BEACH DAMAGE...coastlines could take months to recover
Web Posted - Wed Mar 26 2008
By Shawn Cumberbatch
IT could take beaches along Barbados' east, north and west coasts more than two months to recover from last week's battering by the sea.
Director of the Coastal Zone Management Unit (CZMU), Dr. Leo Brewster, gave this initial assessment yesterday as CZMU teams began determining the full impact of the nine to 18-foot waves which pounded some of the island's popular beaches.
Speaking during an interview with the Barbados Advocate, he also said that his organisation is working out the logistics of investigating coral reef and other damage at more than 20 dive sites on the west coast, before starting that work either later this week or next week.
Brewster said it typically took between two and eight weeks for beaches to recover to "near normal condition" after such erosion, depending on how close the sand had been deposited offshore, but he cautioned this could take longer if the sand was in deep water, or if more bad weather came calling.
"Once the wave energy has calmed right down there is then a period of recovery that would start to take place and once the sand is close enough to the shoreline then within two weeks you can possibly start to see recovery, but we normally have to give it, at a minimum, four to six weeks or longer for the beaches to recover. So we just have to hope that there are no more bad weather systems out there between now and the beginning of the Hurricane Season," he said.
The director explained that CZMU was scheduled to start its quarterly beach profile yesterday, therefore experts from that entity would be able to fully assess the damage over the next two and half weeks without having to use additional resources.
With the last beach profile having taken place in December, Brewster said they would be able to "actually measure the height and width of the beach in profile at specified distances from a fixed point within that beach area. That information helps you calculate the slope of the beach and can actually assist in calculating approximate beach volumes, in terms of how much sand has been lost or shifted in position".
"When you compare the profile to the last time, or other previous times that you would have done it, you would then be able to see changes/variations. Because of the storm waves, the position of the high water mark (where the waves would have been breaking and uprushing on the beach) would have shifted much further inland now because of the storm. And therefore if a lot of sand has been lost or pushed up onto the back beach area, you can calculate how much the beach volume has been changed," he noted.
The official said the large sea swells had not taken the CZMU by too much surprise, since large waves were normally expected around Easter. What was, unusual, however, was the frequency and direction they came from.
"We normally expect large waves at Easter time, not as high or as persistent as those, but there have been instances where three-metre waves have come in the past. When we even had that major erosion in 2006, we had three-metre waves coming in regularly, so it isn't really and truly unfamiliar... in that case, however, the wave direction had been predominantly from the south. I think the real issue was that the waves in this recent event were coming straight down from the north and that's why a lot of damage was really done on either side of the coastline," Brewster stated.
Meanwhile, the CZMU spokesman said teams would be visiting some of the more popular dive sites "to look for damage from the waves, in terms of large coral heads being dislodged or broken off".
"Also, we will be looking to see if there is evidence of a lot of sand being deposited on the reefs or not. We will normally have to do that through transect lines and video recording and that sort of thing. It might take as long as a month because we can only do two tank dives within one day and you have both near-shore and offshore reefs in varying water depths to do. We will do a general reconnaissance first to identify which areas were the worst hit, and then go back and plan how we are going to deal with those areas intensively," he explained.
Brewster said the teams would try to assess each of the more than 20 sites along the west coast that are regularly used by dive operators, once time and other factors permit.
"If it proves too difficult, then we will prioritise which ones we should go to because some have unique features that are important as attractions. So you might start with them first and then phase in the others as we go. Where there are wrecks or sites that have actual physical features which give rise to some of the dive site names, we need to make sure they are still there," he said.
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