Steady‐State Surface NMR for Mapping of Groundwater

Abstract

AbstractGroundwater is a critical freshwater source for billions of people (Klee, 2013), but resources are increasingly stressed by climate change, pollution, and overexploitation (Frappart & Ramillien, 2018, https://doi.org/10.3390/rs10060829). Locating groundwater sources and monitoring their sustainable use is a difficult task. One method that shows great promise is surface nuclear magnetic resonance (NMR), as it is the only technique capable of non‐invasive direct measurements of subsurface water content and pore‐space properties. Unfortunately, surface NMR often suffers from low‐amplitude signals that limit mapping speeds and may prohibit measurements in noisy environments. We demonstrate a steady‐state scheme for surface NMR, enabled by recent breakthroughs in transmitter capabilities and numerical modeling that delivers orders of magnitude signal enhancements. The new technique is a highly efficient measurement that is both narrowband and utilizes the full measurement interval in contrast to traditional approaches. Our results demonstrate that high‐fidelity groundwater measurements are now possible in hitherto inaccessible areas.