Rodolfo Silva-Casarín

MONITORING SHORELINE CHANGES AT CANCUN BEACH, MEXICO: EFFECTS OF HURRICANE WILMA

Cancun beach is one of Mexicos most important coastal resorts and is of paramount importance for the local and national economies. Following the tendency of the time (1970s and 80s), this very large strip-development was built along 17km of coastal dunes on a barrier island on the Mexican Caribbean coast. A very large development, the concentration of buildings in a limited space and the unavailability of sand reserves, has meant that the extreme weather events that occur in the region (hurricanes) have permanently damaged the beach. The effects of hurricane Gilbert in 1988 were especially harmful, Ivan in 2004 and Emily in July 2005 weakened the system, but Wilma (October 2005) caused extreme damage to the beach and coastal infrastructure. As a consequence of the hurricanes prior to Wilma and chronic shoreline recession, the beach had been experiencing receding rates of 2 m/year since 1984. This paper describes the shoreline monitoring system implemented in Cancun in May 2005 which aims to better understand shoreline changes using field data, satellite images, video monitoring, and numerical modeling. The results focus on the effects hurricane Wilma had on the beach. Hurricanedriven erosion presented non-uniform changes along the beach with pronounced accretion in the southern section (15 m beach width gain), and intercalated zones of beach disappearance and eroded but existent beach (~15 m wide).

AN EXPERIMENTAL EVALUATION OF WAVE ENERGY DISSIPATION DUE TO SUBMERGED STRUCTURES

An experimental work regarding a group of submerged structures constructed of different materials is presented. The efficiency of each structure related to energy dissipation and the response of a beach profile is analyzed. Among the results, a strong dependency in porosity has been found. The deformation of the sheltered beach and the distribution of the sediment along the profile are used to rank the tested materials. and Javier L. Lara 3

The Influence of Climate Change on Coastal Erosion Vulnerability in Northeast Brazil

In this paper, an adapted methodology to evaluate coastal erosion vulnerability, which provides a basis for decision-making concerning risk management strategies, is described. The vulnerability evaluation was based on weighted indicators and assessed the vulnerability under different climate change scenarios. To generate the vulnerability index, dynamic processes, geo-indicators, and social and morphological parameters associated with modeled scenarios of sea level rise and predicted wave height changes were integrated. The study area included the sandy beaches in Pernambuco, NE Brazil, and was used to describe the practical application of this approach. Because the occupation of large sectors of the coastline was low, the vulnerability was concentrated in urbanized areas. The high-vulnerability sections of the coast were those with high population densities, high-rise buildings, induced coastal squeeze and hard engineering structures. The low-vulnerability beaches generally had low urbanization rates and well-conserved, resilient coastlines. Under future scenarios, the vulnerability of this coastal region will increase with sea level rise and wave height changes.