Jalaur dams reduce flooding in Calinog, experts claim

The implementation of the Jalaur River Multi-Purpose Project Stage II (JRMP II) in the Province of Iloilo is 60% completed as of October 2022.

During the onslaught of Tropical Storm Paeng in the Province of Iloilo, the Jalaur Dams were noted to have reduced the effects of flashfloods in the Municipality of Calinog where major project facilities are being implemented.

Korean dam experts from the Joint Venture Consultants from Korea Rural Community Corporation (KRC), Saman Corporation, and Dasan Consultants Ltd. Corp. claimed that the Jalaur High Dam and Afterbay Dam, which are still under construction phase, reduced 71% of the flooding in the downstream portion of the town of Calinog.

This means that the high dam, which was 55.1 meters high during that time, temporarily collected an estimated 13.8 billion liters (13.829 million cubic meters) of flood water with a maximum height of 35.1 meters from the riverbed (equivalent to more than 11-storey tall building) and discharge rate of 1.185 million liters of water per second before these were released to the Afterbay dam.

At the tail end of the Afterbay dam diversion tunnel, the flood height was recorded at 8 meters high from the riverbed (equivalent to almost three-storey building) and discharge rate was reduced to 343,300 liters per second because of the temporary stoppage of flashflood at the high dam and the constricted discharge of floodwater back to Jalaur River.

Experts believe that if the dams did not create a temporary water storage effect in the mountainside, there could have been widespread and massive flooding in the downstream and heavily populated areas of Calinog and nearby towns because the river was already on critical level since October 27, 2022.

The Province of Iloilo was placed under the Tropical Storm Signal No.1 from October 27 until November 1, 2022.

On top of that, an Orange Rainfall alert was likewise hoisted in the province during the same period which meant that rainfall in the area was estimated to be 15-30 liters per square meter.

“While we are still on the Construction Phase, we are happy to note that the dams helped a lot in mitigating flooding within the project site” said Engineer Jonel Borres, JRMP II Project Manager.

Manager Borres likewise said that with this report highlights the need for the project to be completed on time so the Ilonggos can enjoy all its benefits very soon.

Considering current construction progress, the project is expected to be fully operational by mid of 2024.

JRMP II is the first large-scale reservoir dam in Western Visayas that is expected to boost rural development through the multi-purpose utilization of the Jalaur River.

Among these benefits is mitigation of flooding which is a perennial problem among towns within the Jalaur River valley. (Steve Cordero)