Christopher Alexis and Isabelle Chen

Oceanography and Coastal Processes Department

IMA

Grande Riviere Beach, on the scenic north coast of Trinidad, gets its name from the large river that empties into the Caribbean Sea at the eastern end of the beach. It spans approximately 1.2 km in length and is curved with varying beach widths (Photo1).

This beach provides an important habitat for marine and coastal wildlife. It is one of the most important nesting sites for the leatherback turtle (

Dermochelys coriacea), which has been declared vulnerable on a global scale by the International Union for Conservation of Nature (IUCN) Red List and World Wildlife Fund (WWF), and nationally as an environmentally sensitive species.

Grande Riviere beach provides a landing site for fishing vessels and the surrounding forest provides great bird-watching opportunities, being home to such species as the endangered blue-throated piping-guan (pawi).

According to the Grande Riviere Nature and Tour Guide Association (GRNTGA) and the Turtle Village Trust (TVT), the main income generating activity in Grande Riviere is eco-tourism, as each year an estimated 15,000 tourists, both foreign and local, visit this community.

Beaches provide protection from coastal processes (waves, currents, tides) and are in constant flux of erosion and accretion. To the average beachgoer, each beach may appear with time narrower or wider, steeper or gentler in slope, or the same all the time.

Beach erosion can have significant impacts on coastal infrastructure such as jetties, commercial property such as hotels and guest houses, and residential properties, and therefore affects the lives and livelihoods of individuals, communities and on the country as a whole. For these reasons, the need arises for coastal-zone planning and management. These measures are needed if we want to continue to enjoy our beaches.

In recent times – 2002, 2012 and last year, 2022 – meteorological phenomena created conditions that resulted in changes to the course of the Grande Riviere River and movement of sand along the beach. In October 2022, it was observed that the course of the Grande Riviere River had been shifting westward. This shifting and widening of the river mouth led to the removal of sediment (sand) from the berm, and the easterly and westerly sections of the beach were completely separated by the wide river mouth (Image 2). The large volume of sand removed resulted in damage to coastal infrastructure and affected the local economy and posed a threat to the turtle-nesting season in March 2023.

While these changes, described as mass erosion events, may seem drastic, it is understood that this is a natural process of sediment cycling along the shoreline. With time, the sand would naturally be replenished, unless the sediment is washed too far offshore by extreme turbulent sea conditions.

[caption id="attachment_1039209" align="aligncenter" width="293"] Image 2 – Grande Riviere Bay and Beach – IKONOS Satellite Imagery -[/caption]

The westerly end of the