ILOILO CITY, Philippines -- Experts blame the worst flooding experienced in Western Visayas mainly on deforestation and the conversion of agricultural lands to subdivisions and commercial areas.

Jerry Bionat, executive officer of the Iloilo Provincial Disaster Coordinating Council, said logging activities should be investigated because rampaging waters that inundated entire villages carried logs.

Mayor Isabelo Maquino of Sta. Barbara town, one of the hardest-hit municipalities, told a meeting of the PDCC that the logs slammed into and destroyed or damaged bridges.

Bionat also noted that the flooding hit areas previously unaffected by floodwaters and many residential areas.

Water resource engineer Andrew Margarico said that while the intensity of the rainfall was a factor in the extent and magnitude of the flooding, deforestation was one of the probable main causes of the calamity.

"If there are no trees to absorb rainfall, the water will go directly downstream," said Margarico in a telephone interview.

Scientist and environmentalist Jurgenne Primavera said the flooding showed the alarming situation of forest cover, which shrunk to less than a million hectares out of a total land area of 30 million hectares.

"Water seeks its own level and unless it is held back by soil, roots and trees and forests, it will go to lower areas," Primavera told the Philippine Daily Inquirer, parent company of INQUIRER.net.

Primavera noted that until 1984 when super typhoon Undang hit, Panay Island was largely spared the onslaught of typhoons, unlike other areas like Bicol and Southern Luzon, Samar and Leyte in the Visayas.

But since Undang, typhoons have frequently hit Iloilo and its neighboring provinces. While "Undang" flooded mostly plantations, "Frank" hit residential areas and urban centers.

"We are paying for our ecological sins," Primavera said.

Margarico, a consultant with the Engineering Development Corporation of the Philippines, also blamed the rapid and extensive conversion of agricultural lands into residential areas like subdivisions.

Pavia town and the Mandurriao District in Iloilo City have been among the areas with extensive development for residential areas.

Margarico said agricultural lands also absorbed water just like the trees in upland areas.

The experts urged government to review infrastructure and development projects to check if these would have adverse environmental effects, including the blocking of natural waterways.

They cited the ongoing P8-billion Iloilo flood control project set to be completed in 2010, which would span four kilometers and aim to divert water from the Aganan and Tigum rivers to a channel leading to open sea.

Margarico said dredged soil from the project site might have blocked natural waterways.

But regional director Rolando Asis of the Department of Public Works and Highways (DPWH) said the project did not block the waterways nor did it contribute to the massive flooding.

Asis said in an interview that the abnormal amount of rainfall caused the flooding.

Bionat admitted that the damage and number of affected persons could have been lessened if agencies and local government units were prepared and had anticipated the magnitude of the calamity.

"We did not expect that we would be hit this hard and this much," said Bionat.

He said the path of the typhoon had diverted from projections based on satellite data.

Bionat recommended the strengthening of disaster management councils, organization of rescue groups and massive information campaign on disaster preparedness and response.

But Primavera said the roots of the problems must be addressed. She raised the urgent need for massive replanting especially of native trees to restore watersheds and forest cover.

She called for political will to protect environment.

"We must do this because in calamities, it's the poor people who suffer most," Primavera said.