USING SEEPAGE METERS AND MINI-PIEZOMETERS TO TEACH HYDROGEOLOGY

I have been using seepage meters (SM) and mini-piezometers (MP) in my part of a graduate course in field hydrology at the University of Waterloo since 1977. I also use this approach to teach the basics to environmental technicians at Algonquin College. While I have not compiled a list, this approach is also used at other schools.

After an introductory lecture, the students make their own MP screens. When we get to the field site, I do demonstrate installing and using these instruments. The students install their own SMs and MPs (one each) and make at least three consecutive measurements of gradient, seepage flux and MP flow. As the seepage bags increases in volume, they see the discharge of groundwater. Students use their data to examine the Darcy equation in detail. They relate seepage flux to measurements of hydraulic gradient and SM area. They calculate and compare values of K_Vertical and K_Horizontal. They calculate solute flux using their seepage fluxes and estimates of TDS (which is based on a relation of EC to TDS) and the EC of the MP discharge. The students interpret their individual and group data and draw various flow nets, so I can evaluate their understanding. Despite sometimes unpleasant weather and non-ideal conditions the students remain engaged and give the exercise a high rating because they are collecting their own data and seeing the flow of groundwater.

It is very much a hands-on learning experience and is loaded with opportunities to confront practical problems such as correctly installing and using instruments, dealing with hydrogeological heterogeneity and conceptualizing a flow system. Having enough equipment so every able-bodied individual can do everything is essential. The equipment list is long but is inexpensive.

I try to use field sites that have groundwater discharges of > 0.005 m³/m²day, vertical gradients > 0.01, surface-water movements < 0.4 m/s, sandy sediments and water depths < 0.5 m. However much can also be learned at sites that are less than ideal.