Overview
I will offer a perspective on the evolution of NSG as a driver of interdisciplinary science over the last two decades, documenting successes and failures in a quest to establish relationships between geophysical observations and hydrogeological and biogeochemical properties and processes. Focusing on electrical geophysical techniques, I will draw upon examples where the unique qualities of NSG datasets advanced understanding of fluid flow and transport and biogeochemical transformations occurring across multiple scales within the Critical Zone. I will also highlight how NSG exemplifies solution-based science, by touching on environmental, geotechnical and archaeological examples of integration of science into practice. I will reflect on the frustrating potential pitfalls of near surface geophysics, most notably that (1) geophysical observations only provide proxies of the subsurface properties and processes of interest, and (2) inversion of geophysical datasets to produce images of the subsurface requires skill (and honesty) that, if lacking, can result in gross misinterpretation of the subsurface. However, the outlook for NSG as an essential interdisciplinary field of the earth sciences is overwhelmingly positive, as I will highlight with new opportunities for research and professional development of a diverse geoscience workforce.