,Jacinto, G.S., Azanza, R.V., Velasquez, I.B. and Siringan, F.P.(2006)."Manila Bay:Environmental Challenges and Opportunities" in Wolanski, E.(ed.) The Environment in Asia Pacific Harbours. Springer: Dordrecht, Netherlands. p309-328. becoming the gateway for socio-economic development even prior to Spanish occupation. With an area of , and a coastline of , Manila Bay is situated in the western part of Luzon and is bounded by Cavite and Metro Manila on the east, Bulacan and Pampanga on the north, and Bataan on the west and northwest.Jacinto, G.S., Velasquez, I.B., San Diego-McGlone, M.L., Villanoy, C.L. and Siringan, F.B.(2006)."Biophysical Environment of Manila Bay - Then and Now", in Wolanski, E.(ed.)The Environment in Asia Pacific Harbours. Springer: Dordrecht, Netherlands. p. 293-307. Manila Bay drains approximately of watershed area, with the Pampanga River contributing about 49% of the freshwater influx. With an average depth of , it is estimated to have a total volume of 28.9 billion cubic meters (28.9 cubic km). Entrance to the bay is wide and expands to a width of . However, width of the bay varies from at its mouth and expanding to at its widest point.

The islands of Corregidor and Caballo divides the entrance into two channels, about towards the North and wide on the South side. Mariveles, in the province of Bataan, is an anchorage just inside the northern entrance and Sangley Point is the former location of Cavite Naval Base. On either side of the bay are volcanic peaks topped with tropical foliage: 40 km to the north is the Bataan Peninsula and to the south is the province of Cavite.

Across the entrance to Manila Bay are several islands, the largest of which is Corregidor, located 3 kilometers from Bataan and, along with the island of Caballo, separates the mouth of the bay into the North and South Channels. In the south channel is El Fraile Island and outside the entrance, and to the south, is Carabao Island. El Fraile, a rocky island some in area, supports the massive concrete and steel ruins of Fort Drum, an island fortress constructed by the United States Army to defend the southern entrance of the bay. To the immediate north and south are additional harbors, upon which both local and international ports are situated. Large number of ships at the North and South harbors facilitate maritime activities in the bay. Being smaller of the two harbors, the North Harbor is used for inter-island shipping while the South Harbor is used for large ocean-going vessels.

History

Manila Bay was connected to Laguna de Bay (pronounced "bai") approximately 3,000 years ago. Recurring episodic
uplifts along the West Marikina Valley FaultJaraula, C.B., Siringan, F.P. (2004). Multi-proxy reconstruction of Late Quaternary evolution of Laguna de Bai, Philippines. (Submitted to Palaeogeography, Palaeoclimatology, Palaeoecology). caused the two to break up. Interaction between Manila Bay and Laguna de Bay today occurs only through the Pasig River.
The bay was the setting for the Battle of Manila Bay in 1898, in which American troops led by Commodore George Dewey seized the area. This battle showcased the United States' naval strength. All major Spanish ships were destroyed and captured.de Castro, J.A.I. (2010). "Cleaning Up Manila Bay: Mandamus as a Tool for Environmental Protection". Ecology Law Quarterly. (37) pp
797-804 With its proud historic past and abundant marine life,MMDA-Metro Manila Development Authority
versus Concerned Residents of Manila Bay. (2008) in de Castro, J.A.I. "Cleaning Up Manila Bay: Mandamus as a Tool for Environmental Protection." G.R. Nos. 171947-48, 574 SCRA 661, 665 Philippines. Manila Bay became the ocean portal and Filipino epicenter for government, economy and industry. During the Russo-Japanese War at the close of the Battle of Tsushima in 1905, three surviving Russian protected cruisers (the '' Aurora'', '' Zhemchug'', and '' Oleg)'' managed to make port in then-United States-controlled Manila for repairs. However, because the US was neutral in this conflict, the trio of warships and their crews remained interned by the U.S. until the war officially came to an end in September 1905. During the World War II, Corregidor Island was annexed by the Japanese forces based in Manila Bay. Much earlier, various other battles were fought from this naval base, including the Battles of La Naval de Manila in 1646, which finally ended Dutch attempts to seize the Philippines.

