W. D. McFarland J.M. Wilkinson L. D. White K. A. McCarthy 1992 <p><span>Deuterium and oxygen-18 were used as natural tracers to investigate the hydraulic relationship between the Columbia River and the Blue Lake gravel aquifer near Portland, Oregon. A time series of stable-isotope data collected from surface and ground waters during a March 1990 aquifer test confirms that the river and aquifer are hydraulically connected. Calculations based on simple mixing show that the river contributed 40–50% of the yield of three wells after 5–6 days of pumping. Data collected during August 1990, show that the river contributed 65–80% of the yield of one well after 22 days of pumping and indicate that the contribution of the river was still increasing.</span></p> application/pdf 10.1016/0022-1694(92)90078-A en Elsevier The dynamic relationship between ground water and the Columbia River: Using deuterium and oxygen-18 as tracers article