Long Term Effects of Human Induced Shoreline Changes: Veracruz Metropolitan Zone an Example of Port and Tourism Development in the Tropics

Human development in coastal zones is closely related with coastline modification due to coastal defense structures (CDS) and landfills. To contribute to a better understanding of long-term effects of CDS over three sensitive coastal natural systems: coral reefs, river inlets and sandy beaches in tropical areas, we used the Veracruz Bay (Mexico) as a case study, since it has all of the above mentioned environments and its development has included the construction of all types of CDS (breakwaters, groynes and jetties). A model of evolution was developed based on digitized coastlines from mosaicked historical aerial photographs. Historical CDS construction, coastline overlapping analysis to assess erosionaccretion and a sediment transport modelling resulted in the identification of long-term changes in sedimentation rates of up to 5 cm3 yr-1, which affects shallow coral reefs within a Marine Protected Area causing sub-lethal stress. We also identified accretion areas within port facilities which increase port maintenance costs. Accelerated erosion associated to CDS located in natural erosion areas was identified on touristic sandy beaches and deviations of the desired effect of jetties constructed in the Jamapa River inlet. All information reported here coincide with studies around the world on the effects of CDS but helps to reconstruct a case study that could be useful to understand the magnitude of long term impacts on coastal sensitive systems.