Groundwater Quality Implications of Bank-Storage in a Crystalline-Rock Setting

Abstract

Numerical simulation of interaction between a river and adjacent alluvium and saprolite groundwaters in the Piedmont physiographic province of western Georgia, U.S.A. suggests that bank storage in this crystalline-rock setting is mediated by elastic storativity rather than the more commonly assumed piston flow. Hydraulic head responds almost instantly to river stage increase despite relatively low hydraulic conductivity of surficial materials. Modeling suggests that aquifer hydraulic head variation is primarily a pressure response to stream stage change and that very little infiltration of river water into alluvium and saprolite occurs. Most unconfined aquifer bank storage models do not account for elastic effects and will therefore greatly underpredict the rate and magnitude of groundwater hydraulic head change and greatly overpredict surface water infiltration. Results suggest that groundwater adjacent to this and similar streams in crystalline-rock settings is not necessarily threatened by contamination from passing surface-water flood waves, even when a strong hydraulic connection between river and groundwater exists and even in cases where hydraulic gradient reverses and is temporarily directed from the river into its banks. Because this site is typical of many near-stream sites in the Piedmont and other crystalline-rock settings, these results may be widely applicable.

Groundwater-surface water interaction in Lake Nasser, Southern Egypt

“…Rising water levels in lakes in response to inflow can induce flow from the lakes to the adjacent aquifers, and when the lake water level subsides, flow direction might reverse. Hydraulic heads in river banks can vary significantly over short time intervals in response to storm events, reversing temporarily hydraulic gradients allowing exchange of solutes between surface water and groundwater (Hunt, 1990;Vekerdy and Meijerink, 1998;Mayer et al, 2002).…”

Numerical Simulation of Groundwater System Change in a Riverside Area due to the Construction of an Artificial Structure

“…관련분야의 연구로는 하성충적층 주변의 지하수와 하천 수의 연계 해석을 위한 수리지질학적 연구 (Rossi et al, 1994;Woessner et al, 1998;Woessner, 2000;Alley et al, 2002;Hamm et al, 2002;Mayer et al, 2002;Cheong et al, 2003;Ha et al, 2006;Kim et al, 2006b;Cheong et al, 2008;Jeong and Kim, 2008;Kim et al, 2008), 지하수 수치모델링 (Anderson, 2003;Hamm et al, 2004;Won et al, 2006;Kim, 2008; Kim and Jeong, 2009;Lee et al, 2010;Chung et al, 2011), 수질 오염 특성 (Oh et al, 2002;Kang et al, 2006;Jeong and Moon, 2009;Park et al, 2009;Hwang et al, 2010;Choe et al, 2011), 지구화학적 특성 연구 (Linderfelt and Turner, 2001;Oxtobee and Novakowski, 2002;Kim et al, 2003;Negrel et al, 2003;Hyun et al, 2006;Choi et al, 2007;Bower et al, 2009;Kim and Nam, 2009;Lee et al, 2009a;Burt et al, 2011) 등이 수행되었다. 아 울러서 지하수와 하천수의 상호 작용은 하천 주변 대수 층의 다양한 수리지질학적 경계 조건들에 의해서도 좌 우된다 (Anderson, 2005).…”