The beach nourishment of Manila Bay is a part of a marching order issued by the Supreme Court, a writ of continuing mandamus dated Dec. 18, 2008, whereby the Supreme Court ordered/directed 13 government agencies to spearhead the clean-up, rehabilitation and eventual preservation of Manila Bay. Such agencies, include the following: Metropolitan Manila Development Authority (MMDA), Department of Environment and Natural Resources (DENR), Department of Education (DepEd), Department of Health (DOH), Department of Agriculture (DA), Department of Public Works and Highways (DPWH), Local Water Utilities Administration (LWUA), Metropolitan Waterworks and Sewerage System (MWSS), Philippine Ports Authority (PPA), Department of Budget and Management ((DBM), Philippine Coast Guard (PCG), the Philippine National Police (PNP) Maritime Group, and the Department of Interior and Local Government (DILG). These said agencies were given ten (10) years to accomplish the project with a standing order to "clean-up, rehabilitate, and preserve Manila Bay, and restore and maintain its waters to SB level to make them fit for swimming, skin-diving, and other forms of contact recreation.", as the case had stemmed from a complaint filed by a group called the "Concerned Residents of Manila Bay" before the Regional Trial Court in Imus, Cavite against the government agencies for the preservation and protection of Manila Bay
As the lead agency tasked with the bay’s cleanup, DENR launched its campaign to spread awareness of the bay’s sorry state dubbed “Manila Bayanihan: Para sa Kalinisan” on January 27, 2019 at Barangay Zapote V, Bacoor, Cavite. To celebrate the first year anniversary of the Battle for Manila Bay last Jan. 26, 2020, the DENR has lined up several activities including the inauguration of the sewage interceptor and treatment plant located in front of the Manila Yacht Club. This facility is capable of treating 500,000 liters of wastewater per day in order to ensure that no untreated wastewater from the drainage outfalls flows into the bay.
As proven by teams from the Mines and Geosciences Bureau’s geologists who conducted coastal geohazard assessment Marine Geological Survey Division, most beaches in the Philippines are prone to erosion which cause adverse changes in the shape and position of coasts. Coastal erosion became an issue because most Filipinos had preferred to settle along the beach. With more people wanting to develop the beach, they searched for methods to protect their properties. In this spectrum of protection of beaches and properties against the powerful erosional forces of seas and oceans, soft structures like beach nourishment are preferred over hard beach stabilizing structures (like sea walls and groins). Construction of seawalls in some cases lead to coastal erosion causing changes in shore sediment dynamics and even affectbut also adjoining coasts. Having both its benefits and drawbacks to tourism, commerce and the environment, this coastal nourishment is now the common practice in most countries like the US, France, Vietnam, Australia, Belgium and other countries.
In 2002, the French capital introduced the idea of the “Paris Plage,” which later became “Paris Plages” or Paris Beaches.
Trucks of sand along with palm trees were laid in Paris along the River Seine. Just like Manilenians,
the Parisians are critical, and angry on the superficiality as well as the cost of the project.
The baywalk in Manila Bay after its rehabilitation last year. (Photo featured in Manila Bulletin by Lost Juan, Sept 4)
Beach nourishment, or beach replenishment, is the practice of adding sand or sediment to beaches to combat erosion and increase beach width. Sand feeding is, likewise viewed as an alternative to beach armoring. However, it is important to note that beach nourishment does not stop erosion, rather, it merely prevents erosion for a short time. Beach nourishment is a soft engineering alternative to hard structures (like seawalls, groins) on the shore used to create a natural beach environment for the bay, eliminating detrimental effects of shore protection structures by burying them, and retaining sediment volumes to respond to sea level rise brought about by climate change. This scheme is practiced extensively in developed countries and is the preferred strategy for combating erosion and protecting coastal communities. After the dredging and clean-up of the Bay, the members of the different agencies involved have agreed that the initial beach nourishment to be implemented will be applied in the segment between the area fronting the US Embassy and the Manila Bay Yacht Club to mimic a “pocket beach”.
Continuing its efforts to curb the pollution in Manila Bay and rehabilitating the beach, the Department of Environment and Natural Resources (DENR) began laying out white sand made from crushed dolomite rocks last week. This is part of the PHP 389-Million Manila Bay rehabilitation which began two years ago, which now faces criticisms due to the use of “white sand”. Manila City Mayor Francisco “Isko Moreno” Domagoso does not see any problem which requires the operation to stop, noting that according to the Department of Health, the mineral dolomite, when coming in its “bulk state”, is not a known health hazard. DENR clarifies that based from Wentworth (1922) Grain Size Classification from the United States Geological Survey Open-File Report 2006-1195 dated 2011, the sand grains spread in Manila Bay is classified as coarse-grained sand to fine pebbles. This is 2 millimeters to 5 millimeters in size or equivalent to 2,000 microns to 5,000 microns, and therefore almost 100 times bigger than dust. This is not “dust” which is 2.5 microns to 50 microns in size. Dust was the one mentioned in the news that is hazardous if inhaled. They further cite that famous islands known for their fine sand such as Panglao and Boracay became world-renowned from their “powdery sugary sand”, which came were derived from weathered coralline limestone and dolomitic limestone, and no health complaint has been filed by tourists and swimmers.
In response to these clamor it is important that DENR had conferred the activity with other agencies before the implementation of the project. Based on previous studies, it is understood that beach nourishment is not a permanent remedy to the Manila Bay issue. According to studies and scientific researches, mechanically placed sand on beaches moves as affected by waves, currents, tides and wind and other potential impacts of anthropogenic and natural events. The study in San Diego County, California published in the journal Coastal Engineering, could help planners develop beach nourishment projects that will reach their intended goals without causing unintended problems. In this study of Scripps Institution of Oceanography at the University of California at San Diego, they found out that added coarser sand to the beach stayed on despite of energetic waves. In one case, the sand moved both north and south along the coast that later contributed to the closure of a river estuary causing concentrated pollution and hypoxia.
In the case of the Dolomite sand spread along the beach of Manila Bay, systematic monitoring of monsoon or seasonal currents should be done to follow the general pattern of the direction of movement and deposition of piles of sediments in the bay. The process will take for some time but regular monitoring and studies will enable DENR to predict or model on how the nourished sand will evolve.
By: Marine Geological Survey Division