Addressing Pampanga, Bulacan flooding

Bulacan and Pampanga have been placed under a state of calamity, with 22 towns in Bulacan and 16 in Pampanga still under heavy flooding from the rains caused by Typhoons “Egay” and “Falcon,” and the southwest monsoon. Floods with depths reaching seven feet have persisted for about two weeks and affected the daily life of the residents.

In coming up with long-lasting solutions to the flooding problem, there is a need to employ the watershed land use planning approach. This is an integrated area approach that considers flood-prone areas as parts of watersheds with uplands and lowlands, that have interconnected ecological processes. The flood-prone areas we’re concerned about are actually parts of the interconnected Pampanga and Bulacan watersheds, drained mainly by the Pampanga and Angat rivers. Public and private efforts so far are jointly focused on addressing problems related to natural water flows.

Aside from heavy rainfall caused by atmospheric events, we can trace the causes of flooding, firstly, to the rampant denudation of forests in the Sierra Madre mountains. Trees absorb water and slow its movement to the lowland, while at the same time preventing soil erosion that could result in the silting of the river system. The silted rivers in the coastal towns of Pampanga and Bulacan easily experience overflowing of their banks, especially during abnormally high rainfall events. The silting and resulting shallowing of the rivers are also traceable to the accumulation of ashfall and lahar ejected by Mount Pinatubo in 1991, and the garbage dumped into the rivers by residents. The flooding is further exacerbated by the subsidence caused by the pumping of groundwater by residents and fishpond owners in an already very level terrain.

Considering the above causes of flooding, certain actions need to be given urgent attention. First, intensified reforestation should be conducted in denuded parts of the Sierra Madre mountains, especially those whose slopes are above 50 percent. Second, dredging should be extensively done in the silted rivers, including parts of Manila Bay at the mouth of major rivers. An example of private sector participation in this activity is the dredging being done in the silted Marilao-Meycauayan-Obando River System by San Miguel Corp. Third, river widening should be done, and concrete channels or canals in major rivers should be established.

Actually, this was already done in the Pampanga River by the Department of Public Works and Highways in the 1990s under the first phase of its Pampanga Delta Development Project. The river channeling activity under the project’s second phase should have moved up around Calumpit and moved down along the Labangan River. But this was aborted by the strong lobby of the Calumpit local government, which claimed that a sizeable part of its area would be eaten up by the project. The river widening solution should also be extended to the widening of transportation channels coursing through the fishpond structures.

Fourth, water-impounding structures should be set up on the higher levels of the river basins and watersheds for the purpose of stalling the onrush of water that leads to flooding downstream. The government plans to set up a 200-hectare water-retarding basin in the Candaba Swamp above the Pampanga River, as well as a small water-impounding project in Cuyapo, Nueva Ecija. More of these projects should be set up on the higher elevations of the river basin.

Fifth, the pumping of groundwater that creates subsidence should be regulated. Incidentally, the saltwater intrusion that also results from this activity has already reduced the agricultural areas as they are converted into fishponds.

Lastly, there is a need for an intensified information, education, and communication campaign among stakeholders for the implementation of these projects that would benefit them in so many ways, including the enhancement of their socioeconomic development.

Meliton B. Juanico is a retired professor of geography at the College of Social Sciences and Philosophy, University of the Philippines Diliman, and is a practicing licensed environmental planner.