Durable Development of Oasis Beach

Abstract

Storm safety and durability of touristic destinations is of utmost importance in Cuba, considering high stakes regarding life and capital invested in the development of the touristic sector. This twomonth research focuses on one of the largest Caribbean beach tourism hotspots found in Varadero, Cuba.

Tourism along the Hicacos peninsula has been on the rise and will continue to do so. The Oasis beach hotel is capitalizing on this trend by building a larger new hotel. However, no characteristic flat white coral beach is present in front of it. Tourist demand is greatly driven by the presence of such a beach. Year-round erosion was verified to be partly caused by a blocking of longshore sediment transport.

The local harbour groyne at the eastern beach section was found to be responsible for this but may not be adapted, as it is a necessity for the harbour entrance. Demolition of existing hydraulic structures, construction of a groyne at the westward boundary and sand nourishing are proposed as a zero-solution to ensure sufficient beach width (40 metres) at the 800-metre coastal segment.
Durability is not achieved through this zero-solution as the average lifetime between maintenance nourishments is smaller than one year.

This result shows that successful development of the Oasis beach sector can only be achieved by considering cross-shore erosion processes as well. An important aspect of the cross-shore transport was expected to be the effect of tropical storms on Oasis beach. To ensure the safety of tourists in storm conditions, an assessment of the infrastructure was required.

A multidisciplinary path was chosen to ensure safety of inhabitants, tourists and capital, especially during hurricanes. Flood safety, coastal engineering, transport and infrastructure form the core pillars of the research. Two distinct events were simulated to determine the morphodynamical response of the Oasis beach, namely hurricanes Wilma (2005) and Irma (2017). Both affected the northern coast of Cuba greatly, but passed Varadero from opposite directions. A general hurricane scenario was tested in evacuation assessments of the entire peninsula, which has just one exit road. Furthermore, the capacity of the current evacuation scheme was projected on the expected population and tourists visiting the peninsula in 2048.

Proposed coastal solutions were the construction of a submerged breakwater along the entire length of the beach, an artificial reef or a combination of the two. Normal, cold front and hurricane conditions were imposed upon these structures using XBeach software to test their performance. The subsequent infrastructural safety of the hinterlands was modelled using Simio software.

Results yielded good performance of the artificial reef against structural erosion from both the normal north-eastern wave climate and the northern cold front waves. The submerged breakwater performed better in hurricane conditions though extension of both groynes was found necessary to keep sediments within the Oasis beach system.

A multi criteria analysis was used to determine the best coastal intervention given the project requirements. Initially, no financial motives were used to determine the optimal solution. The results of this analysis stated a preference for the installation of an artificial reef. Its added recreational value was not quantified and thus not discounted from the initial investment. In detailed design, cost estimations of all viable design alternatives showed that the rtificial reef was also a relatively affordable option.

The final recommended design that ensures beach durability thus consists of: demolition of weathered hydraulic structures, western groyne placement, initial nourishment, artificial reef deployment and maintenance nourishment for a 30-year lifetime. A modelling of the definitive design with, also including the vegetation of the dunes indicated the Oasis beach section to be flood safe.

The total cost of this intervention amounts to approximately $900,000 and takes 28 months to complete. If monitored well, the artificial reef will increase its coastal defence capacities and functionality is expected to exceed the 30-year lifetime.

Recommendations regarding storm safety also include the evacuation process of tourists during the extreme hurricane conditions, on which the coastal design was based. Various projections of the growth of the number of tourists on the Hicacos peninsula have been simulated in a Simio evacuation transport model. The model indicated that even for the largest projected growth of tourism in Varadero, the infrastructure suffices and using a 50:50 ratio between evacuees being transported in buses and cars, it is possible to evacuate the peninsula in twenty-four hours.

To be able to evacuate using this optimal ratio, an increase in car ownership in Cuba is required before 2048, as a shortage exists in the current situation. Therefore, the peninsula is still considered storm-safe, but monitoring of the actual increase in tourists is advised.