TTE145

Vulnerabilidad de acuíferos de la subcuenca del Río Maullín…

ABSTRACT The water is a resource of vital importance for the sustainability and development of every nation. The demand this resource has grown, and will continue to do so largely due to constant population growth, either for the use of basics needs, as well as in the productive field both at the regional level and at the country level. In recent years, a sustained decrease in these reseource has been observed, of up to 20% in the southern macrozone. The latter has reached such a point that on April 5, 2021, the MOP declared the Province of Llanquihue an area of water scarcity. It can be said that there is currently poor knowledge of the degree of interconnections of aquifers, their vertical and horizontal extension and their level of recharge. In this context, the need to better understand the characteristics of the in the Maullín river Sub-basin has motivated the present work, with the elaboration of recommendations to carry out the protection of the river and its ecosystems. Through the use of information about the type of aquifer, piezometric levels, lithology, water wells, location and extension of urban wetlands in the Puerto Montt area, complemented with the main agents that generate hydraulic load towards the aquifers in which they are found inserts, the most vulnerable areas to contamination of the Sub-basin of the Maullín River were determined using the GOD method, together with the risk of contamination of the underground aquifers in the urban area of Puerto Montt using the POSH method. In this way, the existence of highly vunerable areas for the upper aquifer of the sub-basin was determinated, in addition to the presence of wetlands located in these areas, wich increases the sensitivity of the hydrogeological system to contaminating agents. The main reasons that explain the high degree of vulnerability in some areas correspond to the shallow level of groundwater and the type of surface lothology. Due to the similarity of lithologies in the study area and the widespread presence of a free aquifer, the depth of groundwater becomes the most differentiating element to obtain the different degrees of vulnerability. In addition, three levels of risk contamination of aquifers in the urban area of Puerto Montt were obtained, from the sources of contamination analyzed in this work.

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