The National Irrigation Administration (NIA) will be releasing water from Magat Dam in Isabela on Sunday, Oct. 10, in anticipation of heavy rains from tropical storm "Maring" (international name "Kompasu") and tropical depression "Nando," said the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).
PAGASA's Hydro-Meteorology Division received NIA's notice of dam discharge warning operation on Saturday, Oct. 9, informing the agency that Magat Dam will release water from the reservoir starting 3 p.m. Sunday.
"Reservoir elevation needs to be lowered in anticipation of the expected heavy inflow due to typhoon Maring and typhoon Nando," NIA's advisory read.
Based on the PAGASA's monitoring as of 6 a.m., Saturday, Magat Dam's water level was 188.32 meters, or less than 5 meters below its 193.0-meter spilling level.
PAGASA said that the catchment of Magat Dam is huge but the reservoir is small thus it tends to be filled up quickly during a heavy rainfall event.
Moreover, the regulation of outflow from Magat Dam is conducted to mitigate potential flood damage to the downstream communities.