Lessons to Be Learned: Groundwater Depletion in Chile’s Ligua and Petorca Watersheds through an Interdisciplinary Approach

Abstract

Groundwater (GW) is the primary source of unfrozen freshwater on the planet and in many semi-arid areas, it is the only source of water available during low-water periods. In north-central Chile, there has been GW depletion as a result of semi-arid conditions and high water demand, which has unleashed major social conflicts, some due to drought and others due to agribusiness practices against the backdrop of a private water management model. The Ligua and Petorca watersheds in the Valparaíso Region were studied in order to analyze the influence of climatic and anthropogenic factors on aquifer depletion using an interdisciplinary approach that integrates hydroclimatic variables, remote sensing data techniques, and GW rights data to promote sustainable GW management. The Standardized Precipitation Index (SPI) and Normalized Difference Vegetation Index (NDVI) were calculated and the 2002–2017 land-use change was analyzed. It was shown that GW decreased significantly (in 75% of the wells) and that the hydrological drought was moderate and prolonged (longest drought in the last 36 years). The avocado-growing area in Ligua increased significantly—by 2623 ha—with respect to other agricultural areas (higher GW decrease), while in Petorca, it decreased by 128 ha. In addition, GW-rainfall correlations were low and GW rights were granted continuously despite the drought. The results confirmed that aquifer depletion was mostly influenced by human factors due to overexploitation by agriculture and a lack of water management.

Establishment of Monterrey Pine (Pinus radiata) Plantations and Their Effects on Seasonal Sediment Yield in Central Chile

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Rapid groundwater decline and some cases of recovery in aquifers globally

“… 16 , 1312 ; Supplementary Note 14 ). We reviewed published and grey literature 20 , 427 , 802 , 1282 , 1313 – 1356 to obtain groundwater-level trends for some of the countries in which we lack monitoring-well data (that is, point data in Fig. 2 ; details available in Supplementary Note 15 ).…”

Taking advantage of water scarcity? Concentration of agricultural land and the politics behind water governance in Chile

“…Secondly, the separation between surface water rights and groundwater rights is fundamental when dealing with the phenomenon of scarcity, as it does not consider the water cycle as an integrated phenomenon involving surface flows and the recharge of aquifers and water bodies in general. The difference between these two types of rights in times of crisis has led to the overexploitation of river basins (Duran-Llacer et al, 2020).…”