Low-noise instrumentation for electromagnetic groundwater flow measurement

The flow of groundwater is complex. The traditional measurement method uses monitored wells, a process which is both difficult and expensive. This limits the ability to accurately tune models of the flow. An electromagnetic measurement technique has been proposed to simplify the measurement of groundwater flow and allow improved model tuning. The slow flow velocity of groundwater results in the need to measure small signals in a noisy environment. Additionally, AC measurements require highly synchronised timing between channels. This paper details the design and testing of instrumentation to measure these signals.