Conference Presentations by Junior Darsan Ph.D.
Sustainable coastal ecosystem management – an evolving paradigm.
With our growing global population, over-consumption of natural resources and concomitant depleti... more With our growing global population, over-consumption of natural resources and concomitant depletion, demands are placed on the scientific community to provide information, including suitable management of coastal ecosystems. However, the nature-society relationship is highly dynamic and complex and requires a framework which can accommodate options. In coastal systems, poor resource management is among the main causes of its degradation. As such, impacts arising from climate change, including sea-level rise, has forced an increase in the demand for sustainable coastal ecosystem science to inform management decisions. The realization of current and future sustainability objectives depends on the development and implementation of coherent strategies on managing dynamic ecosystems for retaining their ability to undergo disturbance, while maintaining their services, functions and control mechanisms. This paper provides a review of the basic assumptions, typical frameworks and methodologies that are adopted for (i) sustainability and sustainable management, (ii) ecosystem services and ecosystem management and (iii) coastal ecosystem management applications in Caribbean Small Island Developing States (SIDS). Finally, limitations for sustainable coastal ecosystem management are discussed and recommendations are made which can inform research in sustainability science.
A barrier beach system under threat; Cocos Bay, Manzanilla,
Manzanilla beach in Cocos Bay is a barrier beach under threat from marine erosion due to the hi... more Manzanilla beach in Cocos Bay is a barrier beach under threat from marine erosion due to the high energy environment of the Atlantic Ocean. This barrier beach borders the Ramsar Convention designated Nariva Swamp and the beach plays a critical role in the function of this fragile wetland ecosystem. This relationship also serves to impact the wetland as ongoing coastal erosion occurring at Cocos Bay beach threatens the longevity of this ecosystem. By virtue of its geographical location it is constantly being exposed to Atlantic-generated storm events, which is exacerbated due to the low relief of the study area. The data show that coastal erosion and storm surges have the potential for breaching the barrier beach, and vulnerability to tsunami threats, further magnifying the possible impacts. This paper reviews all the studies conducted on this environmentally sensitive area. It includes studies on coastal erosion, storm surges, tsumamis and episodic wetland flooding. It examines the various issues and the challenges with regard to management and outlines recommendations to minimize the impacts from these hazards. It goes on to highlight the inter-relationship and dependence that exists so as to better manage this area as an ecosystem, rather that the ad hoc approaches which is currently the focus by planners. This paper provides more information to further our understanding of the dynamics and challenges of barrier beach systems in an attempt to ensure sustainable development and maintenance of these volatile environments. This is required urgently, if Trinidad and Tobago is to adequately respond to the threat posed by the effects of climate change especially sea level rise and subsequently build its coastal resilience.
Cusp morphodynamics in a micro-tidal exposed beach.
Beach cusps have attracted the focus of several studies due to their effect on sediment transport... more Beach cusps have attracted the focus of several studies due to their effect on sediment transport and their rhythmic presence in the midst of complex nearshore interactions among waves, currents and sediment.
In this paper, cusp evolution is investigated to determine the factors which influence them within Maracas Bay, Trinidad, in the micro-tidal environment of the southern Caribbean. Data on beach profiles, beach
sediment, coastal processes, and cusp dimensions were collected using standard geomorphological techniques across daily, weekly and seasonal time-scales. Results indicate that beach cusp dimensions are
predominantly determined by beach volume and beach angle. These two parameters in turn are influenced by wave energy. In both the wet and dry seasons, periods of lower wave energy promote accretion, leading to the formation of smaller beach cusps; conversely, periods of higher wave energy and the associated increase in erosion result in the formation of larger beach cusps. There was agreement with the selforganization
theory since cusps were always present along the beach, constantly changing morphologically but never completely being erased and recreated anew. Beach cusps form an integral part of the total sediment deposited and retained on beaches over tidal and seasonal cycles, with implications for nearshore currents and beach safety. As such, a proper understanding of their dynamics will help support
planning and management of beaches as they go through cyclic phases annually.
