Evaluating the hydraulic conductivity at three different scales within an unconfined sand aquifer at Lachenaie, Quebec

This paper presents the evaluation of scale effects for the hydraulic conductivity, k, of a sand. Data were obtained using several methods at a site that was densely instrumented with piezometers within an area of about 100 m × 100 m. The 3.1–3.6 m thick sand deposit rests on a thick, nonfissured Champlain Sea clay deposit. At the small scale, local k values were obtained from the grain-size curves of sand samples and also from ground-penetrating radar surveys. At the intermediate scale, k values were obtained from field variable-head tests using piezometers. At the large scale, k values were obtained from pumping-test drawdowns in steady-state conditions. In this sand aquifer, the careful evaluations at three scales gave similar narrow distributions for the hydraulic conductivity, and therefore no scale effect is evidenced.