Evidence for Ground‐Water Circulation in the Brine‐Filled Aquitard, Oak Ridge, Tennessee

Abstract

Various geologic, hydrologic, and geochemical methods were used to assess active ground‐water circulation in a brine‐filled, deep (> 50 m below land surface) aquitard underlying the Oak Ridge Reservation, Tennessee. In places, the brine which was presumed to be stagnant in the past, contains various contaminants. If ground‐water circulation is viable in the brine‐containing formations, then remediation or containment of the deep‐seated contaminants should be considered a high priority. Data used to determine this included (1) spatial and temporal pressures and hydraulic heads measured in the aquitard, (2) hydraulic parameters of the formations in question, (3) vertical temperature gradients, and (4) spatial and temporal chemical and isotopic composition of the saline ground water. Conclusions suggest that the saline water contained at depth is not isolated (in terms of recharge and discharge) from the overlying active and fresh‐water‐ (< 500 mg/1) bearing units. Consequently, influx of young water (and contamination) from land surface does occur. Potential discharge into the shallow aquifers was assumed where the hydraulic head of the saline water was higher than that in the shallow aquifers, accounting for temperature and salinity anomalies observed close to land surface. The confined water (and dissolved solutes) move along open conduits at relatively high velocity into adjacent, more permeable units.

Environmental Sciences Division Groundwater Program Office report for fiscal years 1995--1997

“…Because of the depths involved, the heterogeneous nature of the fractured rock system, a limited number of observation points, the nature of the brines and the general complexity of the system, the results to date are inconclusive. Detailed results of investigations that have been conducted on the deep groundwater flow system are summarized by Nativ, 1996, Nativ et al, 1997aand Nativ et al, 1997b Briefly, some of the salient findings are: The deep ground water system is confined to semi-confind, as indicated by observed barometric pressure responses. The slow recovery of water level in many deep boreholes (2-8 years) following their purging demonstrates restricted flow.…”

Avaliação hidrogeológica e hidrogeoquímica das águas subterrâneas de Cuba Centro-Oriental com ênfase nas águas minerais

“…(1996) Moura, F. A, (1996) Santos, A .C. (1996) Hendry, M.J. e Schwartz, F.W, (1988) Nativ, Halleran, Hunley (1997 Autor 2001Os valores das áreas permitem estimar o caracter local ou regional das pesquisas relaclonadas. Comparando os valores das densidades alcançadas nas pesquisas selecionadas em áreas maiores de 15000 km' , pode-se notar que o autor conseguiu aumentar a densidade para estes trabalhos de grandes áreas, regionais.…”