The Impact of Makeshift Sandbag Groynes on Coastal Geomorphology: A Case Study at Columbus Bay, Trinidad

  •  Junior Darsan    
  •  Christopher Alexis    


Coastal erosion threatens coastal land which is an invaluable limited resource to Small Island Developing States (SIDS). Columbus Bay, located on the south-western peninsula of Trinidad, experiences high rates of coastal erosion which has resulted in the loss of millions of dollars to coconut estate owners. Owing to this, three makeshift sandbag groynes were installed in the northern region of Columbus Bay to arrest the coastal erosion problem. Beach profiles were conducted at eight stations from October 2009 to April 2011 to determine the change in beach widths and beach volumes along the bay. Beach width and volume changes were determined from the baseline in October 2009. Additionally, a generalized shoreline response model (GENESIS) was applied to Columbus Bay and simulated a 4 year model run. Results indicate that there was an increase in beach width and volume at five stations located within or adjacent to the groyne field. The GENESIS model confirmed accretion within the groyne field and indicated a reduction in transport rates between groynes when compared to the rest of the bay to within 77.56 % accuracy. This study revealed that the makeshift groynes though improperly engineered, has reduced coastal erosion by encouraging accretion. The GENESIS model can be a helpful tool to inform management decisions at Columbus Bay and other beaches and bays inTrinidad and Tobago.

This work is licensed under a Creative Commons Attribution 4.0 License.
  • ISSN(Print): 1927-0488
  • ISSN(Online): 1927-0496
  • Started: 2011
  • Frequency: semiannual

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