Geologist sees Palisadoes danger
The Palisadoes road’s susceptibility to flooding has again raised concerns about the wisdom of closing the Tinson Pen Aerodrome and relocating its operations to the Norman Manley International Airport.
One geologist fears that rising sea levels, as well as the gradual eroding of the roadway will continue to make the road impassable during adverse weather conditions, if protective measures are not put in place.
Last week, Professor Emeritus Edward Robinson of the Marine Geology Unit in the Department of Geography and Geology at the University of the West Indies reflected on the considerable damage done to the strip during the passage of Hurricane Ivan in September 2004.
He explained that the hurricane caused a storm surge which completely overrode large sections of the eastern part of the Palisadoes, depositing debris into the harbour.
“For a few hours the Palisadoes became an island,” he said.
Professor Robinson’s concerns would have heightened on Saturday when sea water broke through the mounds of sand on the road, flooding sections of the strip and damaging some motor vehicles.
In his interview with the Observer last week, Professor Robinson reminded that in July high tides overwashed the narrowest part of the Palisadoes, moving sand and stones from the bank at the roadside.
The Palisadoes is a 14-kilometre-long spit of land which almost completely encloses the Kingston harbour. Robinson explained that spits are made up of beach sediment carried by ocean currents beyond the main shoreline.
In 1939, the decision was taken to have the airport built at its current location because it was outside of built-up areas and the authorities felt then that the area was not likely to be further developed.
But Robinson said that with sections of the strip being eroded, there is now need to examine areas of the airport itself to see if they have suffered a similar fate.
He said they are currently awaiting permission to go into the airport to examine those areas where the land was created.
That examination is even more critical now, given that the airport is undergoing a US$130-million expansion.
“We want to look at what is today, compared to what might have been there when the airport was built, because if you look at maps dated before the 1930s you will see that land was created over time to accommodate the airport,” said Robinson.
He said his team will pay close attention to the runway, which juts out into the sea and which took a bit of damage during Hurricane Ivan.
“We need to look at changes in the elevation of the area…,” he said. “On the Palisadoes strip, the harbour side is lower than the open seaside, so we need to see what is happening at the airport.”
He said the findings will be made available to the Airports Authority for the necessary action to be taken.
Robinson explained that when the weather brings rough waves, the beaches tend to be eroded, but they are rebuilt naturally during good weather. The dominant waves approaching from the Southeast, he said, attack the beaches at an angle, generating currents near the coastline which move the beach sediment gradually westward along the shore.
“In this way, beach sand that may have been near Harbour View many years ago might now have moved as far as Plumb Point lighthouse and beyond,” he explained, adding that in time it will probably reach Port Royal.
The Government, seemingly aware of the problem, has commissioned a study.
Stephen Shaw, communications manager at the National Works Agency, told the Observer that the study is part of a larger plan with the Ministry of Local Government and Environment to protect the Palisadoes road. It should also help the authorities repair the problems experienced in that area.
Shaw said the preliminary work has already started with Cubans engaged to begin some of the work which will be implemented in phases.
“We are identifying areas where there are large deposits of sand so as to create some dunes out there to really help in protecting the roadway,” he explained.
But Professor Robinson told the Observer that while there are two types of options that can be implemented, there are no measures that will offer 100 per cent protection.
The road, he said, needs to be higher than sea level to lessen flooding.
“The hurricane is a passing event, and so the road will only be flooded for a few hours, but it is the debris that is being dumped on the road which makes it impassable for days,” he said.
He suggested that vegetation be planted along the banks to prevent sand and gravel being strewn across the road.
Another alternative, he added, would be to place fences in the sand dunes.
A hard option, he explained, would be to build a concrete wall or some kind of barrier. But this, he said, may not be a good idea as whatever beach is left would be lost.
“Any option you choose you have to have maintenance, and if you get a bad storm you are going to lose it, but the barrier will help to protect the road itself from debris which takes days to be cleared,” he added.
He said that groynes, installed along the shore in the 1950s, have more or less deteriorated over the years as they have had to weather several storms.
“There used to be a very high platform and all that has disappeared,” he said, “so the road is open to immediate flooding problems if we get another storm, whether or not it is the magnitude of Ivan or not.”
Professor Robinson also agreed that the Tinson Pen Aerodrome should not be removed to the Norman Manley Airport, a position already voiced by Christopher Read, president of the Aircraft Owners and Operators Pilots Association.
In addition to the disadvantages of relocation, Read cautioned that each time the island was faced with a natural disaster, the first facilities that became incapacitated were the two international airports due to their close proximity to the sea. This, he said, had been more evident during Hurricane Ivan when relief supplies had to be flown out of Tinson Pen because the Palisadoes Road was impassable.
“Tinson Pen has survived every one of the major disasters that we have had and we have taken only a day at most to sweep off the debris before we have been able to put it back into service,” Read argued.