Manila Bay (; ) 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, 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. 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 . Entrance to the bay is wide and expands to a width of . However, the width of the bay varies from at its mouth and expanding to at its widest point. 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. With its proud historic past and abundant marine life, Manila Bay became the ocean portal and Filipino epicenter for government, economy and industry. 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, mangroves, mudflats, sandy beaches, sea grass and coral reefs.

Biodiversity

thumb|An egret in a mangrove area along Manila Bay.

A total of 19,139 birds belonging to 330 families and 99 species were observed at various monitoring sites along the bay area. were once abundant in these waters. Their decline ushered in the appearance of squid, shrimp, and small pelagic species such as herrings and anchovies. A few of the mangrove swamps remaining in Pampanga Bay are of considerable value for research and conservation education. 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 , wetlands

  • providing food and habitat for fish, shorebirds and wildlife;
  • maintaining and improving the water quality of rivers, lakes and estuaries,
  • acting as reservoirs 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 ecosystem around Manila Bay, coral reefs in the area provide sanctuary for fishes. Consequently, its decline through the years has directly affected 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.

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. In 1993 much of the fisheries resources steadily declined due to overfishing and overharvesting.

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.

With reference to its colonial history, 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.

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.

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

On January 27, 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 for 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

thumb|left|The beach during its temporary opening in September 2020.

In early September 2020, work began on 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 received criticism from environmental 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 is preferred over hard beach stabilizing structures (such as seawalls and groynes).

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 a significant drop in 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

thumb|left|The proposed [[Bataan-Cavite Interlink Bridge will provide a permanent road link between the provinces of Bataan and Cavite. It will have a U-turn near Corregidor Island for future connection.]]

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 construction.

Water quality

Successive changes in and around Manila Bay are largely due to the intertwining impacts of continued industrialization, unrelenting increases 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 and 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. 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. 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. were found at the bay coming from sea-based and land-based (e.g., domestic sewage, industrial effluents, runoff, combustion emissions, and mining operations)

Pesticide residues from rice paddy water draining into irrigation canals, which later on empty into river systems and eventually flowing into the surrounding lakes reaches the waters of Manila Bay. Compounds from these pesticide residues find themselves in food items with metamidophos, endosulfan, chlorpyrifos and diazinon among the common contaminants. The increase in the nutrient concentration and presence of nitrate, ammonia and phosphate in the bay, from the 1980s, through to the 1990s and beyond are not only attributed to agricultural runoff and river discharges but also to fertilizers from fishponds.

Future

Sea level rise

Global warming poses a great threat to the conservation of Manila Bay and its bordering cities. With recent studies predicting that the sea level could rise between .75 and 1.9 metres by 2100 and considering the vast landscape of development, growing industries and overly dense population, the exponential assets exposed to flood-prone zones is a dire issue. The Philippine Country Study to Address Climate Change has depicted a proactive approach to this environmental issue through governance of a detailed impact assessment covering the following elements:

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Physical Environment

  • Tidal regimes including low and high levels of water circulation
  • Outlining of seasons to depict periods of high and low rainfall

Habitat and Species

  • Identification of coral species, mangrove forests, ecosystems within the coastlines, as well as nearby agricultural land

Vulnerability Analysis

  • Vulnerability maps were drawn to outline townscape in accelerated sea level timelines. Using such resources pinpoints the populated areas and natural habitats most likely to be inundated as a result of global warming

In 2010, at the occasion of the first Inter-LGU Forum on Tidal Flooding in Manila, the Dutch ambassador Robert Brinks recommended to close Manila Bay and build dykes in order to protect Manila and the surrounding provinces from the sea level rise that is expected as a result of climate change. However, he also noted that closing Manila Bay by means of a dyke would also require a new harbor location to replace the Port of Manila.

Challenges

Due to the low profile of environmentalism and its objectives within the nation of the Philippines, official awareness of global warming and the investment to applicable research is in itself triumphant. Further steps to meet the challenge of rehabilitation and sea-level rise within Manila Bay may include additional research to gain insight to the complex nature of existent ecosystems; investment to coastal protection means such as the implementation of concrete walls; Barrameda-Jimenez's body was found on 10 June 2009, over two years after she disappeared.

See also

  • Naval Base Manila
  • Battle of Manila Bay
  • Bay City
  • Geography of the Philippines
  • Manila Bay Beach
  • Pasig river rehabilitation

References

  • Fort Drum:Concrete Battleship of the Philippines
  • Biophysical environment of Manila Bay – Then and now