Tue | Jan 19, 2021

Geologist urges strengthening of ‘no-build’ zones

Published:Wednesday | November 11, 2020 | 12:15 AMPaul Clarke/Gleaner Writer

Professor of Sedimentary Geology in the Department of Geology and Geography at The University of the West Indies, Mona, Simon Mitchell, is urging the Government to enforce no-build zones to protect lives and property in adverse weather episodes.

Noting the magnitude 3.4 earthquake which was felt in sections of the island on Sunday, November 8, during the pummelling rain, Mitchell, who is also the director of research at the Earthquake Unit, said there is concern that a “strong enough” tremor coupled with the drenched earth could create massive problems.

“When the ground is saturated like this, if we get even a small earthquake, something in the region of a 4.5 magnitude, we could see some very major landslides because all of the hillsides are soaked and are ready to be pulled down,” said Mitchell.

“That would be worst-case scenario.”

Dozens of homes in Nine Miles, Bull Bay, St Andrew, were left under floodwaters, heavy silt, and other debris following the weekend rains, and is likely to cost Government billions of dollars in repairs.

Mitchell echoed the chairman of the Kingston and St Andrew Municipal Corporation (KSAMC), Delroy Williams, who told the council yesterday that soil instability and the massive silt flow in sections of St Andrew is now a major worry.

The geologists identified sections of the country, primarily the hilly eastern parts of the island – St Mary, St Andrew, Portland, St Thomas and the eastern parts of St Andrew – that are prone to land slippage because of the types of soil there.

There are communities in that side of the island that sit on older rocks and a lot of these older rocks are igneous rocks, sandstones, conglomerates and shale.

“I think we have to be thinking about planning in terms of how we are going to go forward. So wherever we are building, we need to be thinking of the merits in relation to safety and preservation,” Mitchell noted.

Near three weeks of tropical downpours have resulted in billions of dollars in damage to farm lands and other properties, homes and road infrastructure.

SOIL EROSION

The torrential rainfall on the weekend left a trail of destruction, including a massive breakaway on a section of the Gordon Town Road in east rural St Andrew.

“These rocks, they all weather very heavily and they do so through clays and sand and silt, and that is the material that comes down these rivers. It doesn’t help if you start clearing the hillside for farming purposes because natural vegetation tends to keep them in place, and when you actually clear the natural vegetation, you end up with soil erosion,” said Mitchell.

“So if we interfere with the hillside and cut down the trees to expand coffee farms, for example, what you end up with is more erosion.”

Mitchell said the Government must begin taking stock of where vulnerable communities are located and to begin addressing them in a more serious way.

“There are places definitely where we would say we shouldn’t build here and establish a ‘no-build zone’ because it is too dangerous and people could lose their lives otherwise,” the geologist said.

Williams, meanwhile, indicated that he has asked the engineering and planning department to take steps to gather data and working closely with the mining and geology department to share and gather data in that area, primarily for development and land-use purposes.

“It is a part of our Local Area Sustainable Development Plan. In addition, there is a partnership being developed between ourselves and an international university to conduct research in the eastern section of the municipality as it relates to our soil instability,” he stated.

Speaking to the damaged Gordon Town Road, Williams said initial assessment of the area is that it will take some time to rebuild that section of the roadway.

He said the KSAMC took time on Monday looking at the state of alternative routes to bypass the damaged roadway in order to reach communities that are affected, to include Content Gap, Hagley Gap, Mavis Bank, Maryland and Westphalia.

paul.clarke@gleanerjm.com