The bay remains important for commerce and industry, including fishing, although rapid urban growth and industrialization are contributing to a decline in water quality and deteriorating marine habitats. It also serves a focus for recreation for Metro Manila and is a popular destination for walks and for viewing the sunset. Much of the land fronting the bay along Metro Manila is reclaimed land which now includes important sites such as the Philippine Senate and the Mall of Asia.

On September 27, 2011, the sea walls of Manila Bay were destroyed by the storm surge caused by Typhoon Pedring. Even the United States Embassy, Museo Pambata and Sofitel Philippine Plaza were submerged by the flooding. It was estimated that the damage would cost P30 million to repair. In April 2012, the sea walls were once again opened to the public, having been redesigned to withstand a strong storm surge.

Ecosystem

Coastal and marine habitats in the area include upland forests, mangrove, mudflats, sandy beaches, sea grass and coral reefs.

Biodiversity

A total of 19,139 birds belonging to 330 families and 99 species were observed at various monitoring sites along the bay area. The endangered Chinese Egret (Egretta eulophotes) and Black-winged cuckoo-shrike were sighted in the area. A large number of migratory birds, catfish and mackerelsMartinez-Goss, M.L. (1999).
Estimation of fish biomas in Laguna de Bay based on primary productivity- A special study of the National Statistical Coordination Board. were once abundant in these waters. Their decline ushered in the appearance of squid, shrimp, and small pelagic species such as herrings and anchovies.

Mangroves

The mangrove ecosystem around Manila Bay has both ecological and socioeconomic uses with its association of unique plant and animal species.
Of the original 54,000 hectares of mangroves existing at the turn of the 20th century, only 794 hectares are remaining as recorded in 1995.Bureau of Fisheries and Aquatic Resources – BFAR. (1995). Fisheries Sector Program – Resources and Ecological Assessment of Manila Bay. Final Report. BFAR- Department of Agriculture, Quezon City, Philippines. A few of the mangrove swamps remaining in Pampanga Bay are of considerable value for research and conservation education.National Water Resources Council - NWRC. (1983). Framework Plan: Pampanga River Basins. Report No. 24-3A. As natural habitats, mangroves considerably help in acting as a protective buffer against cyclones and storms.

Predominant in the bay area are Avicennia marina (gray or white mangrove) together with 15 species of mangroves belonging to 9 families that grow there. In the Bataan area, species of mangrove swamps that are found thriving include:
*'' Rhizophora apiculata'' (''bakhaw lalaki'' in Filipino)
*'' Rhizophora mucronata'' (Asiatic mangrove)
*'' Avicennia marina'' (gray or white mangrove)
*'' Nypa fruticans'' (nipa palm)
*''Sonneratia alba'' (no common name)
*'' Scyphiphora hydrophyllacea'' (''nilad'' in Filipino)
*''Sonneratia acida'' (''pagatpat'' in Filipino)
*''Acanthus ilicifolius'' (holly-leaved acanthus)
*'' Excoecaria agallocha'' (milky mangrove)

Plantations of '' Cocos nucifera'' (coconut palm) co-exists with the mangroves found in these areas.

Wetlands

Covering about 4,600 hectares, wetlands around Manila Bay are useful in:Alonzo-Pasicolan, S.
(1987). Status of Wetlands in Luzon. Paper presented at the Conference on Wetland and Waterfowl Conservation in Asia, Malacca, Malaysia, February 23–28, 1987. IWRB & Interwater.
*providing food and habitat for fish, shorebirds and wildlife;
*maintaining and improving water quality of rivers, lakes and estuaries,
*acting as reservoir for watersheds, and
*protecting adjacent and downstream properties of the area from potential flood damage

Mudflats, sand flats, swamps, beaches and rocky shores form part of the wetlands in Manila Bay. Found mostly along the coast of Bataan and
Pampanga, mudflats are suitable habitats for shellfish.

