Determination of recharge rates using temperature‐depth profiles in wells

Abstract

Recharge rates to the shallow dolomite aquifer in northeastern Illinois are determined using a theory which describes the simultaneous transfer of heat and fluid in a porous medium. Temperature‐depth profiles in a nonpumping well are used to determine vertical groundwater velocities of the downward leakage of water recharging the aquifer which is overlain by semiconfining beds of clay‐rich glacial drift. Calculated and observed depths of penetration (19 m) of the annual surface temperature wave, and demonstration of the thermal stability of the well, validate application of the theory, which uses a dimensionless parameter β to relate curvature in temperature‐depth profiles to the magnitude of vertical leakage. Generally, the magnitude of β decreases as the depth interval L within the aquitard increases. The corresponding decrease in the vertical component of groundwater velocity accompanies a gradual coarsening with depth of the aquitard materials. Temperature differences over time at a given depth within a thermally stable well are found to be within the accuracy of the temperature measuring system. Analysis of variations in β Over time shows that the variability can be due to the limitations of the resolution (0.01°C) of the temperature measuring system. Recharge rates determined by analyses of temperature‐depth profiles range from 2.47×10−9 to 9.86×10−9 m/s and agree with estimates resulting from water‐budget method.

Groundwater–surface water interactions, vegetation dependencies and implications for water resources management in the semi-arid Hailiutu River catchment, China – a synthesis

“…The sum of squared difference between the left and right sides of the Eq. (3) can be minimized to find the optimal value of β as used by Boyle and Saleem (1979):…”

Alteration of the groundwater thermal regime caused by advection

“…Boyle & Saleem, 1979). Krige (1939) developed an expression for the critical gradient G of a fluid-filled column: c ga8 Cva where g = acceleration due to gravity; 0 = absolute temperature; a = volume coefficient of thermal expansion of the fluid; c = specific heat of the fluid; a = thermal diffusivity of the fluid; V = kinematic viscosity of the fluid; r = radius of the column; C = a constant, equal to 216 in cgs units.…”

Heat transport analysis and three‐dimensional thermo‐hydraulic simulation in the Ishikari basin, Hokkaido, Japan

“…Where there is significant flow through confining beds the resulting distortion in the temperature regime may be employed for computing velocity, and coupling the computed velocity with a known head distribution permits the estimation of hydraulic conductivity (Brown et al, 1972). Likewise, groundwater recharge or discharge rates can be calculated by using temperature-depth profiles of undisturbed wells (Cartwright, 1970;Boyle and Saleem, 1979). v z values (Table II) are computed along semi-confined layers of the deepest wells of the study field using:…”