Groundwater flow meters that measure horizontal flow direction and velocity have been used by the USGS in a variety of investigations across the country. Traditionally, these instruments required on-site operation and supported investigative studies of contaminant plumes (such as TCE and PFAS) to aid in site characterization and remedial planning, as well as to evaluate aquifer test responses and production well influence. As part of the NGWOS Illinois Basin Study, groundwater flow meters have been deployed for long-term, telemetered monitoring at two testbed sites to help characterize groundwater flow and direction to assess groundwater–surface water interactions between streams and nearby agricultural areas. Recently, as part of the NGWOS Research and Development sub-program, work has commenced to develop a heat pulse flowmeter that is capable of measuring flow direction and velocity in 3-dimensional space rather than being limited to the horizontal plane. This presentation will provide an overview of available technologies, guidance on proper deployment and operation, case studies, best management practices, and research and development of a new multi-dimensional instrument.