Coral Reefs

Contributing to the balanced functioning of the ecosystemInternational Centre for Living Aquatic Resources Management -
ICLARM (1996). Resource and Ecological Assessment of Manila Bay Philippines: Results of Monitoring Activities (1995-1996). around Manila Bay, coral reefs in the area provide sanctuary for fishes. Consequently, its decline through the years has directly affected the fish yield.

Seagrass Beds

As a diverse ecosystem, seagrass beds provide shelter for fishes and other marine life forms. Like the coral reefs, most of the seagrass beds in Manila Bay are found near its mouth, most notably in the areas of Malolos, Orion, Mariveles, and Corregidor Island.

Upland forests

Within the watershed of Manila Bay upland forests abound which are sources of food, timber, fuel wood and other products, as well as habitats for wildlife. These forests provide protection from soil erosion and help maintain the water levels and water quality in rivers and streams. Mount Makiling, Angat Dam watershed, La Mesa Dam watershed, Mounts Palay-Palay / Mataas na Gulod Protected Landscape, Mount Arayat and other portions of national parks located in Bataan, Bulacan, Rizal and Tarlac form part of these upland forest ecosystem.

Key developments

Land reclamation

Largely intended for use in human settlement and industrial development, land reclamation projects contributed to the reduction of mangroves around the area, as well as significant reduction in Metro Manila's shoreline. From 1944 to 1991, approximately 600 m of shoreline have been reclaimed in the northern part. In 2009, the Pambansang Lakas ng Kilusang Mamamalakaya ng Pilipinas (Pamalakaya) said that there are 7,000 hectares of foreshore areas in Cavite and 5,000 hectares of shallow coastal waters to expand Sangley Point naval base as part of reclamation projects which are mostly funded by foreign investors.World Justice Project. (2009). "Eco-lawyer Presses Manila Bay Clean Up". Inquirer Company, Philippines accessed at

Land conversion

Conversion of mangrove and mudflat areas into fishponds have impacted the physical features of the bay whereby what used to be irregular shoreline in 1944 has become more linear by 1977. Shoreline retreat continued as man-made structures such as fish pens occupied the coastal areas, with progradation dominant from 1977 to 1991. Most area of the bay, except those near the ports, are largely used as a major fishing ground, with fisheries and aquaculture as the dominant source of livelihood for the inhabitants in the coastal areas.

From 1990, approximately 1,200 hectares of mangroves were cleared, with the land converted for aquaculture or used as salt beds.PEMSEA. (2004) Manila Bay: Refined Risk Assessment. PEMSEA Technical Information Report No. 2004/01. Global Environment Facility / United Nations Development Programme / International Maritime Organization Regional Programme on Building Partnerships in Environmental Management for the Seas of East Asia (PEMSEA). Quezon City, Philippines. In 1993 much of the fisheries resources steadily declined due to over-fishing and over-harvesting.

Waterfront development

With then Mayor Lito Atienza's program ''Buhayin ang Maynila'' (Revitalize Manila) in 2002, the local government made the initiative of enhancing the seaside promenade of Manila through urban renewal, upkeep and improvements. What later became known as Baywalk, the facelift of the 2 km strip of central public space aimed at creating a venue for social interaction and recreation.Gomez, J.E. (2008). "Waterfront design without policy? The actual uses of Manila's Baywalk." Cities. (25) pp 86-106

With reference to its colonial history, Manila's waterfront expresses power through the dominant classesDe Barros, J., Myers, G.A., Harris, R. (Reviewer): Order and place: in a Colonial city. Patterns of struggle and resistance in Georgetown, British Guiana, 1889–1924. Verandahs of power: colonialism and space in urban Africa Urban History Review, 32(1). Fall, Toronto. which uses the Baywalk for exercise, fishing or socialization. The mix of land utilization and social activity provides public access to the edge of the sea, and counters vagrancy and mendicancy. Reviving Manila's waterfront through the Baywalk injected vibrance and historic appreciation into the public space with the statues of Arsenio Lacson, Ninoy Aquino and Evelio Javier placed in key areas.

