Groundwater surveillance: a story of tiny sensors and their sizeable challenges

This study evaluates the performance of Micro Electro-Mechanical System (MEMS)-based sensors for groundwater/porewater pressure monitoring, focusing on their accuracy, calibration challenges, environmental sensitivity and long-term stability in terms of measuring porewater pressure and groundwater level. Laboratory and field experiments were conducted to assess the impact of sealant materials, temperature variations, barometric pressure corrections and noise filtering techniques on sensor performance. Results indicate that MEMS sensors offer a low-cost, scalable alternative to traditional vibrating wire piezometers, with comparable long-term precision after an initial stabilisation period. However, key limitations include complex calibration requirements, time lag in pressure dissipation when embedded in grout, and susceptibility to environmental anomalies such as temperature fluctuations and humidity changes. Despite some remaining technical challenges, MEMS-based groundwater sensors demonstrate strong potential for high-resolution, autonomous groundwater monitoring. Future research should focus on automating calibration processes, enhancing durability and refining environmental correction models to further improve MEMS for hydrological and geotechnical applications.