Riesgo geomorfológico de médanos migrantes: Minimización mediante la extracción de áridos en Arenas Verdes, municipio de Lobería (Buenos Aires)

Abstract

La localidad de Arenas Verdes es actualmente el único asentamiento turístico costero desarrollado en el partido de Lobería (Buenos Aires, Argentina). Se ubica sobre la Barrera Medanosa Austral, una de las cuatro que posee la provincia de Buenos Aires. Desde hace unas décadas, médanos barjanoides avanzan en dirección a la urbanización obliterando lotes y calles. El objetivo del trabajo fue aportar al municipio un instrumento de gestión que le posibilitará desarrollar procedimientos de recuperación de los terrenos soterrados por los médanos migrantes, mediante una política minera compatible con una gestión activa y ambientalmente sostenible, y con una mínima afectación de los ecosistemas costeros y de playa. Para lograr esto, se realizaron estudios cartográficos y con drone que determinaron la cantidad de predios afectados, así como la velocidad de avance de los frentes de médano. También se calculó la tasa de transporte eólico y se cubicó las arenas extraíbles, estimado la tasa máxima de extracción en función de ese transporte. Finalmente, se propusieron estrategias de manejo que eviten el avance de los médanos sobre la urbanización, orientando la actividad de la industria minera y a su vez, minimizar los efectos adversos antrópicos sobre el ecosistema medanoso.

The town of Arenas Verdes is currently the only coastal tourist settlement developed in the Lobería district (Buenos Aires, Argentina). It is located on the Barrera Medanosa Austral, one of the four in the province of Buenos Aires. For a few decades, barjanoid dunes have been advancing towards the urbanization, obliterating lots and streets. The objective of the work was to provide the municipality with a management tool that will enable it to develop procedures for the recovery of the land buried by migrant dunes, through a mining policy compatible with active and environmentally sustainable management, and with minimal impact on coastal ecosystems and beach. To achieve this, cartographic and drone studies were carried out that determined the number of affected properties, as well as the speed of advance of the dune fronts. The wind transport rate was also calculated and the extractable sands were cubed, estimating the maximum extraction rate based on this transport. Finally, management strategies were proposed to prevent the advance of the dunes over urbanization, orienting the activity of the mining industry and, in turn, minimizing adverse anthropic effects on dune ecosystem. It is concluded that in this area there are active prograding dunes that compromise the urban constructions established in the locality. To avoid this impact, it was proposed that only the leeward faces be exploited, always under strict sustainability criteria. In this way, the useful life of the deposit will be prolonged depending on the capture of the material that is in transit, as long as the mining activity extracts the same amount of sand that enters the system. Due to the long tradition of this activity in the Lobería district, ensuring the availability of sand is very important to supply urban development and local and regional infrastructure. Proper management translates into a rational and sustainable use of them, minimizing the risk of loss of environments due to anthropic activity.