Erosion and coastal planning in Las Toninas, Partido de la costa, province of Buenos Aires

Many coastal communities experienced dramatic growth by the end of 1970s, with the construction of high-rise condominiums, buildings, roads and related features on the ocean front. The purpose of this paper is to supply a new methodology of analysis for environmental impact evaluation in coastal areas based on the most susceptible geological features to natural and anthropogenic changes. It consists on the development of an environmental matrix with the analysis of different parameters such as dune conservation, coastal and beach erosion, beach configuration, runoff and beach natural cycles. The analysis shows that the northern sector of the locality, between streets 4 and 10, has the highest vulnerability, the coastal area between 10 and 18 has a moderate vulnerability and the southern sector between 18th and 50th street present a low vulnerability to erosion. The highest values obtained for the northern coast were due to sand mining which stopped several years ago. The vertical erosion determined was 1.33 m on the foreshore and 1.2 m on the backshore. This vertical area on the beach profile should be considered as a security margin to design futures constructions on the beach. Considering the coastal management, in the coastal zones defined as of high vulnerability to erosion no protection or mitigation works have been effective, and the properties located on the ocean front shoulb be relocated. In the areas identified as of moderate or low vulnerability to erosion, are still feasible remediation tasks at low cost and good efficiency.