Dredge Agusan River to solve flooding problem, says governor

BUTUAN CITY, Philippines – Following the severe flooding that hit Agusan del Sur, Governor Santiago Cane Jr. said that the key solution is to dredge the Agusan River.

Cane said this during President Ferdinand Marcos Jr.’s visit to the province on Friday, February 16, where the latter presided over a situation briefing on the effects of the trough of the low pressure Area (LPA) in Caraga.

Cane said that it will take months before the floodwaters subside to their normal level. This is because of the slow flow of the Agusan River due to siltation, highlighting the need for national government assistance.

“This (flooding) will take a while, even if it doesn’t rain anymore. Until March, there will still be floodwater. Although the number of affected barangays will decrease day by day, [for] the barangays along the Agusan River [it] will take months before the floodwater fully subsides,” he said.

When Marcos asked what could be done to speed up the flow of water, Cane suggested that the solution is to dredge the Agusan River, from its mouth in Butuan City to the upstream river along Agusan del Sur.

He added that at the mouth of the Agusan River in Butuan Bay, an island had formed in the middle of the river due to siltation, hindering the flow of water, but the local government does not have enough funds for dredging.

“I suppose we’ll just have to wait until we can put together the plan for the river. We’ll dredge it again. The siltation is really bad; it is the same problem everywhere,” Marcos said in response.

During the briefing, Cane reported that 53% of the population of Agusan del Sur was affected by the flooding. Thirteen of the province’s 14 municipalities were affected.

He reported that the total estimated amount of damage to properties, infrastructure, and agriculture is P2,295,983,284.

On January 31, the provincial government declared a state of calamity.

Potential risk of dredging

In February 2017, following heavy floods in Caraga and Davao provinces, then-agriculture secretary Manny Pinol announced the Duterte administration’s approval to dredge four major rivers, including the silted Agusan River, to mitigate the perennial flooding that cause damage to crops and properties.

A study conducted a few months after Piñol’s announcement concluded that dredging the river is an effective approach to addressing the flooding concerns along the Agusan River, particularly in terms of depth and extent as dredging allows the river to contain a greater volume of floodwater in any given scenario. However, the study noted that this approach will have a long-term negative impact.

“As dredging also smoothens the river bed, the flood velocity and the stream power along it significantly increased compared to the true scenario. This was greatly observed as the rainfall event becomes more extreme in the area,” the study said.

The study emphasized that this would greatly impact the river, potentially leading to bank erosion and sedimentation, especially considering that the much of the stretch of the Agusan River consists of bare soil.

Researchers said the study is a good reference for lawmakers on how they would take action on the planned dredging of the Agusan River. – Rappler.com

Ivy Marie Mangadlao is an Aries Rufo Journalism fellow.