Status of beaches and bays in Trinidad (2004-2008).
The interaction of the hydrologic, oceanographic, and geomorphologic facets determine the state a... more The interaction of the hydrologic, oceanographic, and geomorphologic facets determine the state and sustainability of beaches at river mouths. Grande Riviere beach located on the North coast of Trinidad is an internationally recognised critical habitat serving as a prime nesting ground for endangered leatherback turtles (Dermochelys coriacea) and subjected to this environmental control. Episodic extreme flooding of the Grande Riviere River has led to the shifting of the river mouth with associated exaggerated backshore beach erosion. The 2012 event has been identified as the most severe, with negative implications for coastal infrastructure and a successful turtle nesting season. Subsequent human intervention through the construction of a sand dam to arrest further erosion, precipitated a host of new problems ranging from beach instability to public health. This paper presents a geomorphological analysis of beach dynamics for Grande Riviere. Data on beach profiles, sediment and coastal processes were collected from 2003 to 2013 using standard geomorphological techniques. Beach topography was surveyed monthly from July 2013 to January 2013, alongside water quality tests on impounded water in the erosion channel. Results from topographic surveys indicated that the backshore erosion channel left in the wake of the river shifting event and anthropogenic intervention was 4,843.4 m3. Public pressure for infilling of the erosion channel through sand relocation was overruled, due to limited in situ geomorphological data and the beach's ecological and socio-economic fragility. In January 2013, high energy swell waves naturally in-filled the erosion channel, and started the repair to the beach, which continued over the following months. These observations show that the influence of the hydrologic and coastal geomorphologic interplay is responsible for the existence and sustainability of this coastal system. Therefore, effective integrated Proper management of such critical habitats remains dependent upon continuous monitoring data to inform policy and decision making .
Assessing the Equilibrium Status of Beaches in Trinidad, W.I.
"The shoreline monitoring component of the Coastal Conservation Project which commenced in 1988 p... more "The shoreline monitoring component of the Coastal Conservation Project which commenced in 1988 provides valuable insights on the dynamics of the coastline. The scientific data are used by government and other agencies in formulating policies and plans for the coastline. While coastlines of Trinidad and Tobago are monitored under this project, this report presents only the research conducted in Trinidad during the period 2004 – 2008. The report focuses on the 25 beaches and bays monitored, comprising 64 beach profiling stations. The report reveals that most of the beaches and bays in Trinidad are in a state of dynamic equilibrium where the seasonal changes of erosion and accretion occurring on the beaches revolve around a state of stability.
The beaches on the north coast are less prone to erosion due to the more resilient metamorphic rocks that form these bays. However, changes in sand elevations due to normal wave processes do occur. During the period 2004–2008 all beaches monitored on the north coast experienced a state of dynamic equilibrium with the exception of the east and west stations at Las Cuevas Bays and the western part of Blanchisseuse Bay.
All east coast beaches also experienced dynamic equilibrium except the southern part of Cocos Bay. Erosion in this part of the coastline threatened to breach the roadway and prompted government to construct a 2 km long rip rap revetment as a means of shoreline protection. This has curbed the erosion in the protected area but to the extreme south erosion is ongoing at a rate of 2.5 m/yr since 2005.
The beaches on the south coast experienced dynamic equilibrium except at the western section of Guayaguayare Bay. Erosion in this part of the bay averaged 1.20 m/yr since 2004. This erosion can be attributed to both offshore and onshore open trenching for pipe laying activities.
The west coast beaches are located within the Gulf of Paria which provides a sheltered environment. Erosion however was observed at North Chatham which averaged 1.20 m/yr since 2004. Erosion was also observed at the western section of Guapo Beach in Clifton Hill during 2006 and 2007. On the south-western peninsula, while Punta del Arenal (Icacos) is experiencing accretion, Columbus Bay is being eroded. The erosion has prompted property owners to employ the use of coastal protection measures such as revetments and groins. This report makes recommendations for modifying the current monitoring regime as well as highlights further research needs.
