DESIGN OF A SEEPAGE METER FOR MEASURING GROUNDWATER FLUXES IN THE NONLITTORAL ZONES OF LAKES - EVALUATION IN A BOREAL FOREST LAKE

A lakebed seepage meter for measuring groundwater seepage rates in the nonlittoral zones of lakes was designed and field tested. Ease of installation and operation, sampling integrity, and year-round stability in ice-bound lake environments were the main factors governing design. The design of the meter incorporates a lake-bottom seepage meter connected by a flexible conduit hose to a sampling station approximately 2 m below lake surface. The operation and design of the meter includes methods for minimizing and monitoring meter settlement, protecting meter components from trawling fishermen and nibbling fish (seepage bags), visually monitoring flux levels in seepage bags to determine optimum time for sampling, and easy detection by a small boat-mounted sonar unit. Results from a seepage meter survey in a small lake situated in complex glacial stratigraphy show that the system is effective in measuring very low flux rates and mapping complex inflow and outflow groundwater regimes in lake environments.