Evaluación de los recursos acuíferos de Pativilca: desafíos y perspectivas

Abstract

The general objective of this research was to evaluate the sustainability of water resources in the Pativilca basin, which is related to: the lithological characteristics of the study area, the catchment area, and the latter in relation to the climatic factor. To this end, a methodology was developed based on the inventory of water sources, piezometric and hydrogeochemical monitoring, and a comparative historical analysis of the period 2015– 2024. The 2024 inventory identified 157 wells, almost evenly distributed between Barranca (49.68%) and Pativilca (50.32%). Of these, 24 wells are currently in operation, 49 are potentially usable, and 84 are non-operational. Eleven wells and four infiltration galleries have formal water rights. Groundwater extraction in 2024 reached 1.64 MCM through wells (0.05 m³/s) and 5.86 MCM through infiltration galleries (0.19 m³/s), with more than 99% of well extraction allocated to domestic use. Hydrogeologically, the aquifer is unconfined and shallow, with predominant NE–SW flow direction and hydraulic gradients ranging from 0.90% to 2.16%. Water table depth varies between 1.00 and 28.00 m depending on the zone. Trend analysis (2015–2024) shows that 82.76% of wells present equilibrium or slight decline trends (−0.08 to −0.03 m/year), while 17.24% exhibit moderate to strong declines (up to −0.24 m/year). Regarding water quality, electrical conductivity ranges from 0.595 to 1.166 mmhos/cm in middle and lower zones, with an overall increasing trend (up to 0.0727 mmhos/cm/year), particularly in coastal sectors. pH values range from 7.00 to 7.91, indicating slightly alkaline waters. Overall, the aquifer shows relative stability, though localized overexploitation and salinity increase highlight the need for sustainable management strategies.