SURFACE WATER INTERACTIONS WITH SHALLOW GROUNDWATER IN A HYDROLOGIC ALLY WELL-BOUNDED VALLEY IN CENTRAL CHILE

摘要

Agricultural production of high value crops in Chile's Central Valley is highly dependent on surface water and ground water, where interactions between the two are likely, yet hydrologic processes in the valley have not been well documented. This research addressed two study questions: 1) What is the effect of irrigation canal seepage on groundwater recharge; and 2) What are the within-valley spatial patterns of river-aquifer interactions. This study took place from 2003 to 2007 in the Peumo Valley at 34° South. Water levels rose after the onset of the irrigation season associated with irrigation canal seepage. The spatial relationship between river stage and valley shallow aquifer changedfrom an effluent river at the head of the valley to an influent river at the bottom of the valley. Hydrologic limitations to agricultural production in similar areas can be superceded by a system-wide appreciation of the interactions between surface water and groundwater.