Pampanga reflects on lost rivers
RUNNING DRY More stones and sand than water fill the upstream of the Pasig-Potrero River southwest of Mt. Pinatubo. TONETTE T. OREJAS/INQUIRER CENTRAL LUZON
(First of two parts)
BACOLOR, Pampanga—Ernesto Ocampo feels a big sense of loss, while provinces in the shadow of Mt. Pinatubo prepare to celebrate the resiliency of more than 8 million survivors of the volcano’s major eruption 25 years ago.
The 65-year-old farmer is thankful that he survived the volcanic eruption, the world’s second largest in the 20th century, as well as the lingering disaster that followed due to a rampage of lahar (volcanic debris washed down by rains from the slopes).
But Ocampo says he has yet to imbibe the celebratory mood because he has not been able to return to his village, Mesalipit, which has remained a no man’s land.
Like its name, Mesalipit is trapped in a triangle formed by the San Fernando-Santo Tomas-Minalin Tail Dike, Gugu Dike and a new dike being built connecting the two older dikes.
Sediments flowing from the erstwhile Gugu Creek have accumulated in the village, raising its level. Gugu is now a river that drains the original channel of the Pasig-Potrero River. But during dry months, it is a wide field of sturdy grass, turning back into a big pool of water when the monsoon returns.
Ocampo says a tributary called Gulut Kubu is gone. “That’s where we used to get fish and water for planting rice,” he said.
He abandoned the Madapdap resettlement in Mabacalat City in 2013, opting to live and farm beside the tail dike where, at its base, a new river formed during the rainy months.
This new river drains San Fernando River in the Pampanga capital to the Pasac River at the mouth of Manila Bay.
San Fernando River takes in water from Sacobia and Abacan rivers in Tarlac province and Angeles City via Mexico town in Pampanga. Pasac River drains out all tributaries from the south eastern side of the volcano.
To date, there has been no inventory of smaller rivers that have been erased or formed in the landscapes of Pampanga, Tarlac and Zambales provinces after the June 15, 1991, eruption and the subsequent lahar flows.
Trapping lahar
Neither has there been a study by the Department of Environment and Natural Resources (DENR) on the biological health of eight major rivers draining from Mt. Pinatubo that have been the focus of engineering interventions to trap lahar or ease flooding.
These are the Crow Valley-O’Donnell and Sacobia-Bamban rivers in Tarlac; the Abacan, Pasig-Potrero and Porac-Gumain rivers in Pampanga; and the Marella-Sto. Tomas, Maloma and Balin Baquero-Bucao rivers in Zambales.
These rivers became biologically dead “only immediately after being covered [by volcanic debris] because of the chemicals,” said Edgardo Gomez, a national scientist for marine biology.
But Gomez said organisms would recolonize these waterways in time.
The eruption of Mt. Pinatubo, which lasted for nine hours, deposited 6.7 billion cubic meters of pyroclastic materials on the slopes of the volcano.
Some 4.7 billion cubic meters (or 70 percent) of these volcanic debris were deposited in areas around the Bucao, Maloma and Santo Tomas rivers, the Department of Public Works and Highways (DPWH) said in a 2003 study.
Quarrying
Kelvin Rodolfo, a geologist, said “continuing heavy quarrying [on former riverbeds] can’t do anything but harm the flora and fauna.”
In the provinces of Pampanga, Tarlac and Zambales, sand is extracted to supply the construction industry.
It has taken longer for eight rivers linked to the watersheds of Mt. Pinatubo to come back to life and feed their pre-1991 eruption tributaries.
These waterways are dredged or diked or their channels diverted to increase their capacity to hold lahar or reduce floods, according to the DPWH. Siltation is a recurring problem as rains erode lahar.
Renato Solidum, chief of the Philippine Institute of Volcanology and Seismology (Phivolcs), said fish could not thrive in rivers that were frequently dredged.
Some fishermen have observed that mild saline water have not been coming inland during dry months to support fish that can grow in rivers.
Several farmers inside the FVR Megadike believe that the original channel of Pasig-Potrero River has shifted to the west and is blocked by 6-meter-high lahar on the side of Guagua and Santa Rita towns.
Filled with rainwater, the channel has thrived with “kangkong” (water spinach) and fishes, evident in the many elevated sheds used by fishermen.
Birds of all sorts come to feed there. (To be continued Tuesday)
