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Groundwater recharge assessment in a rural, arid, mid-mountain basin in North-Central Chile

Sandoval, Eric, Baldo, Giacomo, Núñez, Jorge, Oyarzún, Jorge, Fairley, Jerry P., Ajami, Hoori, Arumí, José Luis, Aguirre, Evelyn, Maturana, Hugo, Oyarzún, Ricardo
Hydrological sciences journal 2018 v.63 no.13-14 pp. 1873-1889
atmospheric precipitation, basins, groundwater recharge, population density, temporal variation, Chile
A basic component of any hydrogeological study is the magnitude and temporal variation of groundwater recharge. This can be difficult to assess accurately, particularly in arid and semi-arid rainfed mid-mountain zones, as is the situation in the rural, low population density zones of North-Central Chile. In this study, recharge in the Punitaqui Basin, North-Central Chile, was characterized, contrasting the results of two methods: a modified Thornthwaite-Mather (MTM) and discharge recession analysis (DRA). We found a recharge rate of between 1 and 4% of average annual precipitation. Average recharge estimated by the MTM method is consistently higher than that estimated by DRA. Also, DRA tends to smooth the recharge values, resulting in a lower inter-annual variation coefficient. Both methods identified a threshold value of total annual precipitation, above which recharge can be expected to occur, of the order of 180 mm year⁻¹, consistent with values reported in similar areas.