At the onset, lack of funds hampered the revival of the Baywalk. Eventually, planning for the Baywalk means understanding and regulating diversity of functions with appropriate policy.

Legislation

Manila Bay and its corresponding resources are considered critical recipients of environmental protection. As indicated in the 1987 Constitution (Article II, Section 16) there exists legal basis for environmental protection with the provision that: ''“the State shall protect and advance the right of the people to a balanced and healthful ecology in accord with the rhythm and harmony of nature.”''Oposa, A. (1996). Legal Marketing of Environmental Law: The Philippine Experience. Proceedings Fourth International Conference on Environmental Compliance and Enforcement. United States Environmental Protection Agency National Service Center for Environmental Publications (NSCEP).USA:Cincinnati. pp 405-418

The Manila Bay Declaration 2001 recognized Manila Bay as a source of food, employment and income for the people as well as the gateway for tourism and recreation.Manila Bay Environmental Project (MBEMP).(2001). Manila Bay Coastal Strategy. Manila Bay Environmental Project (MBEMP). Quezon City, Philippines.

The Stockholm Convention on Persistent Organic Pollutants was adopted in 2001 and enforced in 2004.

Rehabilitation

Despite the issues generally associated with developing countries, such as poverty, over-population and food security, there is surprisingly a growing concern for the environmental vitality of Manila Bay. Rehabilitation, which in this case refers to an attempt to improve an aquatic system and prevent further damage to the natural ecosystems,G. Dennis Cooke (2005): Ecosystem Rehabilitation, Lake and Reservoir Management, 21:2, 218-221 is a responsibility assumed both by government and non-government organizations. The Supreme Court of the Philippines for example had issued the Metro Manila Development Authority an order to "demolish illegal structures and dwellings along riverbanks and waterways connected to Manila Bay by 2015" in March 2011 as an attempt to decrease mass occurrences of water pollution. Projects involving the wider communities include organization of the "Manila Bay Clean Up Run," which essentially supports the Philippine Environment Agencies with their objectives to raise funding and awareness towards the rehabilitation of Manila Bay's natural environments.

In 2019, the Department of Environment and Natural Resources started a rehabilitation program that is being administered by different government agencies. Because of the rehabilitation, the 10th Philippine International Pyromusical Competition that was scheduled on February 16, 2019, at the SM Mall of Asia bayside area was postponed before being moved to SM City Clark on February 23, 2019.

Beach nourishment

In the early September 2020, work began on the Manila Bay Beach which was constructed through the process of beach nourishment, which a common practice in the creation of beaches around the world. It is part of an overall integrated coastal zone management aimed at coastal defense of the Manila Bay Rehabilitation. When the Manila Bay Beach project came to wider public attention, the project has received criticism from environment and heritage conservationist groups. Among these include the timing of the project which was implemented amidst the COVID-19 pandemic and concerns of adverse environmental effects caused by dumping dolomite on the polluted Manila Bay.

According to the Mines and Geosciences Bureau, the project will benefit tourism, commerce and the environment. It will also protect coastal properties from erosion and storm surges and beach nourishment are preferred projects over hard beach stabilizing structures (such as seawalls and groynes). The Department of Health released a statement that the use of dolomite is not a known health hazard.

As with other beach nourishment projects, the area can serve as additional habitat for a number of species such as sea turtles, as well as sea birds and beach flora. When the beach was first opened to the public, a flock of Egrets were seen at the beach area.

Water quality significantly improved, especially around the beach area. The DENR reported significant drop of fecal coliform level in the waters around the beach, from 2.2 million mpn/100ml last January 4, 2021 to 523,000 mpn/100 ml in February 2021, based on the average count from three monitoring stations.

