Spring tide sweeps away mangroves at Mahaicony

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Sea Defence Breach at Mahaicony. [File Photo taken from Guyana Chronicle]
The Ministry of Public Works is assessing the impacts of the current spring tide on the sea and river defences in vulnerable locations along the coast.

Engineers from the Ministry have been monitoring critical stretches of coastline impacted by the spring tide and measures are being taken to minimise potential flood impacts.

The current spring tide, which commenced on September 15th and will be active until September 22nd, is one of the most pronounced for the year 2020. Based on the published tide tables, high tide levels in excess of 3.3m above Chart Datum will be experienced, with a maximum high tide level of 3.32m above Chart Datum on September 18, 2020.

According to recent meteorological reports, a total of five tropical cyclones are currently active in the Atlantic Ocean. The five systems are Hurricane Paulette, Hurricane Sally, Tropical Storm Teddy, Tropical Storm Vicky, and Tropical Depression Rene.

Expert meteorologists have indicated that this is a notable development, since the only other recorded instance of five simultaneously active weather systems in the Atlantic was in 1971.

Tropical storms and low-pressure systems, when combined with spring tide effects, characteristically contribute to a more aggressive wave climate and increases nearshore wave energy. The Ministry is currently consulting with the Hydrometeorological Department to determine the potential influence of active Atlantic weather systems on the nearshore wave climate along the Guyana Coast.

Vulnerable areas along the coast may experience mild to be severe flooding due to overtopping of revetments, seawalls and earthen embankments during the current spring tide period.

At Mahaicony, East Coast Demerara, the critical condition of the shoreline has escalated due to the impacts of the current spring tide. This has resulted in overtopping of ongoing sea defence works being executed between Fairfield and Content.

Between Content and Mes Delices, rapid depletion of the remaining mangrove fringe has occurred over the past 48 hours leading to exposure of 500m of embankment to erosion and overtopping.

A similar condition has developed between Fairfield and Bath leading to the exposure of the earthen embankment to direct wave impact and overtopping releasing salt water into the adjacent Bellamy Canal.

Four major sea defence contracts were awarded in September, 2020 for the construction of a total of 2km of permanent sea defence structures, which will address these critical areas.

All contractors are currently preparing to mobilise to the respective sites to initiate these flood protection works.

Additional vulnerable areas being closely monitored include, Cullen and Onderneeming on the Essequibo Coast; Cane Garden, Cane Field, Elizabeth Ann, Waterloo, Maryville, Retrieve and Blenheim on the island of Leguan; Zeelandia, Maria Pleasure, Belle Plaine, Sans Souci, and Moorfarm on the island of Wakenaam; Parika, Den Amstel, Anna Catherina, Hague, and Utivlugt on the West Coast of Demerara; New Hope, Good Success, Friendship and Garden of Eden on the East Bank of Demerara; Helena along the Mahaica River; and New Amsterdam, Sheet Anchor, Wellington Park and No.54 to No. 61 Village, Corentyne, Region 6. The Sea and River Defence, Force Account Units have been working to heighten vulnerable sections of earthen embankment and reinforce stretches of revetment and sea walls to minimise the extent of overtopping.

Where considered necessary, contractors have been engaged to reinforce and heighten revetments and desilt drainage canals that function to contain overtopping discharge, as well as community drains. Major rehabilitation and reconstruction interventions have been programmed to strengthen the flood protection infrastructure in all impacted areas.

The Ministry provides its assurance that the Sea and River Defence Department will continue to actively pursue the required measures to mitigate the impacts on flooding on coastal communities. Residents of low-lying coastal communities are advised to take the needed precautions during the remainder of the spring tide period.