By Catherine Teves
Water supply problems are unlikely in Luzon’s San Roque and Pantabangan dams in October even as water levels in these areas may be below the rule curve or level that ideally enables these multi-purpose mega-facilities to ably serve respective power and irrigation customers.
Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) hydrologist Ailene Abelardo, however, said both dams may still be able to supply water for their customers.
She expects water in the dams to be sufficient by the end-October, noting there is not much demand for irrigation water during the said month.
The dams’ respective forecast end-October 2021 water levels are still above the corresponding critical low elevations of these facilities, she said.
Historical data shows the dams begin recovering and gaining water during the October-November period due to expected rainfall.
In its latest assessment, PAGASA forecast San Roque Dam’s end-October 2021 water level at 251 meters — which is 28.65 meters below the 279.65 meters rule curve.
On the other hand, Pantabangan Dam’s end-October 2021 water level may be at 204.39 meters, or 14.15 meters below the 218.54 meters rule curve then, PAGASA said further.
The weather bureau based such forecasts on expected mean rainfall of 104 millimeters and 216 millimeters over San Roque and Pantabangan watersheds this October, respectively, as well as possible water allocation in these areas.
San Roque may have an allocation of 49 cubic meters per second (CMS) that month, noted PAGASA.
The allocation for Pantabangan may be 6.82 CMS, PAGASA added.
Management of San Roque and Pantabangan can opt to adjust these allocations so the water there can increase, Abelardo said.
She is also not discounting the possibility of more rainfall actually occurring over the dams’ watersheds this October. (PNA)-rir