Bridges

Plans of constructing a bridge or bridge-tunnel that crosses Manila Bay have been around since 1987. In January 2020, the National Economic and Development Authority approved the plan to construct the Bataan–Cavite Interlink Bridge, also known as Manila Bay Bridge, which is expected to cross Manila Bay and connect the provinces of Bataan and Cavite. The detailed engineering design and marine geophysical surveys for the bridge are currently being completed before the start of the construction.

Water quality

Successive changes in and around Manila Bay are largely due to the intertwining impacts of continued industrialization, unrelenting increase in population, and incessant human activities catering to livelihood and habitation. These factors are directly degrading the overall environment of Manila Bay and these impacts are manifested in the continued deterioration of the water quality within the bay. Several industries operate along the bay in the highly urbanized Metro Manila area, while there are shipyard facilities in Cavite andProgramme on Building Partnerships in Environmental Management for the Seas of East Asia-PEMSEA. (2001). Manila Bay:
Initial risk assessment. PEMSEA Technical Information Report No. 2001/01, 112 p. Global Environment Facility/United Nations Development Programme/International Maritime Organization Regional PEMSEA, Quezon City, Philippines.Bajet, C.M. (2003).
Ecotoxicology of pesticides in Philippine aquatic ecosystems. In: Taylor MD, Klaine SJ, Carvalho FP, Barcelo´ D, Everaarts J, editors. Pesticide residues in coastal tropical ecosystems. Distribution, fate and effects. London: Taylor & Francis/CRC Press. pp 271–310 in Bataan, several more heavy industries, refineries and a power plant are present. At the shipping ports and ferry terminals, an average of 30,000 ships arrive and depart annually to transport passengers, manufactured goods and raw materials. Industrial waste discharges and discharges of untreated domestic wastes from drainage and sewer outletsAcorda, L. (1985). "Manila Bay Study". EMB-DENR. Quezon City, Philippines. have contributed to the severe decline in the quality of water and sediments in the bay as well as impacted on the existing marine habitats.

Salinity

According to a 2011 study by Jacinto et al.,Jacinto, G., Sotto, L., Senal, M., San Diego-McGlone, M., Escobar. M., Amano. A. and Miller, T. (2011) Hypoxia in Manila Bay, Philippines during the northeast monsoon. Marine Pollution Bulletin. 63: pp 243–248. Manila Bay has an average surface salinity of 32.6 psu (practical salinity unit). Due to the river influx, the areas near the coasts have low salinity especially in the vicinity of the mouth of the Pasig River in the eastern part of the bay. The bay's salinity is also affected by strong seasonal variations.

Effects of soil erosion

As indicated by the exposed roots of the coconut trees, continuing soil erosion has been a major factor in the changing shoreline of Manila Bay. Apart from soil erosion, other environmental processes such as siltation and sea level rise have also contributed to changing the bay's coastline. In some parts of the bay, however, erosion are prevented by seawalls and breakers particularly in areas where land has been reclaimed.

Pollution

With the presence of ports, sea-based sources of pollution around the bay are from ships and motorized boats. Twelve oil spills were recorded in 1995, but it was in 1999 where the highest total volume of oil spill occurred in the Manila South Harbor and Limay, Bataan. Increased presence of oil and grease in the waters are attributed to maritime activities at the harbors, together with the presence of oil terminals and the discharges from industries. These factors directly impacted the health of Manila Bay's waters.

Aside from oil spills, trace metals such as copper, cadmium and zinc at the surface of the waterVelasquez I., Jacinto, G.S., and Valera, F.S., (2002). The speciation of dissolved copper, cadmium and zinc in Manila Bay, Philippines. Marine Pollution Bulletin 45, pp 210-217 were found at the bay coming from sea-based and land-based (e.g., domestic sewage, industrial effluents, runoff, combustion emissions, and mining operations) sources.

In 1996, concentrations of 16 commonly used pesticides in surface sediment was found including dichloro-diphenyl-trichloroethane ( DDT).