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Grande Riviere Beach, situated on the north coast of Trinidad, is an important nesting site for t... more Grande Riviere Beach, situated on the north coast of Trinidad, is an important nesting site for the leatherback turtle Dermochelys coriacea. During 2012, the eastern region of this beach experienced a high degree of erosion; the root cause was the hydrographic regime acting upon this area. Over a relatively short period, a great deal of sand loss was witnessed through continuous channelization and undercutting of the beachfront, culminating in the eventual threat to coastal structures. Remediative measures towards preservation of these structures were implemented via sand relocation and dam construction. Initial data analysis of the topographical changes to the beach highlight issues related to the hydrodynamics, and sustainability of built structures and ecological assets of this bay. By employing Real Time Kinematic Surveying techniques, during the present study, it was calculated that a total of 2036 m3 of sand was moved for dam construction. The short and long term impacts of this action on the bay and the adjoining infrastructure have not been assessed. This confirms the need for a thorough assessment of the various natural physical and hydrological processes that act upon the beach.
An Examination of the Morphological and Sedimentological Seasonal Changes at Cocos Bay
Analyzing Diurnal Changes in Beach Profiles and Sediment at Cocos Bay
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Conference Presentations by Junior Darsan Ph.D.
In this paper, cusp evolution is investigated to determine the factors which influence them within Maracas Bay, Trinidad, in the micro-tidal environment of the southern Caribbean. Data on beach profiles, beach
sediment, coastal processes, and cusp dimensions were collected using standard geomorphological techniques across daily, weekly and seasonal time-scales. Results indicate that beach cusp dimensions are
predominantly determined by beach volume and beach angle. These two parameters in turn are influenced by wave energy. In both the wet and dry seasons, periods of lower wave energy promote accretion, leading to the formation of smaller beach cusps; conversely, periods of higher wave energy and the associated increase in erosion result in the formation of larger beach cusps. There was agreement with the selforganization
theory since cusps were always present along the beach, constantly changing morphologically but never completely being erased and recreated anew. Beach cusps form an integral part of the total sediment deposited and retained on beaches over tidal and seasonal cycles, with implications for nearshore currents and beach safety. As such, a proper understanding of their dynamics will help support
planning and management of beaches as they go through cyclic phases annually.
The beaches on the north coast are less prone to erosion due to the more resilient metamorphic rocks that form these bays. However, changes in sand elevations due to normal wave processes do occur. During the period 2004–2008 all beaches monitored on the north coast experienced a state of dynamic equilibrium with the exception of the east and west stations at Las Cuevas Bays and the western part of Blanchisseuse Bay.
All east coast beaches also experienced dynamic equilibrium except the southern part of Cocos Bay. Erosion in this part of the coastline threatened to breach the roadway and prompted government to construct a 2 km long rip rap revetment as a means of shoreline protection. This has curbed the erosion in the protected area but to the extreme south erosion is ongoing at a rate of 2.5 m/yr since 2005.
The beaches on the south coast experienced dynamic equilibrium except at the western section of Guayaguayare Bay. Erosion in this part of the bay averaged 1.20 m/yr since 2004. This erosion can be attributed to both offshore and onshore open trenching for pipe laying activities.
The west coast beaches are located within the Gulf of Paria which provides a sheltered environment. Erosion however was observed at North Chatham which averaged 1.20 m/yr since 2004. Erosion was also observed at the western section of Guapo Beach in Clifton Hill during 2006 and 2007. On the south-western peninsula, while Punta del Arenal (Icacos) is experiencing accretion, Columbus Bay is being eroded. The erosion has prompted property owners to employ the use of coastal protection measures such as revetments and groins. This report makes recommendations for modifying the current monitoring regime as well as highlights further research needs.
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