Expert warns of widespread flooding on both sides of Davao River

DAVAO CITY (MindaNews/17 May)–The Davao River is prone to flooding up to one kilometer on both sides if heavy rainfall accumulates in the city, a scientist working with the Department of Science and Technology (DOST) said.

Enrico Paringit, project head of the DOST’s Disaster Risk Exposure Assessment Mitigation Program (Dream), said such flooding on both sides of the river may occur if 200 millimeters of rain falls in the city.

This spans the areas starting from Waan to the mouth of the Davao River.

“If the local government sees that it is raining 200 millimeters in one of the rain stations at the watersheds, the communities near the area should take action,” he said.

Based on the rainfall intensity classification posted at http://kidlat.pagasa.dost.gov.ph/ffb/pabc.htm, a rainfall is considered heavy when it is more than 45 mm in six hours, more than 90 mm in 12 hours and more than 180 mm in 24 hours.

Paringit based his observation through the Dream tool available at the Project Noah website, www.noah.dost.gov.ph.

Speaking before the DOST’s “Iba na ang Panahon: Science for Safe Communities” disaster preparedness event on Thursday at the Grand Regal Hotel, he said that local government units should not have allowed settlements near the rivers in the first place and should have anticipated the natural movement of the river’s basin.

Davao City’s riverside communities and coastal areas have perennially experienced floods during heavy or long rainfalls.

Among the city’s flood-prone areas are Matina Gravahan, Jade Valley, NCCC Subdivision, Deca Tigatto, Gem village, Don Julian and San Rafael, according to the City Information Office.

In June 2013, a two-hour rain caused floods that led to the evacuation of at least 350 families.

Waters were chest deep in some downtown areas.

Based on the city’s Comprehensive Land Use Program (CLUP), among the locality’s challenges in terms of flood mitigation is the repair of existing flood facilities such as the waterways along the Dacudao main drain as well as the one along Roxas Avenue.

The document warns that 146,930 households in the city are at risk of floods, with 8,970 households threatened by landslides.

The CLUP also reports that there were city streets that have not been identified in the city’s flood susceptibility map but have reported some incidents of flooding, such as Inigo Street, Porras Street, and Veloso Street, among others.

Paringit’s presentation showed that the amount of water that would spill over from the Davao River would cover several communities, including riverbank settlements near the Crocodile Park and the other side of the Diversion road bridge.

He stressed that this information is readily available at the Project Noah website.

“Local governments can use this to update their CLUPs,” Paringit said.

He said there’s a need for local governments to monitor flood phenomenon not only within their jurisdiction but also those from nearby cities and municipalities.

“The thing with the Davao River is that it begins outside the boundaries of the city. You should understand the conditions upstream and adapt accordingly. Flood management goes beyond administrative or political boundaries,” Paringit said.

Instead of building a retention dam or building dikes along the riverbanks, the local government should invest in preventing the construction of houses in the riverbanks, he said (MindaNews)

URL: http://www.mindanews.com/top-stories/2014/05/17/expert-warns-of-widespread-flooding-on-both-sides-of-davao-river/

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