Scale Dependency of Hydraulic Conductivity Measurements

Abstract

The hydraulic conductivity of five stratigraphic units in a carbonate aquifer has been measured with slug, pressure, and pumping tests, and with two calibrated digital models. The effective test radii range from less than one to greater than 10,000 meters. On log‐log plots hydraulic conductivity increases approximately linearly with test radius to a range between 20 and 220 meters, but thereafter, it is constant with scale. The increase in magnitude of hydraulic conductivity is similar to scaling effects reported at seven additional sites in a variety of geologic media. Moreover, the increase in magnitude correlates with an increase in variance of log‐hydraulic conductivity measured at successively greater separation distances. The rate of increase in both parameters, and particularly the range, have characteristic values for different pore systems. The larger ranges are consistently present in units with greater secondary porosity. Therefore, scaling effects provide a qualitative measure of the relative importance of secondary and primary permeability, and they can potentially be used to distinguish the dominant type of pore system.

Influence of groundwater on distribution of dwarf wedgemussels (<i>Alasmidonta heterodon</i>) in the upper reaches of the Delaware River, northeastern USA

“…For the entire site 2 reach, groundwater discharge would be about 10 to 20 m 3 d −1 . This is likely an underestimate as slug tests generally yield smaller values of K than more scale-appropriate methods (e.g., Schulze-Makuch et al, 1999;Rovey II and Cherkauer, 1995).…”

Measuring methods for groundwater – surface water interactions: a review

“…As Rovey and Cherkauer (1995) point out, hydraulic conductivity generally increases with test radius, because with a larger test radius the chance to encounter high-conductivity zones in a heterogeneous medium increases. Schulze-Makuch and Cherkauer (1998) found that hydraulic conductivity estimates increased during individual aquifer tests as the volume of aquifer impacted increased.…”

Numerical Simulation of Groundwater Flow in the Chateauguay River Aquifers

“…These are very close to the initial values and the geometric mean values discussed earlier, suggesting that the field data are representative of the regional hydraulic properties. Such coherent behaviour of the hydraulic conductivity at local and regional scales contrasts with other groundwater modelling studies where an up-scaling of the hydraulic properties was needed in order to calibrate the regional flow models (Rovey and Cherkauer, 1995;Sánchez-Vila et al, 1996;Schultze-Makuch and Cherkauer, 1998;Schultze-Makuch et al, 1999;Martinez-Landa and Carrera, 2005). However, to reproduce the observed high hydraulic gradients combined with relatively shallow hydraulic heads and relatively high horizontal hydraulic conductivities, the calibrated vertical anisotropy was increased significantly to more than four orders of magnitude in Covey Hill sandstone.…”