GROUNDWATER FLOW BECOMES VISIBLE WITH SEEPAGE METERS AND MINI-PIEZOMETERS

An outdoor exercise (Lee and Cherry, 1979) has been part of a graduate course on field methods in hydrogeology at the University of Waterloo since 1977. Each student installs and uses a seepage meter and a mini-piezometer to complete an individual assignment. They measure the volumetric flow of water across the 0.25 m² area covered by a seepage meter. After quantifying the seepage flux, they use a piezometer to measure the hydraulic gradient and calculate the hydraulic conductivity between the piezometer screen and the seepage meter. If the piezometer is free flowing, they collect data for determining the hydraulic conductivity at the screen and they collect a groundwater sample, which is then used to estimate the solute flux into the surface-water body at that location. This exercise is feasible where 1) the rate of seepage is fast enough that replicate measurements can be made in the time available and 2) there is a discernable head difference in the piezometer compared with the surface water. The equipment is inexpensive. The activity has been meaningful for both graduate and college students. They see, by the labor of their hands, the movement of groundwater; gain perspectives on the basic principles of hydrogeology; and meet the physical challenges of a field endeavor. We will present a sample of free-access teaching material, including video clips, intended to support outdoor experiential teaching and on-line learning at the secondary-school level and above.