Field determination of stream-aquifer interrelations caused by intensive groundwater pumping for water right purposes

摘要

A hydrological simulation model has been developed to determine water balances along the agricultural valley of the Lluta River in which a system of groundwater wells is intensively pumped to supply fresh water to the city of Arica, located in the desert zone of Chile. The model consists of a water-balance surface water simulation, together with groundwater simulation. For purposes of calibration, a pumping test was run for 116 days and flows in canals and the river measured daily. The results showed reasonable adjustments between measured and simulated groundwater levels and surface flows. Prediction for a period of 50 years, determined that pumping rates of 370 1 s~(-1) from wells are sustainable by that system, in which 8% comes directly from the river. Based on this study, the National Water Agency decided to legally constitute that amount of groundwater to supply the city of Arica.