10
Sep

PR 06 September 2013

The Mines and Geosciences Bureau (MGB) 7 of the Department of Environment and Natural Resources (DENR) has recommended the immediate closure of the Agsungot-Binaliw road located in Sitio Binaliw 3, Barangay Binaliw in Cebu City to traffic until such time that proper engineering or structural measures are put in place.

“Sitio Binaliw 3 has been rated before as high during our September 14, 2012 geohazards mapping and assessment in the area, ” said MGB 7 Senior Geologist Maria Elena Lupo.

“The road widening during that time has resulted to an almost vertical slope exposing the highly fractured or  jointed, highly weathered rocks where evidences of slope instability were already noted,” Lupo added.

“As we can see in our field investigation now, no slope protection measures were implemented since then,” Lupo said.

With this, MGB 7 recommended the continuous monitoring of mass movement, installation of warning signs to be mounted 10 to 15 meters before the active landslide zone; secure the affected zone with caution tape to avoid vehicles passing very near the foot slope; and implement a one-way traffic flow and  clear the road of landslide debris immediately.

The most recent landslide that happened in the area last August 14 covered almost the entire stretch of the road with landslide debris.

Since then, the slope has been unstable and still moving. The area has been constantly cleared of landslide debris and further road widening was done where the materials removed were utilized as road fillers in mountain barangays as alleged by Binaliw Barangay Captain Wilson Bacor.

In a field investigation conducted last September 5 by Lupo and Senior Geologist Josephine T. Aleta, they noted a 15 to 20 meter high slope cut and the road widened by around three meters from its original width.

An area along the slope face was observed to be damp giving an impression that water seepage is slowly taking place on that spot causing the materials to soften further and slide.

Lupo added that removal of landslide debris or hauling of materials should be strictly monitored or controlled as this could be a precursor to a bigger landslide, and observe a proper slope angle during the slope cutting activity.

The team also recommended that unless properly mitigated and material extraction or hauling is still going on, the affected road should be closed to traffic.

Also, an alternate scheme of traffic re-routing and alternate route for the residents of Barangay Agsungot and beyond should be properly evaluated.  Structural mitigation or slope stability measures should be immediately implemented and installed along the weak slope.

The closure should be properly coordinated with the adjoining barangays who will be affected by the road closure.

Meanwhile, MGB-7 Regional Director Loreto B. Alburo said mass movements such as landslides on slopes are usually aided by water, weathering or erosional debris cover on slopes, and the character and structure of rocks.

A landslide threat advisory was issued September 6 on the results of the assessment including the recommendations, which was received by Barangay Captain Wilson Bacor.

Alburo advised residents passing through the road to keep a close watch and to exercise extra caution and initiate readiness and measures while mitigating measures are yet to be addressed

He also added that the susceptibility rating of high was arrived during the field assessment and it should be pointed out that the rating could advance to high to very high as indicated in the latest investigation by the team.

It could be recalled that Sitio Binaliw 3, Sitio Mansawa and Sitio Campo in Barangay Binaliw in Cebu City were categorized or rated as high susceptibility to landslides in a 1:10,000-scale geohazard mapping and assessment last year.

Landslides occur when there is intense or prolonged precipitation and ground movement like earthquake.

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