Iran's Forests, Range and Watershed Management Organization has warned over 55% or about 91million hectares of national watersheds are highly exposed to flood hazards.
Around 41.5% of Iran's cities, 12.7% of villages and one million hectares of countryside, including orchards, farms, qanats (underground aqueducts) and roads, are under threat.
Recent torrential rains triggered floods countrywide, striking West Azarbaijan, East Azarbaijan, Isfahan, Gilan, Tehran and a number of other provinces.
Mohammad Yazdi, a professor of geoscience at Tehran's prestigious Shahid Beheshti University, said loss of vegetation cover is the chief culprit behind widespread, recurrent flooding.
"Floods rarely strike the areas covered by vegetation and jungles because trees will cause the raindrops to lose speed, reducing the force of impact when they hit the ground," Yazdi told ISNA in an interview published on Sunday.
Explaining other factors contributing to flooding, he said steep grounds are more prone when hit by a deluge.
"The steeper the ground, the more easily rainwater flows down," Yazdi said, citing Tehran's Valiasr street.
Sand and gravel could provide protection against flooding by absorbing the water, he noted.
"But clay soil is impenetrable meaning the water cannot filter down into the ground," he said.
Much of Iran's earth is of low permeability; therefore, water easily flows instead of being absorbed into the ground.
Besides, water that is mixed with mud is denser and is more likely to cause damage and erosion.
Yazdi noted that the risk can be managed through watershed management strategies including the improvement of vegetation.
